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diff --git a/doc/Pacemaker_Administration/en-US/Ch-Agents.txt b/doc/Pacemaker_Administration/en-US/Ch-Agents.txt
index ab82420f58..1cb2e252a3 100644
--- a/doc/Pacemaker_Administration/en-US/Ch-Agents.txt
+++ b/doc/Pacemaker_Administration/en-US/Ch-Agents.txt
@@ -1,337 +1,337 @@
= Resource Agents =
== OCF Resource Agents ==
=== Location of Custom Scripts ===
indexterm:[OCF Resource Agents]
OCF Resource Agents are found in +/usr/lib/ocf/resource.d/pass:[<replaceable>provider</replaceable>]+
When creating your own agents, you are encouraged to create a new
directory under +/usr/lib/ocf/resource.d/+ so that they are not
confused with (or overwritten by) the agents shipped by existing providers.
So, for example, if you choose the provider name of bigCorp and want
a new resource named bigApp, you would create a resource agent called
+/usr/lib/ocf/resource.d/bigCorp/bigApp+ and define a resource:
[source,XML]
----
<primitive id="custom-app" class="ocf" provider="bigCorp" type="bigApp"/>
----
=== Actions ===
All OCF resource agents are required to implement the following actions.
.Required Actions for OCF Agents
[width="95%",cols="3m,3,7",options="header",align="center"]
|=========================================================
|Action
|Description
|Instructions
|start
|Start the resource
|Return 0 on success and an appropriate error code otherwise. Must not
report success until the resource is fully active.
indexterm:[start,OCF Action]
indexterm:[OCF,Action,start]
|stop
|Stop the resource
|Return 0 on success and an appropriate error code otherwise. Must not
report success until the resource is fully stopped.
indexterm:[stop,OCF Action]
indexterm:[OCF,Action,stop]
|monitor
|Check the resource's state
|Exit 0 if the resource is running, 7 if it is stopped, and anything
else if it is failed.
indexterm:[monitor,OCF Action]
indexterm:[OCF,Action,monitor]
NOTE: The monitor script should test the state of the resource on the local machine only.
|meta-data
|Describe the resource
|Provide information about this resource as an XML snippet. Exit with 0.
indexterm:[meta-data,OCF Action]
indexterm:[OCF,Action,meta-data]
NOTE: This is _not_ performed as root.
|validate-all
|Verify the supplied parameters
|Return 0 if parameters are valid, 2 if not valid, and 6 if resource is not configured.
indexterm:[validate-all,OCF Action]
indexterm:[OCF,Action,validate-all]
|=========================================================
Additional requirements (not part of the OCF specification) are placed on
agents that will be used for advanced concepts such as clone resources.
.Optional Actions for OCF Resource Agents
[width="95%",cols="2m,6,3",options="header",align="center"]
|=========================================================
|Action
|Description
|Instructions
|promote
|Promote the local instance of a promotable clone resource to the master (primary) state.
|Return 0 on success
indexterm:[promote,OCF Action]
indexterm:[OCF,Action,promote]
|demote
|Demote the local instance of a promotable clone resource to the slave (secondary) state.
|Return 0 on success
indexterm:[demote,OCF Action]
indexterm:[OCF,Action,demote]
|notify
|Used by the cluster to send the agent pre- and post-notification
events telling the resource what has happened and will happen.
|Must not fail. Must exit with 0
indexterm:[notify,OCF Action]
indexterm:[OCF,Action,notify]
|=========================================================
One action specified in the OCF specs, +recover+, is not currently used by the
cluster. It is intended to be a variant of the +start+ action that tries to
recover a resource locally.
[IMPORTANT]
====
If you create a new OCF resource agent, use indexterm:[ocf-tester]`ocf-tester`
to verify that the agent complies with the OCF standard properly.
====
=== How are OCF Return Codes Interpreted? ===
The first thing the cluster does is to check the return code against
the expected result. If the result does not match the expected value,
then the operation is considered to have failed, and recovery action is
initiated.
There are three types of failure recovery:
.Types of recovery performed by the cluster
[width="95%",cols="1m,4,4",options="header",align="center"]
|=========================================================
|Type
|Description
|Action Taken by the Cluster
|soft
|A transient error occurred
|Restart the resource or move it to a new location
indexterm:[soft,OCF error]
indexterm:[OCF,error,soft]
|hard
|A non-transient error that may be specific to the current node occurred
|Move the resource elsewhere and prevent it from being retried on the current node
indexterm:[hard,OCF error]
indexterm:[OCF,error,hard]
|fatal
|A non-transient error that will be common to all cluster nodes (e.g. a bad configuration was specified)
|Stop the resource and prevent it from being started on any cluster node
indexterm:[fatal,OCF error]
indexterm:[OCF,error,fatal]
|=========================================================
[[s-ocf-return-codes]]
=== OCF Return Codes ===
The following table outlines the different OCF return codes and the type of
recovery the cluster will initiate when a failure code is received.
Although counterintuitive, even actions that return 0
(aka. +OCF_SUCCESS+) can be considered to have failed, if 0 was not
the expected return value.
.OCF Return Codes and their Recovery Types
-[width="95%",cols="1m,4<m,6<,1m",options="header",align="center"]
+[width="95%",cols="1m,<4m,<6,1m",options="header",align="center"]
|=========================================================
|RC
|OCF Alias
|Description
|RT
|0
|OCF_SUCCESS
|Success. The command completed successfully. This is the expected result for all start, stop, promote and demote commands.
indexterm:[Return Code,OCF_SUCCESS]
indexterm:[Return Code,0,OCF_SUCCESS]
|soft
|1
|OCF_ERR_GENERIC
|Generic "there was a problem" error code.
indexterm:[Return Code,OCF_ERR_GENERIC]
indexterm:[Return Code,1,OCF_ERR_GENERIC]
|soft
|2
|OCF_ERR_ARGS
|The resource's configuration is not valid on this machine. E.g. it refers to a location not found on the node.
indexterm:[Return Code,OCF_ERR_ARGS]
indexterm:[Return Code,2,OCF_ERR_ARGS]
|hard
|3
|OCF_ERR_UNIMPLEMENTED
|The requested action is not implemented.
indexterm:[Return Code,OCF_ERR_UNIMPLEMENTED]
indexterm:[Return Code,3,OCF_ERR_UNIMPLEMENTED]
|hard
|4
|OCF_ERR_PERM
|The resource agent does not have sufficient privileges to complete the task.
indexterm:[Return Code,OCF_ERR_PERM]
indexterm:[Return Code,4,OCF_ERR_PERM]
|hard
|5
|OCF_ERR_INSTALLED
|The tools required by the resource are not installed on this machine.
indexterm:[Return Code,OCF_ERR_INSTALLED]
indexterm:[Return Code,5,OCF_ERR_INSTALLED]
|hard
|6
|OCF_ERR_CONFIGURED
|The resource's configuration is invalid. E.g. required parameters are missing.
indexterm:[Return Code,OCF_ERR_CONFIGURED]
indexterm:[Return Code,6,OCF_ERR_CONFIGURED]
|fatal
|7
|OCF_NOT_RUNNING
|The resource is safely stopped. The cluster will not attempt to stop a resource that returns this for any action.
indexterm:[Return Code,OCF_NOT_RUNNING]
indexterm:[Return Code,7,OCF_NOT_RUNNING]
|N/A
|8
|OCF_RUNNING_MASTER
|The resource is running in master mode.
indexterm:[Return Code,OCF_RUNNING_MASTER]
indexterm:[Return Code,8,OCF_RUNNING_MASTER]
|soft
|9
|OCF_FAILED_MASTER
|The resource is in master mode but has failed. The resource will be demoted,
stopped and then started (and possibly promoted) again.
indexterm:[Return Code,OCF_FAILED_MASTER]
indexterm:[Return Code,9,OCF_FAILED_MASTER]
|soft
|other
|N/A
|Custom error code.
indexterm:[Return Code,other]
|soft
|=========================================================
Exceptions to the recovery handling described above:
* Probes (non-recurring monitor actions) that find a resource active
(or in master mode) will not result in recovery action unless it is
also found active elsewhere.
* The recovery action taken when a resource is found active more than
once is determined by the resource's +multiple-active+ property.
* Recurring actions that return +OCF_ERR_UNIMPLEMENTED+
do not cause any type of recovery.
== Init Script LSB Compliance ==
The relevant part of the
http://refspecs.linuxfoundation.org/lsb.shtml[LSB specifications]
includes a description of all the return codes listed here.
Assuming `some_service` is configured correctly and currently
inactive, the following sequence will help you determine if it is
LSB-compatible:
. Start (stopped):
+
----
# /etc/init.d/some_service start ; echo "result: $?"
----
+
.. Did the service start?
.. Did the command print *result: 0* (in addition to its usual output)?
+
. Status (running):
+
----
# /etc/init.d/some_service status ; echo "result: $?"
----
+
.. Did the script accept the command?
.. Did the script indicate the service was running?
.. Did the command print *result: 0* (in addition to its usual output)?
+
. Start (running):
+
----
# /etc/init.d/some_service start ; echo "result: $?"
----
+
.. Is the service still running?
.. Did the command print *result: 0* (in addition to its usual output)?
+
. Stop (running):
+
----
# /etc/init.d/some_service stop ; echo "result: $?"
----
+
.. Was the service stopped?
.. Did the command print *result: 0* (in addition to its usual output)?
+
. Status (stopped):
+
----
# /etc/init.d/some_service status ; echo "result: $?"
----
+
.. Did the script accept the command?
.. Did the script indicate the service was not running?
.. Did the command print *result: 3* (in addition to its usual output)?
+
. Stop (stopped):
+
----
# /etc/init.d/some_service stop ; echo "result: $?"
----
+
.. Is the service still stopped?
.. Did the command print *result: 0* (in addition to its usual output)?
+
. Status (failed):
+
.. This step is not readily testable and relies on manual inspection of the script.
+
The script can use one of the error codes (other than 3) listed in the
LSB spec to indicate that it is active but failed. This tells the
cluster that before moving the resource to another node, it needs to
stop it on the existing one first.
If the answer to any of the above questions is no, then the script is
not LSB-compliant. Your options are then to either fix the script or
write an OCF agent based on the existing script.
diff --git a/doc/Pacemaker_Administration/en-US/Ch-Configuring.txt b/doc/Pacemaker_Administration/en-US/Ch-Configuring.txt
index cffe780bbf..473e5b5299 100644
--- a/doc/Pacemaker_Administration/en-US/Ch-Configuring.txt
+++ b/doc/Pacemaker_Administration/en-US/Ch-Configuring.txt
@@ -1,435 +1,435 @@
= Configuring Pacemaker =
== How Should the Configuration be Updated? ==
There are three basic rules for updating the cluster configuration:
* Rule 1 - Never edit the +cib.xml+ file manually. Ever. I'm not making this up.
* Rule 2 - Read Rule 1 again.
* Rule 3 - The cluster will notice if you ignored rules 1 &amp; 2 and refuse to use the configuration.
Now that it is clear how 'not' to update the configuration, we can begin
to explain how you 'should'.
=== Editing the CIB Using XML ===
The most powerful tool for modifying the configuration is the
+cibadmin+ command. With +cibadmin+, you can query, add, remove, update
or replace any part of the configuration. All changes take effect immediately,
so there is no need to perform a reload-like operation.
The simplest way of using `cibadmin` is to use it to save the current
configuration to a temporary file, edit that file with your favorite
text or XML editor, and then upload the revised configuration. footnote:[This
process might appear to risk overwriting changes that happen after the initial
cibadmin call, but pacemaker will reject any update that is "too old". If the
CIB is updated in some other fashion after the initial cibadmin, the second
cibadmin will be rejected because the version number will be too low.]
.Safely using an editor to modify the cluster configuration
======
--------
# cibadmin --query > tmp.xml
# vi tmp.xml
# cibadmin --replace --xml-file tmp.xml
--------
======
Some of the better XML editors can make use of a Relax NG schema to
help make sure any changes you make are valid. The schema describing
the configuration can be found in +pacemaker.rng+, which may be
deployed in a location such as +/usr/share/pacemaker+ or
+/usr/lib/heartbeat+ depending on your operating system and how you
installed the software.
If you want to modify just one section of the configuration, you can
query and replace just that section to avoid modifying any others.
.Safely using an editor to modify only the resources section
======
--------
# cibadmin --query --scope resources > tmp.xml
# vi tmp.xml
# cibadmin --replace --scope resources --xml-file tmp.xml
--------
======
=== Quickly Deleting Part of the Configuration ===
Identify the object you wish to delete by XML tag and id. For example,
you might search the CIB for all STONITH-related configuration:
.Searching for STONITH-related configuration items
======
----
# cibadmin -Q | grep stonith
<nvpair id="cib-bootstrap-options-stonith-action" name="stonith-action" value="reboot"/>
<nvpair id="cib-bootstrap-options-stonith-enabled" name="stonith-enabled" value="1"/>
<primitive id="child_DoFencing" class="stonith" type="external/vmware">
<lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
<lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
<lrm_resource id="child_DoFencing:1" type="external/vmware" class="stonith">
<lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
<lrm_resource id="child_DoFencing:2" type="external/vmware" class="stonith">
<lrm_resource id="child_DoFencing:0" type="external/vmware" class="stonith">
<lrm_resource id="child_DoFencing:3" type="external/vmware" class="stonith">
----
======
If you wanted to delete the +primitive+ tag with id +child_DoFencing+,
you would run:
----
# cibadmin --delete --xml-text '<primitive id="child_DoFencing"/>'
----
=== Updating the Configuration Without Using XML ===
Most tasks can be performed with one of the other command-line
tools provided with pacemaker, avoiding the need to read or edit XML.
To enable STONITH for example, one could run:
----
# crm_attribute --name stonith-enabled --update 1
----
Or, to check whether *somenode* is allowed to run resources, there is:
----
# crm_standby --query --node somenode
----
Or, to find the current location of *my-test-rsc*, one can use:
----
# crm_resource --locate --resource my-test-rsc
----
Examples of using these tools for specific cases will be given throughout this
document where appropriate.
[[s-config-sandboxes]]
== Making Configuration Changes in a Sandbox ==
Often it is desirable to preview the effects of a series of changes
before updating the configuration all at once. For this purpose, we
have created `crm_shadow` which creates a
"shadow" copy of the configuration and arranges for all the command
line tools to use it.
To begin, simply invoke `crm_shadow --create` with
the name of a configuration to create footnote:[Shadow copies are
identified with a name, making it possible to have more than one.],
and follow the simple on-screen instructions.
[WARNING]
====
Read this section and the on-screen instructions carefully; failure to do so could
result in destroying the cluster's active configuration!
====
.Creating and displaying the active sandbox
======
----
# crm_shadow --create test
Setting up shadow instance
Type Ctrl-D to exit the crm_shadow shell
shadow[test]:
shadow[test] # crm_shadow --which
test
----
======
From this point on, all cluster commands will automatically use the
shadow copy instead of talking to the cluster's active configuration.
Once you have finished experimenting, you can either make the
changes active via the `--commit` option, or discard them using the `--delete`
option. Again, be sure to follow the on-screen instructions carefully!
For a full list of `crm_shadow` options and
commands, invoke it with the `--help` option.
.Use sandbox to make multiple changes all at once, discard them, and verify real configuration is untouched
======
----
shadow[test] # crm_failcount -r rsc_c001n01 -G
scope=status name=fail-count-rsc_c001n01 value=0
shadow[test] # crm_standby --node c001n02 -v on
shadow[test] # crm_standby --node c001n02 -G
scope=nodes name=standby value=on
shadow[test] # cibadmin --erase --force
shadow[test] # cibadmin --query
<cib crm_feature_set="3.0.14" validate-with="pacemaker-3.0" epoch="112" num_updates="2" admin_epoch="0" cib-last-written="Mon Jan 8 23:26:47 2018" update-origin="rhel7-1" update-client="crm_node" update-user="root" have-quorum="1" dc-uuid="1">
<configuration>
<crm_config/>
<nodes/>
<resources/>
<constraints/>
</configuration>
<status/>
</cib>
shadow[test] # crm_shadow --delete test --force
Now type Ctrl-D to exit the crm_shadow shell
shadow[test] # exit
# crm_shadow --which
No active shadow configuration defined
# cibadmin -Q
<cib crm_feature_set="3.0.14" validate-with="pacemaker-3.0" epoch="110" num_updates="2" admin_epoch="0" cib-last-written="Mon Jan 8 23:26:47 2018" update-origin="rhel7-1" update-client="crm_node" update-user="root" have-quorum="1">
<configuration>
<crm_config>
<cluster_property_set id="cib-bootstrap-options">
<nvpair id="cib-bootstrap-1" name="stonith-enabled" value="1"/>
<nvpair id="cib-bootstrap-2" name="pe-input-series-max" value="30000"/>
----
======
[[s-config-testing-changes]]
== Testing Your Configuration Changes ==
We saw previously how to make a series of changes to a "shadow" copy
of the configuration. Before loading the changes back into the
cluster (e.g. `crm_shadow --commit mytest --force`), it is often
advisable to simulate the effect of the changes with +crm_simulate+.
For example:
----
# crm_simulate --live-check -VVVVV --save-graph tmp.graph --save-dotfile tmp.dot
----
This tool uses the same library as the live cluster to show what it
would have done given the supplied input. Its output, in addition to
a significant amount of logging, is stored in two files +tmp.graph+
and +tmp.dot+. Both files are representations of the same thing: the
cluster's response to your changes.
The graph file stores the complete transition from the existing cluster state
to your desired new state, containing a list of all the actions, their
parameters and their pre-requisites. Because the transition graph is not
terribly easy to read, the tool also generates a Graphviz
footnote:[Graph visualization software. See http://www.graphviz.org/ for details.]
dot-file representing the same information.
For information on the options supported by `crm_simulate`, use
its `--help` option.
.Interpreting the Graphviz output
* Arrows indicate ordering dependencies
* Dashed arrows indicate dependencies that are not present in the transition graph
* Actions with a dashed border of any color do not form part of the transition graph
* Actions with a green border form part of the transition graph
* Actions with a red border are ones the cluster would like to execute but cannot run
* Actions with a blue border are ones the cluster does not feel need to be executed
* Actions with orange text are pseudo/pretend actions that the cluster uses to simplify the graph
* Actions with black text are sent to the LRM
* Resource actions have text of the form pass:[<replaceable>rsc</replaceable>]_pass:[<replaceable>action</replaceable>]_pass:[<replaceable>interval</replaceable>] pass:[<replaceable>node</replaceable>]
* Any action depending on an action with a red border will not be able to execute.
* Loops are _really_ bad. Please report them to the development team.
=== Small Cluster Transition ===
image::images/Policy-Engine-small.png["An example transition graph as represented by Graphviz",width="16cm",height="6cm",align="center"]
In the above example, it appears that a new node, *pcmk-2*, has come
online and that the cluster is checking to make sure *rsc1*, *rsc2*
and *rsc3* are not already running there (Indicated by the
*rscN_monitor_0* entries). Once it did that, and assuming the resources
were not active there, it would have liked to stop *rsc1* and *rsc2*
on *pcmk-1* and move them to *pcmk-2*. However, there appears to be
some problem and the cluster cannot or is not permitted to perform the
stop actions which implies it also cannot perform the start actions.
For some reason the cluster does not want to start *rsc3* anywhere.
=== Complex Cluster Transition ===
image::images/Policy-Engine-big.png["Another, slightly more complex, transition graph that you're not expected to be able to read",width="16cm",height="20cm",align="center"]
== Do I Need to Update the Configuration on All Cluster Nodes? ==
No. Any changes are immediately synchronized to the other active
members of the cluster.
To reduce bandwidth, the cluster only broadcasts the incremental
updates that result from your changes and uses MD5 checksums to ensure
that each copy is completely consistent.
== Working with CIB Properties ==
Although these fields can be written to by the user, in
most cases the cluster will overwrite any values specified by the
user with the "correct" ones.
To change the ones that can be specified by the user,
for example +admin_epoch+, one should use:
----
# cibadmin --modify --xml-text '<cib admin_epoch="42"/>'
----
A complete set of CIB properties will look something like this:
.Attributes set for a cib object
======
[source,XML]
-------
<cib crm_feature_set="3.0.7" validate-with="pacemaker-1.2"
admin_epoch="42" epoch="116" num_updates="1"
cib-last-written="Mon Jan 12 15:46:39 2015" update-origin="rhel7-1"
update-client="crm_attribute" have-quorum="1" dc-uuid="1">
-------
======
== Querying and Setting Cluster Options ==
indexterm:[Querying,Cluster Option]
indexterm:[Setting,Cluster Option]
indexterm:[Cluster,Querying Options]
indexterm:[Cluster,Setting Options]
Cluster options can be queried and modified using the `crm_attribute` tool. To
get the current value of +cluster-delay+, you can run:
----
# crm_attribute --query --name cluster-delay
----
which is more simply written as
----
# crm_attribute -G -n cluster-delay
----
If a value is found, you'll see a result like this:
----
# crm_attribute -G -n cluster-delay
scope=crm_config name=cluster-delay value=60s
----
If no value is found, the tool will display an error:
----
# crm_attribute -G -n clusta-deway
scope=crm_config name=clusta-deway value=(null)
Error performing operation: No such device or address
----
To use a different value (for example, 30 seconds), simply run:
----
# crm_attribute --name cluster-delay --update 30s
----
To go back to the cluster's default value, you can delete the value, for example:
----
# crm_attribute --name cluster-delay --delete
Deleted crm_config option: id=cib-bootstrap-options-cluster-delay name=cluster-delay
----
=== When Options are Listed More Than Once ===
If you ever see something like the following, it means that the option you're modifying is present more than once.
.Deleting an option that is listed twice
=======
------
# crm_attribute --name batch-limit --delete
Multiple attributes match name=batch-limit in crm_config:
Value: 50 (set=cib-bootstrap-options, id=cib-bootstrap-options-batch-limit)
Value: 100 (set=custom, id=custom-batch-limit)
Please choose from one of the matches above and supply the 'id' with --id
-------
=======
In such cases, follow the on-screen instructions to perform the
requested action. To determine which value is currently being used by
the cluster, refer to the 'Rules' chapter of 'Pacemaker Explained'.
[[s-remote-connection]]
== Connecting from a Remote Machine ==
indexterm:[Cluster,Remote connection]
indexterm:[Cluster,Remote administration]
Provided Pacemaker is installed on a machine, it is possible to
connect to the cluster even if the machine itself is not in the same
cluster. To do this, one simply sets up a number of environment
variables and runs the same commands as when working on a cluster
node.
.Environment Variables Used to Connect to Remote Instances of the CIB
-[width="95%",cols="1m,1,3<",options="header",align="center"]
+[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Environment Variable
|Default
|Description
|CIB_user
|$USER
|The user to connect as. Needs to be part of the +haclient+ group on
the target host.
indexterm:[Environment Variable,CIB_user]
|CIB_passwd
|
|The user's password. Read from the command line if unset.
indexterm:[Environment Variable,CIB_passwd]
|CIB_server
|localhost
|The host to contact
indexterm:[Environment Variable,CIB_server]
|CIB_port
|
|The port on which to contact the server; required.
indexterm:[Environment Variable,CIB_port]
|CIB_encrypted
|TRUE
|Whether to encrypt network traffic
indexterm:[Environment Variable,CIB_encrypted]
|=========================================================
So, if *c001n01* is an active cluster node and is listening on port 1234
for connections, and *someuser* is a member of the *haclient* group,
then the following would prompt for *someuser*'s password and return
the cluster's current configuration:
----
# export CIB_port=1234; export CIB_server=c001n01; export CIB_user=someuser;
# cibadmin -Q
----
For security reasons, the cluster does not listen for remote
connections by default. If you wish to allow remote access, you need
to set the +remote-tls-port+ (encrypted) or +remote-clear-port+
(unencrypted) CIB properties (i.e., those kept in the +cib+ tag, like
+num_updates+ and +epoch+).
.Extra top-level CIB properties for remote access
-[width="95%",cols="1m,1,3<",options="header",align="center"]
+[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|remote-tls-port
|_none_
|Listen for encrypted remote connections on this port.
indexterm:[remote-tls-port,Remote Connection Option]
indexterm:[Remote Connection,Option,remote-tls-port]
|remote-clear-port
|_none_
|Listen for plaintext remote connections on this port.
indexterm:[remote-clear-port,Remote Connection Option]
indexterm:[Remote Connection,Option,remote-clear-port]
|=========================================================
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
index fbd992267d..c662c60a49 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
@@ -1,728 +1,728 @@
= Advanced Configuration =
[[s-recurring-start]]
== Specifying When Recurring Actions are Performed ==
By default, recurring actions are scheduled relative to when the
resource started. So if your resource was last started at 14:32 and
you have a backup set to be performed every 24 hours, then the backup
will always run in the middle of the business day -- hardly
desirable.
To specify a date and time that the operation should be relative to, set
the operation's +interval-origin+. The cluster uses this point to
calculate the correct +start-delay+ such that the operation will occur
at _origin + (interval * N)_.
So, if the operation's interval is 24h, its interval-origin is set to
02:00 and it is currently 14:32, then the cluster would initiate
the operation with a start delay of 11 hours and 28 minutes. If the
resource is moved to another node before 2am, then the operation is
cancelled.
The value specified for +interval+ and +interval-origin+ can be any
date/time conforming to the
http://en.wikipedia.org/wiki/ISO_8601[ISO8601 standard]. By way of
example, to specify an operation that would run on the first Monday of
2009 and every Monday after that, you would add:
.Specifying a Base for Recurring Action Intervals
=====
[source,XML]
<op id="my-weekly-action" name="custom-action" interval="P7D" interval-origin="2009-W01-1"/>
=====
[[s-failure-handling]]
== Handling Resource Failure ==
By default, Pacemaker will attempt to recover failed resources by restarting
them. However, failure recovery is highly configurable.
=== Failure Counts ===
Pacemaker tracks resource failures for each combination of node, resource, and
operation (start, stop, monitor, etc.).
You can query the fail count for a particular node, resource, and/or operation
using the `crm_failcount` command. For example, to see how many times the
10-second monitor for +myrsc+ has failed on +node1+, run:
----
# crm_failcount --query -r myrsc -N node1 -n monitor -I 10s
----
If you omit the node, `crm_failcount` will use the local node. If you omit the
operation and interval, `crm_failcount` will display the sum of the fail counts
for all operations on the resource.
You can use `crm_resource --cleanup` or `crm_failcount --delete` to clear
fail counts. For example, to clear the above monitor failures, run:
----
# crm_resource --cleanup -r myrsc -N node1 -n monitor -I 10s
----
If you omit the resource, `crm_resource --cleanup` will clear failures for all
resources. If you omit the node, it will clear failures on all nodes. If you
omit the operation and interval, it will clear the failures for all operations
on the resource.
[NOTE]
====
Even when cleaning up only a single operation, all failed operations will
disappear from the status display. This allows us to trigger a re-check of the
resource's current status.
====
Higher-level tools may provide other commands for querying and clearing
fail counts.
The `crm_mon` tool shows the current cluster status, including any failed
operations. To see the current fail counts for any failed resources, call
`crm_mon` with the `--failcounts` option. This shows the fail counts per
resource (that is, the sum of any operation fail counts for the resource).
=== Failure Response ===
Normally, if a running resource fails, pacemaker will try to stop it and start
it again. Pacemaker will choose the best location to start it each time, which
may be the same node that it failed on.
However, if a resource fails repeatedly, it is possible that there is an
underlying problem on that node, and you might desire trying a different node
in such a case. Pacemaker allows you to set your preference via the
+migration-threshold+ resource meta-attribute.
footnote:[
The naming of this option was perhaps unfortunate as it is easily
confused with live migration, the process of moving a resource from
one node to another without stopping it. Xen virtual guests are the
most common example of resources that can be migrated in this manner.
]
If you define +migration-threshold=pass:[<replaceable>N</replaceable>]+ for a
resource, it will be banned from the original node after 'N' failures.
[NOTE]
====
The +migration-threshold+ is per 'resource', even though fail counts are
tracked per 'operation'. The operation fail counts are added together
to compare against the +migration-threshold+.
====
By default, fail counts remain until manually cleared by an administrator
using `crm_resource --cleanup` or `crm_failcount --delete` (hopefully after
first fixing the failure's cause). It is possible to have fail counts expire
automatically by setting the +failure-timeout+ resource meta-attribute.
[IMPORTANT]
====
A successful operation does not clear past failures. If a recurring monitor
operation fails once, succeeds many times, then fails again days later, its
fail count is 2. Fail counts are cleared only by manual intervention or
falure timeout.
====
For example, a setting of +migration-threshold=2+ and +failure-timeout=60s+
would cause the resource to move to a new node after 2 failures, and
allow it to move back (depending on stickiness and constraint scores) after one
minute.
[NOTE]
====
+failure-timeout+ is measured since the most recent failure. That is, older
failures do not individually time out and lower the fail count. Instead, all
failures are timed out simultaneously (and the fail count is reset to 0) if
there is no new failure for the timeout period.
====
There are two exceptions to the migration threshold concept:
when a resource either fails to start or fails to stop.
If the cluster property +start-failure-is-fatal+ is set to +true+ (which is the
default), start failures cause the fail count to be set to +INFINITY+ and thus
always cause the resource to move immediately.
Stop failures are slightly different and crucial. If a resource fails
to stop and STONITH is enabled, then the cluster will fence the node
in order to be able to start the resource elsewhere. If STONITH is
not enabled, then the cluster has no way to continue and will not try
to start the resource elsewhere, but will try to stop it again after
the failure timeout.
[IMPORTANT]
Please read <<s-rules-recheck>> to understand how timeouts work
before configuring a +failure-timeout+.
== Moving Resources ==
indexterm:[Moving,Resources]
indexterm:[Resource,Moving]
=== Moving Resources Manually ===
There are primarily two occasions when you would want to move a
resource from its current location: when the whole node is under
maintenance, and when a single resource needs to be moved.
==== Standby Mode ====
Since everything eventually comes down to a score, you could create
constraints for every resource to prevent them from running on one
node. While pacemaker configuration can seem convoluted at times, not even
we would require this of administrators.
Instead, one can set a special node attribute which tells the cluster
"don't let anything run here". There is even a helpful tool to help
query and set it, called `crm_standby`. To check the standby status
of the current machine, run:
----
# crm_standby -G
----
A value of +on+ indicates that the node is _not_ able to host any
resources, while a value of +off+ says that it _can_.
You can also check the status of other nodes in the cluster by
specifying the `--node` option:
----
# crm_standby -G --node sles-2
----
To change the current node's standby status, use `-v` instead of `-G`:
----
# crm_standby -v on
----
Again, you can change another host's value by supplying a hostname with `--node`.
==== Moving One Resource ====
When only one resource is required to move, we could do this by creating
location constraints. However, once again we provide a user-friendly
shortcut as part of the `crm_resource` command, which creates and
modifies the extra constraints for you. If +Email+ were running on
+sles-1+ and you wanted it moved to a specific location, the command
would look something like:
----
# crm_resource -M -r Email -H sles-2
----
Behind the scenes, the tool will create the following location constraint:
[source,XML]
<rsc_location rsc="Email" node="sles-2" score="INFINITY"/>
It is important to note that subsequent invocations of `crm_resource
-M` are not cumulative. So, if you ran these commands
----
# crm_resource -M -r Email -H sles-2
# crm_resource -M -r Email -H sles-3
----
then it is as if you had never performed the first command.
To allow the resource to move back again, use:
----
# crm_resource -U -r Email
----
Note the use of the word _allow_. The resource can move back to its
original location but, depending on +resource-stickiness+, it might
stay where it is. To be absolutely certain that it moves back to
+sles-1+, move it there before issuing the call to `crm_resource -U`:
----
# crm_resource -M -r Email -H sles-1
# crm_resource -U -r Email
----
Alternatively, if you only care that the resource should be moved from
its current location, try:
----
# crm_resource -B -r Email
----
Which will instead create a negative constraint, like
[source,XML]
<rsc_location rsc="Email" node="sles-1" score="-INFINITY"/>
This will achieve the desired effect, but will also have long-term
consequences. As the tool will warn you, the creation of a
+-INFINITY+ constraint will prevent the resource from running on that
node until `crm_resource -U` is used. This includes the situation
where every other cluster node is no longer available!
In some cases, such as when +resource-stickiness+ is set to
+INFINITY+, it is possible that you will end up with the problem
described in <<node-score-equal>>. The tool can detect
some of these cases and deals with them by creating both
positive and negative constraints. E.g.
+Email+ prefers +sles-1+ with a score of +-INFINITY+
+Email+ prefers +sles-2+ with a score of +INFINITY+
which has the same long-term consequences as discussed earlier.
=== Moving Resources Due to Connectivity Changes ===
You can configure the cluster to move resources when external connectivity is
lost in two steps.
==== Tell Pacemaker to Monitor Connectivity ====
First, add an *ocf:pacemaker:ping* resource to the cluster. The
*ping* resource uses the system utility of the same name to a test whether
list of machines (specified by DNS hostname or IPv4/IPv6 address) are
reachable and uses the results to maintain a node attribute called +pingd+
by default.
footnote:[
The attribute name is customizable, in order to allow multiple ping groups to be defined.
]
[NOTE]
===========
Older versions of Pacemaker used a different agent *ocf:pacemaker:pingd* which
is now deprecated in favor of *ping*. If your version of Pacemaker does not
contain the *ping* resource agent, download the latest version from
https://github.com/ClusterLabs/pacemaker/tree/master/extra/resources/ping
===========
Normally, the ping resource should run on all cluster nodes, which means that
you'll need to create a clone. A template for this can be found below
along with a description of the most interesting parameters.
.Common Options for a 'ping' Resource
-[width="95%",cols="1m,4<",options="header",align="center"]
+[width="95%",cols="1m,<4",options="header",align="center"]
|=========================================================
|Field
|Description
|dampen
|The time to wait (dampening) for further changes to occur. Use this
to prevent a resource from bouncing around the cluster when cluster
nodes notice the loss of connectivity at slightly different times.
indexterm:[dampen,Ping Resource Option]
indexterm:[Ping Resource,Option,dampen]
|multiplier
|The number of connected ping nodes gets multiplied by this value to
get a score. Useful when there are multiple ping nodes configured.
indexterm:[multiplier,Ping Resource Option]
indexterm:[Ping Resource,Option,multiplier]
|host_list
|The machines to contact in order to determine the current
connectivity status. Allowed values include resolvable DNS host
names, IPv4 and IPv6 addresses.
indexterm:[host_list,Ping Resource Option]
indexterm:[Ping Resource,Option,host_list]
|=========================================================
.An example ping cluster resource that checks node connectivity once every minute
=====
[source,XML]
------------
<clone id="Connected">
<primitive id="ping" provider="pacemaker" class="ocf" type="ping">
<instance_attributes id="ping-attrs">
<nvpair id="pingd-dampen" name="dampen" value="5s"/>
<nvpair id="pingd-multiplier" name="multiplier" value="1000"/>
<nvpair id="pingd-hosts" name="host_list" value="my.gateway.com www.bigcorp.com"/>
</instance_attributes>
<operations>
<op id="ping-monitor-60s" interval="60s" name="monitor"/>
</operations>
</primitive>
</clone>
------------
=====
[IMPORTANT]
===========
You're only half done. The next section deals with telling Pacemaker
how to deal with the connectivity status that +ocf:pacemaker:ping+ is
recording.
===========
==== Tell Pacemaker How to Interpret the Connectivity Data ====
[IMPORTANT]
======
Before attempting the following, make sure you understand
<<ch-rules>>.
======
There are a number of ways to use the connectivity data.
The most common setup is for people to have a single ping
target (e.g. the service network's default gateway), to prevent the cluster
from running a resource on any unconnected node.
.Don't run a resource on unconnected nodes
=====
[source,XML]
-------
<rsc_location id="WebServer-no-connectivity" rsc="Webserver">
<rule id="ping-exclude-rule" score="-INFINITY" >
<expression id="ping-exclude" attribute="pingd" operation="not_defined"/>
</rule>
</rsc_location>
-------
=====
A more complex setup is to have a number of ping targets configured.
You can require the cluster to only run resources on nodes that can
connect to all (or a minimum subset) of them.
.Run only on nodes connected to three or more ping targets.
=====
[source,XML]
-------
<primitive id="ping" provider="pacemaker" class="ocf" type="ping">
... <!-- omitting some configuration to highlight important parts -->
<nvpair id="pingd-multiplier" name="multiplier" value="1000"/>
...
</primitive>
...
<rsc_location id="WebServer-connectivity" rsc="Webserver">
<rule id="ping-prefer-rule" score="-INFINITY" >
<expression id="ping-prefer" attribute="pingd" operation="lt" value="3000"/>
</rule>
</rsc_location>
-------
=====
Alternatively, you can tell the cluster only to _prefer_ nodes with the best
connectivity. Just be sure to set +multiplier+ to a value higher than
that of +resource-stickiness+ (and don't set either of them to
+INFINITY+).
.Prefer the node with the most connected ping nodes
=====
[source,XML]
-------
<rsc_location id="WebServer-connectivity" rsc="Webserver">
<rule id="ping-prefer-rule" score-attribute="pingd" >
<expression id="ping-prefer" attribute="pingd" operation="defined"/>
</rule>
</rsc_location>
-------
=====
It is perhaps easier to think of this in terms of the simple
constraints that the cluster translates it into. For example, if
*sles-1* is connected to all five ping nodes but *sles-2* is only
connected to two, then it would be as if you instead had the following
constraints in your configuration:
.How the cluster translates the above location constraint
=====
[source,XML]
-------
<rsc_location id="ping-1" rsc="Webserver" node="sles-1" score="5000"/>
<rsc_location id="ping-2" rsc="Webserver" node="sles-2" score="2000"/>
-------
=====
The advantage is that you don't have to manually update any
constraints whenever your network connectivity changes.
You can also combine the concepts above into something even more
complex. The example below shows how you can prefer the node with the
most connected ping nodes provided they have connectivity to at least
three (again assuming that +multiplier+ is set to 1000).
.A more complex example of choosing a location based on connectivity
=====
[source,XML]
-------
<rsc_location id="WebServer-connectivity" rsc="Webserver">
<rule id="ping-exclude-rule" score="-INFINITY" >
<expression id="ping-exclude" attribute="pingd" operation="lt" value="3000"/>
</rule>
<rule id="ping-prefer-rule" score-attribute="pingd" >
<expression id="ping-prefer" attribute="pingd" operation="defined"/>
</rule>
</rsc_location>
-------
=====
[[s-migrating-resources]]
=== Migrating Resources ===
Normally, when the cluster needs to move a resource, it fully restarts
the resource (i.e. stops the resource on the current node
and starts it on the new node).
However, some types of resources, such as Xen virtual guests, are able to move to
another location without loss of state (often referred to as live migration
or hot migration). In pacemaker, this is called resource migration.
Pacemaker can be configured to migrate a resource when moving it,
rather than restarting it.
Not all resources are able to migrate; see the Migration Checklist
below, and those that can, won't do so in all situations.
Conceptually, there are two requirements from which the other
prerequisites follow:
* The resource must be active and healthy at the old location; and
* everything required for the resource to run must be available on
both the old and new locations.
The cluster is able to accommodate both 'push' and 'pull' migration models
by requiring the resource agent to support two special actions:
+migrate_to+ (performed on the current location) and +migrate_from+
(performed on the destination).
In push migration, the process on the current location transfers the
resource to the new location where is it later activated. In this
scenario, most of the work would be done in the +migrate_to+ action
and, if anything, the activation would occur during +migrate_from+.
Conversely for pull, the +migrate_to+ action is practically empty and
+migrate_from+ does most of the work, extracting the relevant resource
state from the old location and activating it.
There is no wrong or right way for a resource agent to implement migration,
as long as it works.
.Migration Checklist
* The resource may not be a clone.
* The resource must use an OCF style agent.
* The resource must not be in a failed or degraded state.
* The resource agent must support +migrate_to+ and
+migrate_from+ actions, and advertise them in its metadata.
* The resource must have the +allow-migrate+ meta-attribute set to
+true+ (which is not the default).
If an otherwise migratable resource depends on another resource
via an ordering constraint, there are special situations in which it will be
restarted rather than migrated.
For example, if the resource depends on a clone, and at the time the resource
needs to be moved, the clone has instances that are stopping and instances
that are starting, then the resource will be restarted. The scheduler is not
yet able to model this situation correctly and so takes the safer (if less
optimal) path.
Also, if a migratable resource depends on a non-migratable resource, and both
need to be moved, the migratable resource will be restarted.
[[s-node-health]]
== Tracking Node Health ==
A node may be functioning adequately as far as cluster membership is concerned,
and yet be "unhealthy" in some respect that makes it an undesirable location
for resources. For example, a disk drive may be reporting SMART errors, or the
CPU may be highly loaded.
Pacemaker offers a way to automatically move resources off unhealthy nodes.
=== Node Health Attributes ===
Pacemaker will treat any node attribute whose name starts with +#health+ as an
indicator of node health. Node health attributes may have one of the following
values:
.Allowed Values for Node Health Attributes
-[width="95%",cols="1,3<",options="header",align="center"]
+[width="95%",cols="1,<3",options="header",align="center"]
|=========================================================
|Value
|Intended significance
|+red+
|This indicator is unhealthy
indexterm:[Node health,red]
|+yellow+
|This indicator is becoming unhealthy
indexterm:[Node health,yellow]
|+green+
|This indicator is healthy
indexterm:[Node health,green]
|'integer'
|A numeric score to apply to all resources on this node
(0 or positive is healthy, negative is unhealthy)
indexterm:[Node health,score]
|=========================================================
=== Node Health Strategy ===
Pacemaker assigns a node health score to each node, as the sum of the values of
all its node health attributes. This score will be used as a location
constraint applied to this node for all resources.
The +node-health-strategy+ cluster option controls how Pacemaker responds to
changes in node health attributes, and how it translates +red+, +yellow+, and
+green+ to scores.
Allowed values are:
.Node Health Strategies
-[width="95%",cols="1m,3<",options="header",align="center"]
+[width="95%",cols="1m,<3",options="header",align="center"]
|=========================================================
|Value
|Effect
|none
|Do not track node health attributes at all.
indexterm:[Node health,none]
|migrate-on-red
|Assign the value of +-INFINITY+ to +red+, and 0 to +yellow+ and +green+.
This will cause all resources to move off the node if any attribute is +red+.
indexterm:[Node health,migrate-on-red]
|only-green
|Assign the value of +-INFINITY+ to +red+ and +yellow+, and 0 to +green+.
This will cause all resources to move off the node if any attribute is +red+
or +yellow+.
indexterm:[Node health,only-green]
|progressive
|Assign the value of the +node-health-red+ cluster option to +red+, the value
of +node-health-yellow+ to +yellow+, and the value of +node-health-green+ to
+green+. Each node is additionally assigned a score of +node-health-base+
(this allows resources to start even if some attributes are +yellow+). This
strategy gives the administrator finer control over how important each value
is.
indexterm:[Node health,progressive]
|custom
|Track node health attributes using the same values as +progressive+ for
+red+, +yellow+, and +green+, but do not take them into account.
The administrator is expected to implement a policy by defining rules
(see <<ch-rules>>) referencing node health attributes.
indexterm:[Node health,custom]
|=========================================================
=== Measuring Node Health ===
Since Pacemaker calculates node health based on node attributes,
any method that sets node attributes may be used to measure node
health. The most common ways are resource agents or separate daemons.
Pacemaker provides examples that can be used directly or as a basis for
custom code. The +ocf:pacemaker:HealthCPU+ and +ocf:pacemaker:HealthSMART+
resource agents set node health attributes based on CPU and disk parameters.
The +ipmiservicelogd+ daemon sets node health attributes based on IPMI
values (the +ocf:pacemaker:SystemHealth+ resource agent can be used to manage
the daemon as a cluster resource).
== Reloading Services After a Definition Change ==
The cluster automatically detects changes to the definition of
services it manages. The normal response is to stop the
service (using the old definition) and start it again (with the new
definition). This works well, but some services are smarter and can
be told to use a new set of options without restarting.
To take advantage of this capability, the resource agent must:
. Accept the +reload+ operation and perform any required actions.
_The actions here depend completely on your application!_
+
.The DRBD agent's logic for supporting +reload+
=====
[source,Bash]
-------
case $1 in
start)
drbd_start
;;
stop)
drbd_stop
;;
reload)
drbd_reload
;;
monitor)
drbd_monitor
;;
*)
drbd_usage
exit $OCF_ERR_UNIMPLEMENTED
;;
esac
exit $?
-------
=====
. Advertise the +reload+ operation in the +actions+ section of its metadata
+
.The DRBD Agent Advertising Support for the +reload+ Operation
=====
[source,XML]
-------
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="drbd">
<version>1.1</version>
<longdesc lang="en">
Master/Slave OCF Resource Agent for DRBD
</longdesc>
...
<actions>
<action name="start" timeout="240" />
<action name="reload" timeout="240" />
<action name="promote" timeout="90" />
<action name="demote" timeout="90" />
<action name="notify" timeout="90" />
<action name="stop" timeout="100" />
<action name="meta-data" timeout="5" />
<action name="validate-all" timeout="30" />
</actions>
</resource-agent>
-------
=====
. Advertise one or more parameters that can take effect using +reload+.
+
Any parameter with the +unique+ set to 0 is eligible to be used in this way.
+
.Parameter that can be changed using reload
=====
[source,XML]
-------
<parameter name="drbdconf" unique="0">
<longdesc lang="en">Full path to the drbd.conf file.</longdesc>
<shortdesc lang="en">Path to drbd.conf</shortdesc>
<content type="string" default="${OCF_RESKEY_drbdconf_default}"/>
</parameter>
-------
=====
Once these requirements are satisfied, the cluster will automatically
know to reload the resource (instead of restarting) when a non-unique
field changes.
[NOTE]
======
Metadata will not be re-read unless the resource needs to be started. This may
mean that the resource will be restarted the first time, even though you
changed a parameter with +unique=0+.
======
[NOTE]
======
If both a unique and non-unique field are changed simultaneously, the
resource will still be restarted.
======
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt
index 345ccaa042..4c401d1dd1 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt
@@ -1,1454 +1,1454 @@
= Advanced Resource Types =
[[group-resources]]
== Groups - A Syntactic Shortcut ==
indexterm:[Group Resources]
indexterm:[Resource,Groups]
One of the most common elements of a cluster is a set of resources
that need to be located together, start sequentially, and stop in the
reverse order. To simplify this configuration, we support the concept
of groups.
.A group of two primitive resources
======
[source,XML]
-------
<group id="shortcut">
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
<primitive id="Email" class="lsb" type="exim"/>
</group>
-------
======
Although the example above contains only two resources, there is no
limit to the number of resources a group can contain. The example is
also sufficient to explain the fundamental properties of a group:
* Resources are started in the order they appear in (+Public-IP+
first, then +Email+)
* Resources are stopped in the reverse order to which they appear in
(+Email+ first, then +Public-IP+)
If a resource in the group can't run anywhere, then nothing after that
is allowed to run, too.
* If +Public-IP+ can't run anywhere, neither can +Email+;
* but if +Email+ can't run anywhere, this does not affect +Public-IP+
in any way
The group above is logically equivalent to writing:
.How the cluster sees a group resource
======
[source,XML]
-------
<configuration>
<resources>
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
<primitive id="Email" class="lsb" type="exim"/>
</resources>
<constraints>
<rsc_colocation id="xxx" rsc="Email" with-rsc="Public-IP" score="INFINITY"/>
<rsc_order id="yyy" first="Public-IP" then="Email"/>
</constraints>
</configuration>
-------
======
Obviously as the group grows bigger, the reduced configuration effort
can become significant.
Another (typical) example of a group is a DRBD volume, the filesystem
mount, an IP address, and an application that uses them.
=== Group Properties ===
.Properties of a Group Resource
-[width="95%",cols="3m,5<",options="header",align="center"]
+[width="95%",cols="3m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the group
indexterm:[id,Group Resource Property]
indexterm:[Resource,Group Property,id]
|=========================================================
=== Group Options ===
Groups inherit the +priority+, +target-role+, and +is-managed+ properties
from primitive resources. See <<s-resource-options>> for information about
those properties.
=== Group Instance Attributes ===
Groups have no instance attributes. However, any that are set for the group
object will be inherited by the group's children.
=== Group Contents ===
Groups may only contain a collection of cluster resources (see
<<primitive-resource>>). To refer to a child of a group resource, just use
the child's +id+ instead of the group's.
=== Group Constraints ===
Although it is possible to reference a group's children in
constraints, it is usually preferable to reference the group itself.
.Some constraints involving groups
======
[source,XML]
-------
<constraints>
<rsc_location id="group-prefers-node1" rsc="shortcut" node="node1" score="500"/>
<rsc_colocation id="webserver-with-group" rsc="Webserver" with-rsc="shortcut"/>
<rsc_order id="start-group-then-webserver" first="Webserver" then="shortcut"/>
</constraints>
-------
======
=== Group Stickiness ===
indexterm:[resource-stickiness,Groups]
Stickiness, the measure of how much a resource wants to stay where it
is, is additive in groups. Every active resource of the group will
contribute its stickiness value to the group's total. So if the
default +resource-stickiness+ is 100, and a group has seven members,
five of which are active, then the group as a whole will prefer its
current location with a score of 500.
[[s-resource-clone]]
== Clones - Resources That Can Have Multiple Active Instances ==
indexterm:[Clone Resources]
indexterm:[Resource,Clones]
'Clone' resources are resources that can have more than one copy active at the
same time. This allows you, for example, to run a copy of a daemon on every
node. You can clone any primitive or group resource.
footnote:[
Of course, the service must support running multiple instances.
]
=== Anonymous versus Unique Clones ===
A clone resource is configured to be either 'anonymous' or 'globally unique'.
Anonymous clones are the simplest. These behave completely identically
everywhere they are running. Because of this, there can be only one instance of
an anonymous clone active per node.
The instances of globally unique clones are distinct entities. All instances
are launched identically, but one instance of the clone is not identical to any
other instance, whether running on the same node or a different node. As an
example, a cloned IP address can use special kernel functionality such that
each instance handles a subset of requests for the same IP address.
[[s-resource-promotable]]
=== Promotable clones ===
indexterm:[Promotable Clone Resources]
indexterm:[Resource,Promotable]
If a clone is 'promotable', its instances can perform a special role that
Pacemaker will manage via the +promote+ and +demote+ actions of the resource
agent.
Services that support such a special role have various terms for the special
role and the default role: primary and secondary, master and replica,
controller and worker, etc. Pacemaker uses the terms 'master' and 'slave',
footnote:[
These are historical terms that will eventually be replaced, but the extensive
use of them and the need for backward compatibility makes it a long process.
You may see examples using a +master+ tag instead of a +clone+ tag with the
+promotable+ meta-attribute set to +true+; the +master+ tag is supported, but
deprecated, and will be removed in a future version. You may also see such
services referred to as 'multi-state' or 'stateful'; these means the same thing
as 'promotable'.
]
but is agnostic to what the service calls them or what they do.
All that Pacemaker cares about is that an instance comes up in the default role
when started, and the resource agent supports the +promote+ and +demote+ actions
to manage entering and exiting the special role.
=== Clone Properties ===
.Properties of a Clone Resource
-[width="95%",cols="3m,5<",options="header",align="center"]
+[width="95%",cols="3m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the clone
indexterm:[id,Clone Property]
indexterm:[Clone,Property,id]
|=========================================================
=== Clone Options ===
<<s-resource-options,Options>> inherited from primitive resources:
+priority, target-role, is-managed+
.Clone-specific configuration options
-[width="95%",cols="1m,1,3<",options="header",align="center"]
+[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|globally-unique
|false
|If +true+, each clone instance performs a distinct function
indexterm:[globally-unique,Clone Option]
indexterm:[Clone,Option,globally-unique]
|clone-max
|number of nodes in cluster
|The maximum number of clone instances that can be started across the entire
cluster
indexterm:[clone-max,Clone Option]
indexterm:[Clone,Option,clone-max]
|clone-node-max
|1
|If +globally-unique+ is +true+, the maximum number of clone instances that can
be started on a single node
indexterm:[clone-node-max,Clone Option]
indexterm:[Clone,Option,clone-node-max]
|clone-min
|0
|Require at least this number of clone instances to be runnable before allowing
resources depending on the clone to be runnable. A value of 0 means require
all clone instances to be runnable.
indexterm:[clone-min,Clone Option]
indexterm:[Clone,Option,clone-min]
|notify
|false
|Call the resource agent's +notify+ action for all active instances, before and
after starting or stopping any clone instance. The resource agent must support
this action. Allowed values: +false+, +true+
indexterm:[notify,Clone Option]
indexterm:[Clone,Option,notify]
|ordered
|false
|If +true+, clone instances must be started sequentially instead of in parallel
Allowed values: +false+, +true+
indexterm:[ordered,Clone Option]
indexterm:[Clone,Option,ordered]
|interleave
|false
|When this clone is ordered relative to another clone, if this option is
+false+ (the default), the ordering is relative to 'all' instances of the
other clone, whereas if this option is +true+, the ordering is relative only
to instances on the same node.
Allowed values: +false+, +true+
indexterm:[interleave,Clone Option]
indexterm:[Clone,Option,interleave]
|promotable
|false
|If +true+, clone instances can perform a special role that Pacemaker will
manage via the resource agent's +promote+ and +demote+ actions. The resource
agent must support these actions.
Allowed values: +false+, +true+
indexterm:[promotable,Clone Option]
indexterm:[Clone,Option,promotable]
|promoted-max
|1
|If +promotable+ is +true+, the number of instances that can be promoted at one
time across the entire cluster
indexterm:[promoted-max,Clone Option]
indexterm:[Clone,Option,promoted-max]
|promoted-node-max
|1
|If +promotable+ is +true+ and +globally-unique+ is +false+, the number of
clone instances can be promoted at one time on a single node
indexterm:[promoted-node-max,Clone Option]
indexterm:[Clone,Option,promoted-node-max]
|=========================================================
For backward compatibility, +master-max+ and +master-node-max+ are accepted as
aliases for +promoted-max+ and +promoted-node-max+, but are deprecated since
2.0.0, and support for them will be removed in a future version.
=== Clone Contents ===
Clones must contain exactly one primitive or group resource.
.A clone that runs a web server on all nodes
====
[source,XML]
----
<clone id="apache-clone">
<primitive id="apache" class="lsb" type="apache">
<operations>
<op id="apache-monitor" name="monitor" interval="30"/>
</operations>
</primitive>
</clone>
----
====
[WARNING]
You should never reference the name of a clone's child (the primitive or group
resource being cloned). If you think you need to do this, you probably need to
re-evaluate your design.
=== Clone Instance Attributes ===
Clones have no instance attributes; however, any that are set here will be
inherited by the clone's child.
=== Clone Constraints ===
In most cases, a clone will have a single instance on each active cluster
node. If this is not the case, you can indicate which nodes the
cluster should preferentially assign copies to with resource location
constraints. These constraints are written no differently from those
for primitive resources except that the clone's +id+ is used.
.Some constraints involving clones
======
[source,XML]
-------
<constraints>
<rsc_location id="clone-prefers-node1" rsc="apache-clone" node="node1" score="500"/>
<rsc_colocation id="stats-with-clone" rsc="apache-stats" with="apache-clone"/>
<rsc_order id="start-clone-then-stats" first="apache-clone" then="apache-stats"/>
</constraints>
-------
======
Ordering constraints behave slightly differently for clones. In the
example above, +apache-stats+ will wait until all copies of +apache-clone+
that need to be started have done so before being started itself.
Only if _no_ copies can be started will +apache-stats+ be prevented
from being active. Additionally, the clone will wait for
+apache-stats+ to be stopped before stopping itself.
Colocation of a primitive or group resource with a clone means that
the resource can run on any node with an active instance of the clone.
The cluster will choose an instance based on where the clone is running and
the resource's own location preferences.
Colocation between clones is also possible. If one clone +A+ is colocated
with another clone +B+, the set of allowed locations for +A+ is limited to
nodes on which +B+ is (or will be) active. Placement is then performed
normally.
==== Promotable Clone Constraints ====
For promotable clone resources, the +first-action+ and/or +then-action+ fields
for ordering constraints may be set to +promote+ or +demote+ to constrain the
master role, and colocation constraints may contain +rsc-role+ and/or
+with-rsc-role+ fields.
.Additional colocation constraint options for promotable clone resources
-[width="95%",cols="1m,1,3<",options="header",align="center"]
+[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|rsc-role
|Started
|An additional attribute of colocation constraints that specifies the
role that +rsc+ must be in. Allowed values: +Started+, +Master+,
+Slave+.
indexterm:[rsc-role,Ordering Constraints]
indexterm:[Constraints,Ordering,rsc-role]
|with-rsc-role
|Started
|An additional attribute of colocation constraints that specifies the
role that +with-rsc+ must be in. Allowed values: +Started+,
+Master+, +Slave+.
indexterm:[with-rsc-role,Ordering Constraints]
indexterm:[Constraints,Ordering,with-rsc-role]
|=========================================================
.Constraints involving promotable clone resources
======
[source,XML]
-------
<constraints>
<rsc_location id="db-prefers-node1" rsc="database" node="node1" score="500"/>
<rsc_colocation id="backup-with-db-slave" rsc="backup"
with-rsc="database" with-rsc-role="Slave"/>
<rsc_colocation id="myapp-with-db-master" rsc="myApp"
with-rsc="database" with-rsc-role="Master"/>
<rsc_order id="start-db-before-backup" first="database" then="backup"/>
<rsc_order id="promote-db-then-app" first="database" first-action="promote"
then="myApp" then-action="start"/>
</constraints>
-------
======
In the example above, +myApp+ will wait until one of the database
copies has been started and promoted to master before being started
itself on the same node. Only if no copies can be promoted will +myApp+ be
prevented from being active. Additionally, the cluster will wait for
+myApp+ to be stopped before demoting the database.
Colocation of a primitive or group resource with a promotable clone
resource means that it can run on any node with an active instance of
the promotable clone resource that has the specified role (+master+ or
+slave+). In the example above, the cluster will choose a location based on
where database is running as a +master+, and if there are multiple
+master+ instances it will also factor in +myApp+'s own location
preferences when deciding which location to choose.
Colocation with regular clones and other promotable clone resources is also
possible. In such cases, the set of allowed locations for the +rsc+
clone is (after role filtering) limited to nodes on which the
+with-rsc+ promotable clone resource is (or will be) in the specified role.
Placement is then performed as normal.
==== Using Promotable Clone Resources in Colocation Sets ====
.Additional colocation set options relevant to promotable clone resources
-[width="95%",cols="1m,1,6<",options="header",align="center"]
+[width="95%",cols="1m,1,<6",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|role
|Started
|The role that 'all members' of the set must be in. Allowed values: +Started+, +Master+,
+Slave+.
indexterm:[role,Ordering Constraints]
indexterm:[Constraints,Ordering,role]
|=========================================================
In the following example +B+'s master must be located on the same node as +A+'s master.
Additionally resources +C+ and +D+ must be located on the same node as +A+'s
and +B+'s masters.
.Colocate C and D with A's and B's master instances
======
[source,XML]
-------
<constraints>
<rsc_colocation id="coloc-1" score="INFINITY" >
<resource_set id="colocated-set-example-1" sequential="true" role="Master">
<resource_ref id="A"/>
<resource_ref id="B"/>
</resource_set>
<resource_set id="colocated-set-example-2" sequential="true">
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
</rsc_colocation>
</constraints>
-------
======
==== Using Promotable Clone Resources in Ordered Sets ====
.Additional ordered set options relevant to promotable clone resources
-[width="95%",cols="1m,1,3<",options="header",align="center"]
+[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|action
|value of +first-action+
|An additional attribute of ordering constraint sets that specifies the
action that applies to 'all members' of the set. Allowed
values: +start+, +stop+, +promote+, +demote+.
indexterm:[action,Ordering Constraints]
indexterm:[Constraints,Ordering,action]
|=========================================================
.Start C and D after first promoting A and B
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1" score="INFINITY" >
<resource_set id="ordered-set-1" sequential="true" action="promote">
<resource_ref id="A"/>
<resource_ref id="B"/>
</resource_set>
<resource_set id="ordered-set-2" sequential="true" action="start">
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
</rsc_order>
</constraints>
-------
======
In the above example, +B+ cannot be promoted to a master role until +A+ has
been promoted. Additionally, resources +C+ and +D+ must wait until +A+ and +B+
have been promoted before they can start.
[[s-clone-stickiness]]
=== Clone Stickiness ===
indexterm:[resource-stickiness,Clones]
To achieve a stable allocation pattern, clones are slightly sticky by
default. If no value for +resource-stickiness+ is provided, the clone
will use a value of 1. Being a small value, it causes minimal
disturbance to the score calculations of other resources but is enough
to prevent Pacemaker from needlessly moving copies around the cluster.
[NOTE]
====
For globally unique clones, this may result in multiple instances of the
clone staying on a single node, even after another eligible node becomes
active (for example, after being put into standby mode then made active again).
If you do not want this behavior, specify a +resource-stickiness+ of 0
for the clone temporarily and let the cluster adjust, then set it back
to 1 if you want the default behavior to apply again.
====
=== Clone Resource Agent Requirements ===
Any resource can be used as an anonymous clone, as it requires no
additional support from the resource agent. Whether it makes sense to
do so depends on your resource and its resource agent.
==== Resource Agent Requirements for Globally Unique Clones ====
Globally unique clones require additional support in the resource agent. In
particular, it must only respond with +$\{OCF_SUCCESS}+ if the node has that
exact instance active. All other probes for instances of the clone should
result in +$\{OCF_NOT_RUNNING}+ (or one of the other OCF error codes if
they are failed).
Individual instances of a clone are identified by appending a colon and a
numerical offset, e.g. +apache:2+.
Resource agents can find out how many copies there are by examining
the +OCF_RESKEY_CRM_meta_clone_max+ environment variable and which
instance it is by examining +OCF_RESKEY_CRM_meta_clone+.
The resource agent must not make any assumptions (based on
+OCF_RESKEY_CRM_meta_clone+) about which numerical instances are active. In
particular, the list of active copies will not always be an unbroken
sequence, nor always start at 0.
==== Resource Agent Requirements for Promotable Clones ====
Promotable clone resources require two extra actions, +demote+ and +promote+,
which are responsible for changing the state of the resource. Like +start+ and
+stop+, they should return +$\{OCF_SUCCESS}+ if they completed successfully or
a relevant error code if they did not.
The states can mean whatever you wish, but when the resource is
started, it must come up in the mode called +slave+. From there the
cluster will decide which instances to promote to +master+.
In addition to the clone requirements for monitor actions, agents must
also _accurately_ report which state they are in. The cluster relies
on the agent to report its status (including role) accurately and does
not indicate to the agent what role it currently believes it to be in.
.Role implications of OCF return codes
-[width="95%",cols="1,1<",options="header",align="center"]
+[width="95%",cols="1,<1",options="header",align="center"]
|=========================================================
|Monitor Return Code
|Description
|OCF_NOT_RUNNING
|Stopped
indexterm:[Return Code,OCF_NOT_RUNNING]
|OCF_SUCCESS
|Running (Slave)
indexterm:[Return Code,OCF_SUCCESS]
|OCF_RUNNING_MASTER
|Running (Master)
indexterm:[Return Code,OCF_RUNNING_MASTER]
|OCF_FAILED_MASTER
|Failed (Master)
indexterm:[Return Code,OCF_FAILED_MASTER]
|Other
|Failed (Slave)
|=========================================================
==== Clone Notifications ====
If the clone has the +notify+ meta-attribute set to +true+, and the resource
agent supports the +notify+ action, Pacemaker will call the action when
appropriate, passing a number of extra variables which, when combined with
additional context, can be used to calculate the current state of the cluster
and what is about to happen to it.
.Environment variables supplied with Clone notify actions
-[width="95%",cols="5,3<",options="header",align="center"]
+[width="95%",cols="5,<3",options="header",align="center"]
|=========================================================
|Variable
|Description
|OCF_RESKEY_CRM_meta_notify_type
|Allowed values: +pre+, +post+
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,type]
indexterm:[type,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_operation
|Allowed values: +start+, +stop+
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,operation]
indexterm:[operation,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_start_resource
|Resources to be started
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_resource]
indexterm:[start_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_stop_resource
|Resources to be stopped
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_resource]
indexterm:[stop_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_active_resource
|Resources that are running
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_resource]
indexterm:[active_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_inactive_resource
|Resources that are not running
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,inactive_resource]
indexterm:[inactive_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_start_uname
|Nodes on which resources will be started
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_uname]
indexterm:[start_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_stop_uname
|Nodes on which resources will be stopped
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_uname]
indexterm:[stop_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_active_uname
|Nodes on which resources are running
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_uname]
indexterm:[active_uname,Notification Environment Variable]
|=========================================================
The variables come in pairs, such as
+OCF_RESKEY_CRM_meta_notify_start_resource+ and
+OCF_RESKEY_CRM_meta_notify_start_uname+ and should be treated as an
array of whitespace-separated elements.
+OCF_RESKEY_CRM_meta_notify_inactive_resource+ is an exception as the
matching +uname+ variable does not exist since inactive resources
are not running on any node.
Thus in order to indicate that +clone:0+ will be started on +sles-1+,
+clone:2+ will be started on +sles-3+, and +clone:3+ will be started
on +sles-2+, the cluster would set
.Notification variables
======
[source,Bash]
-------
OCF_RESKEY_CRM_meta_notify_start_resource="clone:0 clone:2 clone:3"
OCF_RESKEY_CRM_meta_notify_start_uname="sles-1 sles-3 sles-2"
-------
======
==== Interpretation of Notification Variables ====
.Pre-notification (stop):
* Active resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+
* Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (stop) / Pre-notification (start):
* Active resources
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Inactive resources
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (start):
* Active resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
==== Extra Notifications for Promotable Clones ====
.Extra environment variables supplied for promotable clones
-[width="95%",cols="5,3<",options="header",align="center"]
+[width="95%",cols="5,<3",options="header",align="center"]
|=========================================================
|_OCF_RESKEY_CRM_meta_notify_master_resource_
|Resources that are running in +Master+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,master_resource]
indexterm:[master_resource,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_slave_resource_
|Resources that are running in +Slave+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,slave_resource]
indexterm:[slave_resource,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_promote_resource_
|Resources to be promoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,promote_resource]
indexterm:[promote_resource,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_demote_resource_
|Resources to be demoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,demote_resource]
indexterm:[demote_resource,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_promote_uname_
|Nodes on which resources will be promoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,promote_uname]
indexterm:[promote_uname,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_demote_uname_
|Nodes on which resources will be demoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,demote_uname]
indexterm:[demote_uname,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_master_uname_
|Nodes on which resources are running in +Master+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,master_uname]
indexterm:[master_uname,Notification Environment Variable]
|_OCF_RESKEY_CRM_meta_notify_slave_uname_
|Nodes on which resources are running in +Slave+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,slave_uname]
indexterm:[slave_uname,Notification Environment Variable]
|=========================================================
==== Interpretation of Promotable Notification Variables ====
.Pre-notification (demote):
* +Active+ resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+
* +Master+ resources: +$OCF_RESKEY_CRM_meta_notify_master_resource+
* +Slave+ resources: +$OCF_RESKEY_CRM_meta_notify_slave_resource+
* Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (demote) / Pre-notification (stop):
* +Active+ resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* +Slave+ resources: +$OCF_RESKEY_CRM_meta_notify_slave_resource+
* Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
.Post-notification (stop) / Pre-notification (start)
* +Active+ resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* +Slave+ resources:
** +$OCF_RESKEY_CRM_meta_notify_slave_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (start) / Pre-notification (promote)
* +Active+ resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* +Slave+ resources:
** +$OCF_RESKEY_CRM_meta_notify_slave_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (promote)
* +Active+ resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* +Slave+ resources:
** +$OCF_RESKEY_CRM_meta_notify_slave_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
=== Monitoring Promotable Clone Resources ===
The usual monitor actions are insufficient to monitor a promotable clone
resource, because Pacemaker needs to verify not only that the resource is
active, but also that its actual role matches its intended one.
Define two monitoring actions: the usual one will cover the slave role,
and an additional one with +role="master"+ will cover the master role.
.Monitoring both states of a promotable clone resource
======
[source,XML]
-------
<clone id="myMasterRsc">
<meta_attributes id="myMasterRsc-meta">
<nvpair name="promotable" value="true"/>
</meta_attributes>
<primitive id="myRsc" class="ocf" type="myApp" provider="myCorp">
<operations>
<op id="public-ip-slave-check" name="monitor" interval="60"/>
<op id="public-ip-master-check" name="monitor" interval="61" role="Master"/>
</operations>
</primitive>
</clone>
-------
======
[IMPORTANT]
===========
It is crucial that _every_ monitor operation has a different interval!
Pacemaker currently differentiates between operations
only by resource and interval; so if (for example) a promotable clone resource
had the same monitor interval for both roles, Pacemaker would ignore the
role when checking the status -- which would cause unexpected return
codes, and therefore unnecessary complications.
===========
[[s-promotion-scores]]
=== Determining Which Instance is Promoted ===
Pacemaker can choose a promotable clone instance to be promoted in one of two
ways:
* Promotion scores: These are node attributes set via the `crm_master` utility,
which generally would be called by the resource agent's start action if it
supports promotable clones. This tool automatically detects both the resource
and host, and should be used to set a preference for being promoted. Based on
this, +promoted-max+, and +promoted-node-max+, the instance(s) with the
highest preference will be promoted.
* Constraints: Location constraints can indicate which nodes are most preferred
as masters.
.Explicitly preferring node1 to be promoted to master
======
[source,XML]
-------
<rsc_location id="master-location" rsc="myMasterRsc">
<rule id="master-rule" score="100" role="Master">
<expression id="master-exp" attribute="#uname" operation="eq" value="node1"/>
</rule>
</rsc_location>
-------
======
[[s-resource-bundle]]
== Bundles - Isolated Environments ==
indexterm:[bundle]
indexterm:[Resource,bundle]
indexterm:[Docker,bundle]
indexterm:[rkt,bundle]
Pacemaker supports a special syntax for launching a
https://en.wikipedia.org/wiki/Operating-system-level_virtualization[container]
with any infrastructure it requires: the 'bundle'.
Pacemaker bundles support https://www.docker.com/[Docker] and
https://coreos.com/rkt/[rkt] container technologies.
footnote:[Docker is a trademark of Docker, Inc. No endorsement by or
association with Docker, Inc. is implied.]
.A bundle for a containerized web server
====
[source,XML]
----
<bundle id="httpd-bundle">
<docker image="pcmk:http" replicas="3"/>
<network ip-range-start="192.168.122.131"
host-netmask="24"
host-interface="eth0">
<port-mapping id="httpd-port" port="80"/>
</network>
<storage>
<storage-mapping id="httpd-syslog"
source-dir="/dev/log"
target-dir="/dev/log"
options="rw"/>
<storage-mapping id="httpd-root"
source-dir="/srv/html"
target-dir="/var/www/html"
options="rw"/>
<storage-mapping id="httpd-logs"
source-dir-root="/var/log/pacemaker/bundles"
target-dir="/etc/httpd/logs"
options="rw"/>
</storage>
<primitive class="ocf" id="httpd" provider="heartbeat" type="apache"/>
</bundle>
----
====
=== Bundle Properties ===
.Properties of a Bundle
-[width="95%",cols="3m,5<",options="header",align="center"]
+[width="95%",cols="3m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the bundle (required)
indexterm:[id,bundle]
indexterm:[bundle,Property,id]
|description
|Arbitrary text (not used by Pacemaker)
indexterm:[description,bundle]
indexterm:[bundle,Property,description]
|=========================================================
A bundle must contain exactly one +<docker>+ or +<rkt>+ element.
=== Docker Properties ===
Before configuring a Docker bundle in Pacemaker, the user must install Docker
and supply a fully configured Docker image on every node allowed to run the
bundle.
Pacemaker will create an implicit +ocf:heartbeat:docker+ resource to manage
a bundle's Docker container. The user must ensure that resource agent is
installed on every node allowed to run the bundle.
.Properties of a Bundle's Docker Element
-[width="95%",cols="3m,4,5<",options="header",align="center"]
+[width="95%",cols="3m,4,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|image
|
|Docker image tag (required)
indexterm:[image,Docker]
indexterm:[Docker,Property,image]
|replicas
|Value of +promoted-max+ if that is positive, else 1
|A positive integer specifying the number of container instances to launch
indexterm:[replicas,Docker]
indexterm:[Docker,Property,replicas]
|replicas-per-host
|1
|A positive integer specifying the number of container instances allowed to run
on a single node
indexterm:[replicas-per-host,Docker]
indexterm:[Docker,Property,replicas-per-host]
|promoted-max
|0
|A non-negative integer that, if positive, indicates that the containerized
service should be treated as a promotable service, with this many replicas
allowed to run the service in the master role
indexterm:[promoted-max,Docker]
indexterm:[Docker,Property,promoted-max]
|network
|
|If specified, this will be passed to +docker run+ as the
https://docs.docker.com/engine/reference/run/#network-settings[network setting]
for the Docker container.
indexterm:[network,Docker]
indexterm:[Docker,Property,network]
|run-command
|`/usr/sbin/pacemaker-remoted` if bundle contains a +primitive+, otherwise none
|This command will be run inside the container when launching it ("PID 1"). If
the bundle contains a +primitive+, this command 'must' start pacemaker-remoted
(but could, for example, be a script that does other stuff, too). If the
container image has a pre-2.0.0 version of Pacemaker, set this to
+/usr/sbin/pacemaker_remoted+ (note the underbar instead of dash).
indexterm:[run-command,Docker]
indexterm:[Docker,Property,run-command]
|options
|
|Extra command-line options to pass to `docker run`
indexterm:[options,Docker]
indexterm:[Docker,Property,options]
|=========================================================
For backward compatibility, +masters+ is accepted as an alias for
+promoted-max+, but is deprecated since 2.0.0, and support for it will be
removed in a future version.
=== rkt Properties ===
Before configuring a rkt bundle in Pacemaker, the user must install rkt
and supply a fully configured container image on every node allowed to run the
bundle.
Pacemaker will create an implicit +ocf:heartbeat:rkt+ resource to manage
a bundle's rkt container. The user must ensure that resource agent is
installed on every node allowed to run the bundle.
.Properties of a Bundle's rkt Element
-[width="95%",cols="3m,4,5<",options="header",align="center"]
+[width="95%",cols="3m,4,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|image
|
|Container image tag (required)
indexterm:[image,rkt]
indexterm:[rkt,Property,image]
|replicas
|Value of +promoted-max+ if that is positive, else 1
|A positive integer specifying the number of container instances to launch
indexterm:[replicas,rkt]
indexterm:[rkt,Property,replicas]
|replicas-per-host
|1
|A positive integer specifying the number of container instances allowed to run
on a single node
indexterm:[replicas-per-host,rkt]
indexterm:[rkt,Property,replicas-per-host]
|promoted-max
|0
|A non-negative integer that, if positive, indicates that the containerized
service should be treated as a promotable service, with this many replicas
allowed to run the service in the master role
indexterm:[promoted-max,rkt]
indexterm:[rkt,Property,promoted-max]
|network
|
|If specified, this will be passed to +rkt run+ as the
network setting for the rkt container.
indexterm:[network,rkt]
indexterm:[rkt,Property,network]
|run-command
|`/usr/sbin/pacemaker-remoted` if bundle contains a +primitive+, otherwise none
|This command will be run inside the container when launching it ("PID 1"). If
the bundle contains a +primitive+, this command 'must' start pacemaker-remoted
(but could, for example, be a script that does other stuff, too). If the
container image has a pre-2.0.0 version of Pacemaker, set this to
+/usr/sbin/pacemaker_remoted+ (note the underbar instead of dash).
indexterm:[run-command,rkt]
indexterm:[rkt,Property,run-command]
|options
|
|Extra command-line options to pass to `rkt run`
indexterm:[options,rkt]
indexterm:[rkt,Property,options]
|=========================================================
For backward compatibility, +masters+ is accepted as an alias for
+promoted-max+, but is deprecated since 2.0.0, and support for it will be
removed in a future version.
=== Bundle Network Properties ===
A bundle may optionally contain one +<network>+ element.
indexterm:[bundle,network]
.Properties of a Bundle's Network Element
-[width="95%",cols="2m,1,4<",options="header",align="center"]
+[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|add-host
|TRUE
|If TRUE, and +ip-range-start+ is used, Pacemaker will automatically ensure
that +/etc/hosts+ inside the containers has entries for each
<<s-resource-bundle-note-replica-names,replica name>> and its assigned IP.
indexterm:[add-host,network]
indexterm:[network,Property,add-host]
|ip-range-start
|
|If specified, Pacemaker will create an implicit +ocf:heartbeat:IPaddr2+
resource for each container instance, starting with this IP address,
using up to +replicas+ sequential addresses. These addresses can be used
from the host's network to reach the service inside the container, though
it is not visible within the container itself. Only IPv4 addresses are
currently supported.
indexterm:[ip-range-start,network]
indexterm:[network,Property,ip-range-start]
|host-netmask
|32
|If +ip-range-start+ is specified, the IP addresses are created with this
CIDR netmask (as a number of bits).
indexterm:[host-netmask,network]
indexterm:[network,Property,host-netmask]
|host-interface
|
|If +ip-range-start+ is specified, the IP addresses are created on this
host interface (by default, it will be determined from the IP address).
indexterm:[host-interface,network]
indexterm:[network,Property,host-interface]
|control-port
|3121
|If the bundle contains a +primitive+, the cluster will use this integer TCP
port for communication with Pacemaker Remote inside the container. Changing
this is useful when the container is unable to listen on the default port,
for example, when the container uses the host's network rather than
+ip-range-start+ (in which case +replicas-per-host+ must be 1), or when the
bundle may run on a Pacemaker Remote node that is already listening on the
default port. Any PCMK_remote_port environment variable set on the host or in
the container is ignored for bundle connections.
indexterm:[control-port,network]
indexterm:[network,Property,control-port]
|=========================================================
[[s-resource-bundle-note-replica-names]]
[NOTE]
====
Replicas are named by the bundle id plus a dash and an integer counter starting
with zero. For example, if a bundle named +httpd-bundle+ has +replicas=2+, its
containers will be named +httpd-bundle-0+ and +httpd-bundle-1+.
====
Additionally, a +<network>+ element may optionally contain one or more
+<port-mapping>+ elements.
indexterm:[bundle,network,port-mapping]
.Properties of a Bundle's Port-Mapping Element
-[width="95%",cols="2m,1,4<",options="header",align="center"]
+[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the port mapping (required)
indexterm:[id,port-mapping]
indexterm:[port-mapping,Property,id]
|port
|
|If this is specified, connections to this TCP port number on the host network
(on the container's assigned IP address, if +ip-range-start+ is specified)
will be forwarded to the container network. Exactly one of +port+ or +range+
must be specified in a +port-mapping+.
indexterm:[port,port-mapping]
indexterm:[port-mapping,Property,port]
|internal-port
|value of +port+
|If +port+ and this are specified, connections to +port+ on the host's network
will be forwarded to this port on the container network.
indexterm:[internal-port,port-mapping]
indexterm:[port-mapping,Property,internal-port]
|range
|
|If this is specified, connections to these TCP port numbers (expressed as
'first_port'-'last_port') on the host network (on the container's assigned IP
address, if +ip-range-start+ is specified) will be forwarded to the same ports
in the container network. Exactly one of +port+ or +range+ must be specified
in a +port-mapping+.
indexterm:[range,port-mapping]
indexterm:[port-mapping,Property,range]
|=========================================================
[NOTE]
====
If the bundle contains a +primitive+, Pacemaker will automatically map the
+control-port+, so it is not necessary to specify that port in a
+port-mapping+.
====
=== Bundle Storage Properties ===
A bundle may optionally contain one +<storage>+ element. A +<storage>+ element
has no properties of its own, but may contain one or more +<storage-mapping>+
elements.
indexterm:[bundle,storage,storage-mapping]
.Properties of a Bundle's Storage-Mapping Element
-[width="95%",cols="2m,1,4<",options="header",align="center"]
+[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the storage mapping (required)
indexterm:[id,storage-mapping]
indexterm:[storage-mapping,Property,id]
|source-dir
|
|The absolute path on the host's filesystem that will be mapped into the
container. Exactly one of +source-dir+ and +source-dir-root+ must be specified
in a +storage-mapping+.
indexterm:[source-dir,storage-mapping]
indexterm:[storage-mapping,Property,source-dir]
|source-dir-root
|
|The start of a path on the host's filesystem that will be mapped into the
container, using a different subdirectory on the host for each container
instance. The subdirectory will be named the same as the
<<s-resource-bundle-note-replica-names,replica name>>.
Exactly one of +source-dir+ and +source-dir-root+ must be specified in a
+storage-mapping+.
indexterm:[source-dir-root,storage-mapping]
indexterm:[storage-mapping,Property,source-dir-root]
|target-dir
|
|The path name within the container where the host storage will be mapped
(required)
indexterm:[target-dir,storage-mapping]
indexterm:[storage-mapping,Property,target-dir]
|options
|
|File system mount options to use when mapping the storage
indexterm:[options,storage-mapping]
indexterm:[storage-mapping,Property,options]
|=========================================================
[NOTE]
====
Pacemaker does not define the behavior if the source directory does not already
exist on the host. However, it is expected that the container technology and/or
its resource agent will create the source directory in that case.
====
[NOTE]
====
If the bundle contains a +primitive+,
Pacemaker will automatically map the equivalent of
+source-dir=/etc/pacemaker/authkey target-dir=/etc/pacemaker/authkey+
and +source-dir-root=/var/log/pacemaker/bundles target-dir=/var/log+ into the
container, so it is not necessary to specify those paths in a
+storage-mapping+.
====
[IMPORTANT]
====
The +PCMK_authkey_location+ environment variable must not be set to anything
other than the default of `/etc/pacemaker/authkey` on any node in the cluster.
====
=== Bundle Primitive ===
A bundle may optionally contain one +<primitive>+ resource
(see <<s-resource-primitive>>). The primitive may have operations,
instance attributes and meta-attributes defined, as usual.
If a bundle contains a primitive resource, the container image must include
the Pacemaker Remote daemon, and at least one of +ip-range-start+ or
+control-port+ must be configured in the bundle. Pacemaker will create an
implicit +ocf:pacemaker:remote+ resource for the connection, launch
Pacemaker Remote within the container, and monitor and manage the primitive
resource via Pacemaker Remote.
If the bundle has more than one container instance (replica), the primitive
resource will function as an implicit clone (see <<s-resource-clone>>) --
a promotable clone if the bundle has +masters+ greater than zero
(see <<s-resource-promotable>>).
[IMPORTANT]
====
Containers in bundles with a +primitive+ must have an accessible networking
environment, so that Pacemaker on the cluster nodes can contact
Pacemaker Remote inside the container. For example, the Docker option
`--net=none` should not be used with a +primitive+. The default (using a
distinct network space inside the container) works in combination with
+ip-range-start+. If the Docker option `--net=host` is used (making the
container share the host's network space), a unique +control-port+ should be
specified for each bundle. Any firewall must allow access to the
+control-port+.
====
[[s-bundle-attributes]]
=== Bundle Node Attributes ===
If the bundle has a +primitive+, the primitive's resource agent may want to set
node attributes such as <<s-promotion-scores,promotion scores>>. However, with
containers, it is not apparent which node should get the attribute.
If the container uses shared storage that is the same no matter which node the
container is hosted on, then it is appropriate to use the promotion score on the
bundle node itself.
On the other hand, if the container uses storage exported from the underlying host,
then it may be more appropriate to use the promotion score on the underlying host.
Since this depends on the particular situation, the
+container-attribute-target+ resource meta-attribute allows the user to specify
which approach to use. If it is set to +host+, then user-defined node attributes
will be checked on the underlying host. If it is anything else, the local node
(in this case the bundle node) is used as usual.
This only applies to user-defined attributes; the cluster will always check the
local node for cluster-defined attributes such as +#uname+.
If +container-attribute-target+ is +host+, the cluster will pass additional
environment variables to the primitive's resource agent that allow it to set
node attributes appropriately: +CRM_meta_container_attribute_target+ (identical
to the meta-attribute value) and +CRM_meta_physical_host+ (the name of the
underlying host).
[NOTE]
====
When called by a resource agent, the attrd_updater and crm_attribute commands
will automatically check those environment variables and set attributes
appropriately.
====
=== Bundle Meta-Attributes ===
Any meta-attribute set on a bundle will be inherited by the bundle's
primitive and any resources implicitly created by Pacemaker for the bundle.
This includes options such as +priority+, +target-role+, and +is-managed+. See
<<s-resource-options>> for more information.
=== Limitations of Bundles ===
Restarting pacemaker while a bundle is unmanaged or the cluster is in
maintenance mode may cause the bundle to fail.
Bundles may not be explicitly cloned or included in groups. This includes the
bundle's primitive and any resources implicitly created by Pacemaker for the
bundle. (If +replicas+ is greater than 1, the bundle will behave like a clone
implicitly.)
Bundles do not have instance attributes, utilization attributes, or operations,
though a bundle's primitive may have them.
A bundle with a primitive can run on a Pacemaker Remote node only if the bundle
uses a distinct +control-port+.
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Alerts.txt b/doc/Pacemaker_Explained/en-US/Ch-Alerts.txt
index afc6d1b553..34daeece5f 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Alerts.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Alerts.txt
@@ -1,423 +1,423 @@
= Alerts =
////
We prefer [[ch-alerts]], but older versions of asciidoc don't deal well
with that construct for chapter headings
////
anchor:ch-alerts[Chapter 7, Alerts]
indexterm:[Resource,Alerts]
'Alerts' may be configured to take some external action when a cluster event
occurs (node failure, resource starting or stopping, etc.).
== Alert Agents ==
As with resource agents, the cluster calls an external program (an
'alert agent') to handle alerts. The cluster passes information about the event
to the agent via environment variables. Agents can do anything
desired with this information (send an e-mail, log to a file,
update a monitoring system, etc.).
.Simple alert configuration
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="my-alert" path="/path/to/my-script.sh" />
</alerts>
</configuration>
-----
=====
In the example above, the cluster will call +my-script.sh+ for each event.
Multiple alert agents may be configured; the cluster will call all of them for
each event.
Alert agents will be called only on cluster nodes. They will be called for
events involving Pacemaker Remote nodes, but they will never be called _on_
those nodes.
== Alert Recipients ==
Usually alerts are directed towards a recipient. Thus each alert may be additionally configured with one or more recipients.
The cluster will call the agent separately for each recipient.
.Alert configuration with recipient
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="my-alert" path="/path/to/my-script.sh">
<recipient id="my-alert-recipient" value="some-address"/>
</alert>
</alerts>
</configuration>
-----
=====
In the above example, the cluster will call +my-script.sh+ for each event,
passing the recipient +some-address+ as an environment variable.
The recipient may be anything the alert agent can recognize --
an IP address, an e-mail address, a file name, whatever the particular
agent supports.
== Alert Meta-Attributes ==
As with resource agents, meta-attributes can be configured for alert agents
to affect how Pacemaker calls them.
.Meta-Attributes of an Alert
-[width="95%",cols="m,1,2<a",options="header",align="center"]
+[width="95%",cols="m,1,<2",options="header",align="center"]
|=========================================================
|Meta-Attribute
|Default
|Description
|timestamp-format
|%H:%M:%S.%06N
|Format the cluster will use when sending the event's timestamp to the agent.
This is a string as used with the `date(1)` command.
indexterm:[Alert,Option,timestamp-format]
|timeout
|30s
|If the alert agent does not complete within this amount of time, it will be
terminated.
indexterm:[Alert,Option,timeout]
|=========================================================
Meta-attributes can be configured per alert agent and/or per recipient.
.Alert configuration with meta-attributes
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="my-alert" path="/path/to/my-script.sh">
<meta_attributes id="my-alert-attributes">
<nvpair id="my-alert-attributes-timeout" name="timeout"
value="15s"/>
</meta_attributes>
<recipient id="my-alert-recipient1" value="someuser@example.com">
<meta_attributes id="my-alert-recipient1-attributes">
<nvpair id="my-alert-recipient1-timestamp-format"
name="timestamp-format" value="%D %H:%M"/>
</meta_attributes>
</recipient>
<recipient id="my-alert-recipient2" value="otheruser@example.com">
<meta_attributes id="my-alert-recipient2-attributes">
<nvpair id="my-alert-recipient2-timestamp-format"
name="timestamp-format" value="%c"/>
</meta_attributes>
</recipient>
</alert>
</alerts>
</configuration>
-----
=====
In the above example, the +my-script.sh+ will get called twice for each event,
with each call using a 15-second timeout. One call will be passed the recipient
+someuser@example.com+ and a timestamp in the format +%D %H:%M+, while the
other call will be passed the recipient +otheruser@example.com+ and a timestamp
in the format +%c+.
== Alert Instance Attributes ==
As with resource agents, agent-specific configuration values may be configured
as instance attributes. These will be passed to the agent as additional
environment variables. The number, names and allowed values of these
instance attributes are completely up to the particular agent.
.Alert configuration with instance attributes
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="my-alert" path="/path/to/my-script.sh">
<meta_attributes id="my-alert-attributes">
<nvpair id="my-alert-attributes-timeout" name="timeout"
value="15s"/>
</meta_attributes>
<instance_attributes id="my-alert-options">
<nvpair id="my-alert-options-debug" name="debug" value="false"/>
</instance_attributes>
<recipient id="my-alert-recipient1" value="someuser@example.com"/>
</alert>
</alerts>
</configuration>
-----
=====
== Alert Filters ==
By default, an alert agent will be called for node events, fencing events, and
resource events. An agent may choose to ignore certain types of events, but
there is still the overhead of calling it for those events. To eliminate that
overhead, you may select which types of events the agent should receive.
.Alert configuration to receive only node events and fencing events
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="my-alert" path="/path/to/my-script.sh">
<select>
<select_nodes />
<select_fencing />
</select>
<recipient id="my-alert-recipient1" value="someuser@example.com"/>
</alert>
</alerts>
</configuration>
-----
=====
The possible options within +<select>+ are +<select_nodes>+,
+<select_fencing>+, +<select_resources>+, and +<select_attributes>+.
With +<select_attributes>+ (the only event type not enabled by default), the
agent will receive alerts when a node attribute changes. If you wish the agent
to be called only when certain attributes change, you can configure that as well.
.Alert configuration to be called when certain node attributes change
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="my-alert" path="/path/to/my-script.sh">
<select>
<select_attributes>
<attribute id="alert-standby" name="standby" />
<attribute id="alert-shutdown" name="shutdown" />
</select_attributes>
</select>
<recipient id="my-alert-recipient1" value="someuser@example.com"/>
</alert>
</alerts>
</configuration>
-----
=====
Node attribute alerts are currently considered experimental. Alerts may be
limited to attributes set via attrd_updater, and agents may be called multiple
times with the same attribute value.
== Using the Sample Alert Agents ==
Pacemaker provides several sample alert agents, installed in
+/usr/share/pacemaker/alerts+ by default.
While these sample scripts may be copied and used as-is, they are provided
mainly as templates to be edited to suit your purposes.
See their source code for the full set of instance attributes they support.
.Sending cluster events as SNMP traps
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="snmp_alert" path="/path/to/alert_snmp.sh">
<instance_attributes id="config_for_alert_snmp">
<nvpair id="trap_node_states" name="trap_node_states" value="all"/>
</instance_attributes>
<meta_attributes id="config_for_timestamp">
<nvpair id="ts_fmt" name="timestamp-format"
value="%Y-%m-%d,%H:%M:%S.%01N"/>
</meta_attributes>
<recipient id="snmp_destination" value="192.168.1.2"/>
</alert>
</alerts>
</configuration>
-----
=====
.Sending cluster events as e-mails
=====
[source,XML]
-----
<configuration>
<alerts>
<alert id="smtp_alert" path="/path/to/alert_smtp.sh">
<instance_attributes id="config_for_alert_smtp">
<nvpair id="email_sender" name="email_sender"
value="donotreply@example.com"/>
</instance_attributes>
<recipient id="smtp_destination" value="admin@example.com"/>
</alert>
</alerts>
</configuration>
-----
=====
== Writing an Alert Agent ==
.Environment variables passed to alert agents
-[width="95%",cols="m,2<a",options="header",align="center"]
+[width="95%",cols="m,<2",options="header",align="center"]
|=========================================================
|Environment Variable
|Description
|CRM_alert_kind
|The type of alert (+node+, +fencing+, +resource+, or +attribute+)
indexterm:[Environment Variable,CRM_alert_,kind]
|CRM_alert_version
|The version of Pacemaker sending the alert
indexterm:[Environment Variable,CRM_alert_,version]
|CRM_alert_recipient
|The configured recipient
indexterm:[Environment Variable,CRM_alert_,recipient]
|CRM_alert_node_sequence
|A sequence number increased whenever an alert is being issued on the
local node, which can be used to reference the order in which alerts have been
issued by Pacemaker. An alert for an event that happened later in time
reliably has a higher sequence number than alerts for earlier events.
Be aware that this number has no cluster-wide meaning.
indexterm:[Environment Variable,CRM_alert_node_,sequence]
|CRM_alert_timestamp
|A timestamp created prior to executing the agent, in the format
specified by the +timestamp-format+ meta-attribute. This allows the agent
to have a reliable, high-precision time of when the event occurred,
regardless of when the agent itself was invoked (which could potentially
be delayed due to system load, etc.).
indexterm:[Environment Variable,CRM_alert_,timestamp]
|CRM_alert_timestamp_epoch
|The same time as +CRM_alert_timestamp+, expressed as the integer number of
seconds since January 1, 1970. This (along with +CRM_alert_timestamp_usec+)
can be useful for alert agents that need to format time in a specific way
rather than let the user configure it.
indexterm:[Environment Variable,CRM_alert_,timestamp_epoch]
|CRM_alert_timestamp_usec
|The same time as +CRM_alert_timestamp+, expressed as the integer number of
microseconds since +CRM_alert_timestamp_epoch+.
indexterm:[Environment Variable,CRM_alert_,timestamp_usec]
|CRM_alert_node
|Name of affected node
indexterm:[Environment Variable,CRM_alert_,node]
|CRM_alert_desc
|Detail about event. For +node+ alerts, this is the node's current state
(+member+ or +lost+). For +fencing+ alerts, this is a summary of the
requested fencing operation, including origin, target, and fencing operation
error code, if any. For +resource+ alerts, this is a readable string
equivalent of +CRM_alert_status+.
indexterm:[Environment Variable,CRM_alert_,desc]
|CRM_alert_nodeid
|ID of node whose status changed (provided with +node+ alerts only)
indexterm:[Environment Variable,CRM_alert_,nodeid]
|CRM_alert_task
|The requested fencing or resource operation
(provided with +fencing+ and +resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,task]
|CRM_alert_rc
|The numerical return code of the fencing or resource operation
(provided with +fencing+ and +resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,rc]
|CRM_alert_rsc
|The name of the affected resource (+resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,rsc]
|CRM_alert_interval
|The interval of the resource operation (+resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,interval]
|CRM_alert_target_rc
|The expected numerical return code of the operation (+resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,target_rc]
|CRM_alert_status
|A numerical code used by Pacemaker to represent the operation result
(+resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,status]
|CRM_alert_exec_time
|The (wall-clock) time, in milliseconds, that it took to execute the action. If
the action timed out, +CRM_alert_status+ will be 2, +CRM_alert_desc+ will be
"Timed Out", and this value will be the action timeout. May not be supported
on all platforms. (+resource+ alerts only)
indexterm:[Environment Variable,CRM_alert_,exec_time]
|CRM_alert_attribute_name
|The name of the node attribute that changed (+attribute+ alerts only)
indexterm:[Environment Variable,CRM_alert_,attribute_name]
|CRM_alert_attribute_value
|The new value of the node attribute that changed (+attribute+ alerts only)
indexterm:[Environment Variable,CRM_alert_,attribute_value]
|=========================================================
Special concerns when writing alert agents:
* Alert agents may be called with no recipient (if none is configured),
so the agent must be able to handle this situation, even if it
only exits in that case. (Users may modify the configuration in
stages, and add a recipient later.)
* If more than one recipient is configured for an alert, the alert agent will
be called once per recipient. If an agent is not able to run concurrently, it
should be configured with only a single recipient. The agent is free,
however, to interpret the recipient as a list.
* When a cluster event occurs, all alerts are fired off at the same time as
separate processes. Depending on how many alerts and recipients are
configured, and on what is done within the alert agents,
a significant load burst may occur. The agent could be written to take
this into consideration, for example by queueing resource-intensive actions
into some other instance, instead of directly executing them.
* Alert agents are run as the +hacluster+ user, which has a minimal set
of permissions. If an agent requires additional privileges, it is
recommended to configure +sudo+ to allow the agent to run the necessary
commands as another user with the appropriate privileges.
* As always, take care to validate and sanitize user-configured parameters,
such as CRM_alert_timestamp (whose content is specified by the
user-configured timestamp-format), CRM_alert_recipient, and all instance
attributes. Mostly this is needed simply to protect against configuration
errors, but if some user can modify the CIB without having hacluster-level
access to the cluster nodes, it is a potential security concern as well, to
avoid the possibility of code injection.
[NOTE]
=====
The alerts interface is designed to be backward compatible with the external
scripts interface used by the +ocf:pacemaker:ClusterMon+ resource, which is
now deprecated. To preserve this compatibility, the environment variables
passed to alert agents are available prepended with +CRM_notify_+
as well as +CRM_alert_+. One break in compatibility is that ClusterMon ran
external scripts as the +root+ user, while alert agents are run as the
+hacluster+ user.
=====
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt b/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt
index 694c35d053..49864c9dfd 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt
@@ -1,881 +1,881 @@
= Resource Constraints =
indexterm:[Resource,Constraints]
== Scores ==
Scores of all kinds are integral to how the cluster works.
Practically everything from moving a resource to deciding which
resource to stop in a degraded cluster is achieved by manipulating
scores in some way.
Scores are calculated per resource and node. Any node with a
negative score for a resource can't run that resource. The cluster
places a resource on the node with the highest score for it.
=== Infinity Math ===
Pacemaker implements +INFINITY+ (or equivalently, ++INFINITY+) internally as a
score of 1,000,000. Addition and subtraction with it follow these three basic
rules:
* Any value + +INFINITY+ = +INFINITY+
* Any value - +INFINITY+ = +-INFINITY+
* +INFINITY+ - +INFINITY+ = +-INFINITY+
[NOTE]
======
What if you want to use a score higher than 1,000,000? Typically this possibility
arises when someone wants to base the score on some external metric that might
go above 1,000,000.
The short answer is you can't.
The long answer is it is sometimes possible work around this limitation
creatively. You may be able to set the score to some computed value based on
the external metric rather than use the metric directly. For nodes, you can
store the metric as a node attribute, and query the attribute when computing
the score (possibly as part of a custom resource agent).
======
== Deciding Which Nodes a Resource Can Run On ==
indexterm:[Location Constraints]
indexterm:[Resource,Constraints,Location]
'Location constraints' tell the cluster which nodes a resource can run on.
There are two alternative strategies. One way is to say that, by default,
resources can run anywhere, and then the location constraints specify nodes
that are not allowed (an 'opt-out' cluster). The other way is to start with
nothing able to run anywhere, and use location constraints to selectively
enable allowed nodes (an 'opt-in' cluster).
Whether you should choose opt-in or opt-out depends on your
personal preference and the make-up of your cluster. If most of your
resources can run on most of the nodes, then an opt-out arrangement is
likely to result in a simpler configuration. On the other-hand, if
most resources can only run on a small subset of nodes, an opt-in
configuration might be simpler.
=== Location Properties ===
.Properties of a rsc_location Constraint
-[width="95%",cols="2m,1,5<a",options="header",align="center"]
+[width="95%",cols="2m,1,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the constraint
indexterm:[id,Location Constraints]
indexterm:[Constraints,Location,id]
|rsc
|
|The name of the resource to which this constraint applies
indexterm:[rsc,Location Constraints]
indexterm:[Constraints,Location,rsc]
|rsc-pattern
|
|An extended regular expression (as defined in
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04[POSIX])
matching the names of resources to which this constraint
applies, if +rsc+ is not specified; if the regular expression contains
submatches and the constraint is governed by a rule (see <<ch-rules>>), the
submatches can be referenced as +%0+ through +%9+ in the rule's
+score-attribute+ or a rule expression's +attribute+
indexterm:[rsc-pattern,Location Constraints]
indexterm:[Constraints,Location,rsc-pattern]
|node
|
|A node's name
indexterm:[node,Location Constraints]
indexterm:[Constraints,Location,node]
|score
|
|Positive values indicate a preference for running the affected resource(s) on
this node -- the higher the value, the stronger the preference. Negative values
indicate the resource(s) should avoid this node (a value of +-INFINITY+
changes "should" to "must").
indexterm:[score,Location Constraints]
indexterm:[Constraints,Location,score]
|resource-discovery
|always
-|Whether Pacemaker should perform resource discovery (that is, check whether
+a|Whether Pacemaker should perform resource discovery (that is, check whether
the resource is already running) for this resource on this node. This should
normally be left as the default, so that rogue instances of a service can be
stopped when they are running where they are not supposed to be. However,
there are two situations where disabling resource discovery is a good idea:
when a service is not installed on a node, discovery might return an error
(properly written OCF agents will not, so this is usually only seen with other
agent types); and when Pacemaker Remote is used to scale a cluster to hundreds
of nodes, limiting resource discovery to allowed nodes can significantly boost
performance.
* +always:+ Always perform resource discovery for the specified resource on this node.
* +never:+ Never perform resource discovery for the specified resource on this node.
This option should generally be used with a -INFINITY score, although that is not strictly
required.
* +exclusive:+ Perform resource discovery for the specified resource only on
this node (and other nodes similarly marked as +exclusive+). Multiple location
constraints using +exclusive+ discovery for the same resource across
different nodes creates a subset of nodes resource-discovery is exclusive to.
If a resource is marked for +exclusive+ discovery on one or more nodes, that
resource is only allowed to be placed within that subset of nodes.
indexterm:[Resource Discovery,Location Constraints]
indexterm:[Constraints,Location,Resource Discovery]
|=========================================================
[WARNING]
=========
Setting resource-discovery to +never+ or +exclusive+ removes Pacemaker's
ability to detect and stop unwanted instances of a service running
where it's not supposed to be. It is up to the system administrator (you!)
to make sure that the service can 'never' be active on nodes without
resource-discovery (such as by leaving the relevant software uninstalled).
=========
=== Asymmetrical "Opt-In" Clusters ===
indexterm:[Asymmetrical Opt-In Clusters]
indexterm:[Cluster Type,Asymmetrical Opt-In]
To create an opt-in cluster, start by preventing resources from
running anywhere by default:
----
# crm_attribute --name symmetric-cluster --update false
----
Then start enabling nodes. The following fragment says that the web
server prefers *sles-1*, the database prefers *sles-2* and both can
fail over to *sles-3* if their most preferred node fails.
.Opt-in location constraints for two resources
======
[source,XML]
-------
<constraints>
<rsc_location id="loc-1" rsc="Webserver" node="sles-1" score="200"/>
<rsc_location id="loc-2" rsc="Webserver" node="sles-3" score="0"/>
<rsc_location id="loc-3" rsc="Database" node="sles-2" score="200"/>
<rsc_location id="loc-4" rsc="Database" node="sles-3" score="0"/>
</constraints>
-------
======
=== Symmetrical "Opt-Out" Clusters ===
indexterm:[Symmetrical Opt-Out Clusters]
indexterm:[Cluster Type,Symmetrical Opt-Out]
To create an opt-out cluster, start by allowing resources to run
anywhere by default:
----
# crm_attribute --name symmetric-cluster --update true
----
Then start disabling nodes. The following fragment is the equivalent
of the above opt-in configuration.
.Opt-out location constraints for two resources
======
[source,XML]
-------
<constraints>
<rsc_location id="loc-1" rsc="Webserver" node="sles-1" score="200"/>
<rsc_location id="loc-2-dont-run" rsc="Webserver" node="sles-2" score="-INFINITY"/>
<rsc_location id="loc-3-dont-run" rsc="Database" node="sles-1" score="-INFINITY"/>
<rsc_location id="loc-4" rsc="Database" node="sles-2" score="200"/>
</constraints>
-------
======
[[node-score-equal]]
=== What if Two Nodes Have the Same Score ===
If two nodes have the same score, then the cluster will choose one.
This choice may seem random and may not be what was intended, however
the cluster was not given enough information to know any better.
.Constraints where a resource prefers two nodes equally
======
[source,XML]
-------
<constraints>
<rsc_location id="loc-1" rsc="Webserver" node="sles-1" score="INFINITY"/>
<rsc_location id="loc-2" rsc="Webserver" node="sles-2" score="INFINITY"/>
<rsc_location id="loc-3" rsc="Database" node="sles-1" score="500"/>
<rsc_location id="loc-4" rsc="Database" node="sles-2" score="300"/>
<rsc_location id="loc-5" rsc="Database" node="sles-2" score="200"/>
</constraints>
-------
======
In the example above, assuming no other constraints and an inactive
cluster, +Webserver+ would probably be placed on +sles-1+ and +Database+ on
+sles-2+. It would likely have placed +Webserver+ based on the node's
uname and +Database+ based on the desire to spread the resource load
evenly across the cluster. However other factors can also be involved
in more complex configurations.
[[s-resource-ordering]]
== Specifying the Order in which Resources Should Start/Stop ==
indexterm:[Resource,Constraints,Ordering]
indexterm:[Resource,Start Order]
indexterm:[Ordering Constraints]
'Ordering constraints' tell the cluster the order in which resources should
start.
[IMPORTANT]
====
Ordering constraints affect 'only' the ordering of resources;
they do 'not' require that the resources be placed on the
same node. If you want resources to be started on the same node
'and' in a specific order, you need both an ordering constraint 'and'
a colocation constraint (see <<s-resource-colocation>>), or
alternatively, a group (see <<group-resources>>).
====
=== Ordering Properties ===
.Properties of a rsc_order Constraint
-[width="95%",cols="1m,1,4<a",options="header",align="center"]
+[width="95%",cols="1m,1,<4",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the constraint
indexterm:[id,Ordering Constraints]
indexterm:[Constraints,Ordering,id]
|first
|
|Name of the resource that the +then+ resource depends on
indexterm:[first,Ordering Constraints]
indexterm:[Constraints,Ordering,first]
|then
|
|Name of the dependent resource
indexterm:[then,Ordering Constraints]
indexterm:[Constraints,Ordering,then]
|first-action
|start
|The action that the +first+ resource must complete before +then-action+
can be initiated for the +then+ resource. Allowed values: +start+,
+stop+, +promote+, +demote+.
indexterm:[first-action,Ordering Constraints]
indexterm:[Constraints,Ordering,first-action]
|then-action
|value of +first-action+
|The action that the +then+ resource can execute only after the
+first-action+ on the +first+ resource has completed. Allowed
values: +start+, +stop+, +promote+, +demote+.
indexterm:[then-action,Ordering Constraints]
indexterm:[Constraints,Ordering,then-action]
|kind
|
-|How to enforce the constraint. Allowed values:
+a|How to enforce the constraint. Allowed values:
* +Optional:+ Just a suggestion. Only applies if both resources are
executing the specified actions. Any change in state by the +first+ resource
will have no effect on the +then+ resource.
* +Mandatory:+ Always. If +first+ does not perform +first-action+, +then+ will
not be allowed to performed +then-action+. If +first+ is restarted, +then+
(if running) will be stopped beforehand and started afterward.
* +Serialize:+ Ensure that no two stop/start actions occur concurrently
for the resources. +First+ and +then+ can start in either order,
but one must complete starting before the other can be started. A typical use
case is when resource start-up puts a high load on the host.
indexterm:[kind,Ordering Constraints]
indexterm:[Constraints,Ordering,kind]
|symmetrical
|TRUE for +Mandatory+ and +Optional+ kinds. FALSE for +Serialize+ kind.
|If true, the reverse of the constraint applies for the opposite action (for
example, if B starts after A starts, then B stops before A stops).
+Serialize+ orders cannot be symmetrical.
indexterm:[symmetrical,Ordering Constraints]
indexterm:[Ordering Constraints,symmetrical]
|=========================================================
+Promote+ and +demote+ apply to the master role of
<<s-resource-promotable,promotable>> resources.
=== Optional and mandatory ordering ===
Here is an example of ordering constraints where +Database+ 'must' start before
+Webserver+, and +IP+ 'should' start before +Webserver+ if they both need to be
started:
.Optional and mandatory ordering constraints
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1" first="IP" then="Webserver" kind="Optional"/>
<rsc_order id="order-2" first="Database" then="Webserver" kind="Mandatory" />
</constraints>
-------
======
Because the above example lets +symmetrical+ default to TRUE,
+Webserver+ must be stopped before +Database+ can be stopped,
and +Webserver+ should be stopped before +IP+
if they both need to be stopped.
[[s-resource-colocation]]
== Placing Resources Relative to other Resources ==
indexterm:[Resource,Constraints,Colocation]
indexterm:[Resource,Location Relative to other Resources]
'Colocation constraints' tell the cluster that the location of one resource
depends on the location of another one.
Colocation has an important side-effect: it affects the order in which
resources are assigned to a node. Think about it: You can't place A relative to
B unless you know where B is.
footnote:[
While the human brain is sophisticated enough to read the constraint
in any order and choose the correct one depending on the situation,
the cluster is not quite so smart. Yet.
]
So when you are creating colocation constraints, it is important to
consider whether you should colocate A with B, or B with A.
Another thing to keep in mind is that, assuming A is colocated with
B, the cluster will take into account A's preferences when
deciding which node to choose for B.
For a detailed look at exactly how this occurs, see
http://clusterlabs.org/doc/Colocation_Explained.pdf[Colocation Explained].
[IMPORTANT]
====
Colocation constraints affect 'only' the placement of resources; they do 'not'
require that the resources be started in a particular order. If you want
resources to be started on the same node 'and' in a specific order, you need
both an ordering constraint (see <<s-resource-ordering>>) 'and' a colocation
constraint, or alternatively, a group (see <<group-resources>>).
====
=== Colocation Properties ===
.Properties of a rsc_colocation Constraint
-[width="95%",cols="1m,1,4<",options="header",align="center"]
+[width="95%",cols="1m,1,<4",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the constraint (required).
indexterm:[id,Colocation Constraints]
indexterm:[Constraints,Colocation,id]
|rsc
|
|The name of a resource that should be located relative to +with-rsc+ (required).
indexterm:[rsc,Colocation Constraints]
indexterm:[Constraints,Colocation,rsc]
|with-rsc
|
|The name of the resource used as the colocation target. The cluster will
decide where to put this resource first and then decide where to put +rsc+ (required).
indexterm:[with-rsc,Colocation Constraints]
indexterm:[Constraints,Colocation,with-rsc]
|node-attribute
|#uname
|The node attribute that must be the same on the node running +rsc+ and the
node running +with-rsc+ for the constraint to be satisfied. (For details,
see <<s-coloc-attribute>>.)
indexterm:[node-attribute,Colocation Constraints]
indexterm:[Constraints,Colocation,node-attribute]
|score
|
|Positive values indicate the resources should run on the same
node. Negative values indicate the resources should run on
different nodes. Values of \+/- +INFINITY+ change "should" to "must".
indexterm:[score,Colocation Constraints]
indexterm:[Constraints,Colocation,score]
|=========================================================
=== Mandatory Placement ===
Mandatory placement occurs when the constraint's score is
++INFINITY+ or +-INFINITY+. In such cases, if the constraint can't be
satisfied, then the +rsc+ resource is not permitted to run. For
+score=INFINITY+, this includes cases where the +with-rsc+ resource is
not active.
If you need resource +A+ to always run on the same machine as
resource +B+, you would add the following constraint:
.Mandatory colocation constraint for two resources
====
[source,XML]
<rsc_colocation id="colocate" rsc="A" with-rsc="B" score="INFINITY"/>
====
Remember, because +INFINITY+ was used, if +B+ can't run on any
of the cluster nodes (for whatever reason) then +A+ will not
be allowed to run. Whether +A+ is running or not has no effect on +B+.
Alternatively, you may want the opposite -- that +A+ 'cannot'
run on the same machine as +B+. In this case, use
+score="-INFINITY"+.
.Mandatory anti-colocation constraint for two resources
====
[source,XML]
<rsc_colocation id="anti-colocate" rsc="A" with-rsc="B" score="-INFINITY"/>
====
Again, by specifying +-INFINITY+, the constraint is binding. So if the
only place left to run is where +B+ already is, then
+A+ may not run anywhere.
As with +INFINITY+, +B+ can run even if +A+ is stopped.
However, in this case +A+ also can run if +B+ is stopped, because it still
meets the constraint of +A+ and +B+ not running on the same node.
=== Advisory Placement ===
If mandatory placement is about "must" and "must not", then advisory
placement is the "I'd prefer if" alternative. For constraints with
scores greater than +-INFINITY+ and less than +INFINITY+, the cluster
will try to accommodate your wishes but may ignore them if the
alternative is to stop some of the cluster resources.
As in life, where if enough people prefer something it effectively
becomes mandatory, advisory colocation constraints can combine with
other elements of the configuration to behave as if they were
mandatory.
.Advisory colocation constraint for two resources
====
[source,XML]
<rsc_colocation id="colocate-maybe" rsc="A" with-rsc="B" score="500"/>
====
[[s-coloc-attribute]]
=== Colocation by Node Attribute ===
The +node-attribute+ property of a colocation constraints allows you to express
the requirement, "these resources must be on similar nodes".
As an example, imagine that you have two Storage Area Networks (SANs) that are
not controlled by the cluster, and each node is connected to one or the other.
You may have two resources +r1+ and +r2+ such that +r2+ needs to use the same
SAN as +r1+, but doesn't necessarily have to be on the same exact node.
In such a case, you could define a <<s-node-attributes,node attribute>> named
+san+, with the value +san1+ or +san2+ on each node as appropriate. Then, you
could colocate +r2+ with +r1+ using +node-attribute+ set to +san+.
[[s-resource-sets]]
== Resource Sets ==
'Resource sets' allow multiple resources to be affected by a single constraint.
.A set of 3 resources
====
[source,XML]
----
<resource_set id="resource-set-example">
<resource_ref id="A"/>
<resource_ref id="B"/>
<resource_ref id="C"/>
</resource_set>
----
====
Resource sets are valid inside +rsc_location+,
+rsc_order+ (see <<s-resource-sets-ordering>>),
+rsc_colocation+ (see <<s-resource-sets-colocation>>),
and +rsc_ticket+ (see <<s-ticket-constraints>>) constraints.
A resource set has a number of properties that can be set,
though not all have an effect in all contexts.
.Properties of a resource_set
-[width="95%",cols="2m,1,5<a",options="header",align="center"]
+[width="95%",cols="2m,1,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the set
indexterm:[id,Resource Sets]
indexterm:[Constraints,Resource Sets,id]
|sequential
|true
|Whether the members of the set must be acted on in order.
Meaningful within +rsc_order+ and +rsc_colocation+.
indexterm:[sequential,Resource Sets]
indexterm:[Constraints,Resource Sets,sequential]
|require-all
|true
|Whether all members of the set must be active before continuing.
With the current implementation, the cluster may continue even if only one
member of the set is started, but if more than one member of the set is
starting at the same time, the cluster will still wait until all of those have
started before continuing (this may change in future versions).
Meaningful within +rsc_order+.
indexterm:[require-all,Resource Sets]
indexterm:[Constraints,Resource Sets,require-all]
|role
|
|Limit the effect of the constraint to the specified role.
Meaningful within +rsc_location+, +rsc_colocation+ and +rsc_ticket+.
indexterm:[role,Resource Sets]
indexterm:[Constraints,Resource Sets,role]
|action
|
|Limit the effect of the constraint to the specified action.
Meaningful within +rsc_order+.
indexterm:[action,Resource Sets]
indexterm:[Constraints,Resource Sets,action]
|score
|
|'Advanced use only.' Use a specific score for this set within the constraint.
indexterm:[score,Resource Sets]
indexterm:[Constraints,Resource Sets,score]
|=========================================================
[[s-resource-sets-ordering]]
== Ordering Sets of Resources ==
A common situation is for an administrator to create a chain of
ordered resources, such as:
.A chain of ordered resources
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1" first="A" then="B" />
<rsc_order id="order-2" first="B" then="C" />
<rsc_order id="order-3" first="C" then="D" />
</constraints>
-------
======
.Visual representation of the four resources' start order for the above constraints
image::images/resource-set.png["Ordered set",width="16cm",height="2.5cm",align="center"]
=== Ordered Set ===
To simplify this situation, resource sets (see <<s-resource-sets>>) can be used
within ordering constraints:
.A chain of ordered resources expressed as a set
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1">
<resource_set id="ordered-set-example" sequential="true">
<resource_ref id="A"/>
<resource_ref id="B"/>
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
</rsc_order>
</constraints>
-------
======
While the set-based format is not less verbose, it is significantly
easier to get right and maintain.
[IMPORTANT]
=========
If you use a higher-level tool, pay attention to how it exposes this
functionality. Depending on the tool, creating a set +A B+ may be equivalent to
+A then B+, or +B then A+.
=========
=== Ordering Multiple Sets ===
The syntax can be expanded to allow sets of resources to be ordered relative to
each other, where the members of each individual set may be ordered or
unordered (controlled by the +sequential+ property). In the example below, +A+
and +B+ can both start in parallel, as can +C+ and +D+, however +C+ and +D+ can
only start once _both_ +A+ _and_ +B+ are active.
.Ordered sets of unordered resources
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1">
<resource_set id="ordered-set-1" sequential="false">
<resource_ref id="A"/>
<resource_ref id="B"/>
</resource_set>
<resource_set id="ordered-set-2" sequential="false">
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
</rsc_order>
</constraints>
-------
======
.Visual representation of the start order for two ordered sets of unordered resources
image::images/two-sets.png["Two ordered sets",width="13cm",height="7.5cm",align="center"]
Of course either set -- or both sets -- of resources can also be
internally ordered (by setting +sequential="true"+) and there is no
limit to the number of sets that can be specified.
.Advanced use of set ordering - Three ordered sets, two of which are internally unordered
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1">
<resource_set id="ordered-set-1" sequential="false">
<resource_ref id="A"/>
<resource_ref id="B"/>
</resource_set>
<resource_set id="ordered-set-2" sequential="true">
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
<resource_set id="ordered-set-3" sequential="false">
<resource_ref id="E"/>
<resource_ref id="F"/>
</resource_set>
</rsc_order>
</constraints>
-------
======
.Visual representation of the start order for the three sets defined above
image::images/three-sets.png["Three ordered sets",width="16cm",height="7.5cm",align="center"]
[IMPORTANT]
====
An ordered set with +sequential=false+ makes sense only if there is another
set in the constraint. Otherwise, the constraint has no effect.
====
=== Resource Set OR Logic ===
The unordered set logic discussed so far has all been "AND" logic.
To illustrate this take the 3 resource set figure in the previous section.
Those sets can be expressed, +(A and B) then \(C) then (D) then (E and F)+.
Say for example we want to change the first set, +(A and B)+, to use "OR" logic
so the sets look like this: +(A or B) then \(C) then (D) then (E and F)+.
This functionality can be achieved through the use of the +require-all+
option. This option defaults to TRUE which is why the
"AND" logic is used by default. Setting +require-all=false+ means only one
resource in the set needs to be started before continuing on to the next set.
.Resource Set "OR" logic: Three ordered sets, where the first set is internally unordered with "OR" logic
======
[source,XML]
-------
<constraints>
<rsc_order id="order-1">
<resource_set id="ordered-set-1" sequential="false" require-all="false">
<resource_ref id="A"/>
<resource_ref id="B"/>
</resource_set>
<resource_set id="ordered-set-2" sequential="true">
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
<resource_set id="ordered-set-3" sequential="false">
<resource_ref id="E"/>
<resource_ref id="F"/>
</resource_set>
</rsc_order>
</constraints>
-------
======
[IMPORTANT]
====
An ordered set with +require-all=false+ makes sense only in conjunction with
+sequential=false+. Think of it like this: +sequential=false+ modifies the set
to be an unordered set using "AND" logic by default, and adding
+require-all=false+ flips the unordered set's "AND" logic to "OR" logic.
====
[[s-resource-sets-colocation]]
== Colocating Sets of Resources ==
Another common situation is for an administrator to create a set of
colocated resources.
One way to do this would be to define a resource group (see
<<group-resources>>), but that cannot always accurately express the desired
state.
Another way would be to define each relationship as an individual constraint,
but that causes a constraint explosion as the number of resources and
combinations grow. An example of this approach:
.Chain of colocated resources
======
[source,XML]
-------
<constraints>
<rsc_colocation id="coloc-1" rsc="D" with-rsc="C" score="INFINITY"/>
<rsc_colocation id="coloc-2" rsc="C" with-rsc="B" score="INFINITY"/>
<rsc_colocation id="coloc-3" rsc="B" with-rsc="A" score="INFINITY"/>
</constraints>
-------
======
To make things easier, resource sets (see <<s-resource-sets>>) can be used
within colocation constraints. As with the chained version, a
resource that can't be active prevents any resource that must be
colocated with it from being active. For example, if +B+ is not
able to run, then both +C+ and by inference +D+ must also remain
stopped. Here is an example +resource_set+:
.Equivalent colocation chain expressed using +resource_set+
======
[source,XML]
-------
<constraints>
<rsc_colocation id="coloc-1" score="INFINITY" >
<resource_set id="colocated-set-example" sequential="true">
<resource_ref id="A"/>
<resource_ref id="B"/>
<resource_ref id="C"/>
<resource_ref id="D"/>
</resource_set>
</rsc_colocation>
</constraints>
-------
======
[IMPORTANT]
=========
If you use a higher-level tool, pay attention to how it exposes this
functionality. Depending on the tool, creating a set +A B+ may be equivalent to
+A with B+, or +B with A+.
=========
This notation can also be used to tell the cluster that sets of resources must
be colocated relative to each other, where the individual members of each set
may or may not depend on each other being active (controlled by the
+sequential+ property).
In this example, +A+, +B+, and +C+ will each be colocated with +D+.
+D+ must be active, but any of +A+, +B+, or +C+ may be inactive without
affecting any other resources.
.Using colocated sets to specify a common peer
======
[source,XML]
-------
<constraints>
<rsc_colocation id="coloc-1" score="INFINITY" >
<resource_set id="colocated-set-1" sequential="false">
<resource_ref id="A"/>
<resource_ref id="B"/>
<resource_ref id="C"/>
</resource_set>
<resource_set id="colocated-set-2" sequential="true">
<resource_ref id="D"/>
</resource_set>
</rsc_colocation>
</constraints>
-------
======
[IMPORTANT]
====
A colocated set with +sequential=false+ makes sense only if there is another
set in the constraint. Otherwise, the constraint has no effect.
====
There is no inherent limit to the number and size of the sets used.
The only thing that matters is that in order for any member of one set
in the constraint to be active, all members of sets listed after it must also
be active (and naturally on the same node); and if a set has +sequential="true"+,
then in order for one member of that set to be active, all members listed
before it must also be active.
If desired, you can restrict the dependency to instances of promotable clone
resources that are in a specific role, using the set's +role+ property.
.Colocation chain in which the members of the middle set have no interdependencies, and the last listed set (which the cluster places first) is restricted to instances in master status.
======
[source,XML]
-------
<constraints>
<rsc_colocation id="coloc-1" score="INFINITY" >
<resource_set id="colocated-set-1" sequential="true">
<resource_ref id="B"/>
<resource_ref id="A"/>
</resource_set>
<resource_set id="colocated-set-2" sequential="false">
<resource_ref id="C"/>
<resource_ref id="D"/>
<resource_ref id="E"/>
</resource_set>
<resource_set id="colocated-set-3" sequential="true" role="Master">
<resource_ref id="G"/>
<resource_ref id="F"/>
</resource_set>
</rsc_colocation>
</constraints>
-------
======
.Visual representation the above example (resources to the left are placed first)
image::images/three-sets-complex.png["Colocation chain",width="16cm",height="9cm",align="center"]
[NOTE]
====
Pay close attention to the order in which resources and sets are listed.
While the colocation dependency for members of any one set is last-to-first,
the colocation dependency for multiple sets is first-to-last. In the above
example, +B+ is colocated with +A+, but +colocated-set-1+ is
colocated with +colocated-set-2+.
Unlike ordered sets, colocated sets do not use the +require-all+ option.
====
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Options.txt b/doc/Pacemaker_Explained/en-US/Ch-Options.txt
index e2431181b0..b9cc00912c 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Options.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Options.txt
@@ -1,409 +1,410 @@
= Cluster-Wide Configuration =
== Configuration Layout ==
The cluster is defined by the Cluster Information Base (CIB),
which uses XML notation. The simplest CIB, an empty one, looks like this:
.An empty configuration
======
[source,XML]
-------
<cib crm_feature_set="3.0.7" validate-with="pacemaker-1.2" admin_epoch="1" epoch="0" num_updates="0">
<configuration>
<crm_config/>
<nodes/>
<resources/>
<constraints/>
</configuration>
<status/>
</cib>
-------
======
The empty configuration above contains the major sections that make up a CIB:
* +cib+: The entire CIB is enclosed with a +cib+ tag. Certain fundamental settings
are defined as attributes of this tag.
** +configuration+: This section -- the primary focus of this document --
contains traditional configuration information such as what resources the
cluster serves and the relationships among them.
*** +crm_config+: cluster-wide configuration options
*** +nodes+: the machines that host the cluster
*** +resources+: the services run by the cluster
*** +constraints+: indications of how resources should be placed
** +status+: This section contains the history of each resource on each node.
Based on this data, the cluster can construct the complete current
state of the cluster. The authoritative source for this section
is the local executor (pacemaker-execd process) on each cluster node, and
the cluster will occasionally repopulate the entire section. For this
reason, it is never written to disk, and administrators are advised
against modifying it in any way.
In this document, configuration settings will be described as 'properties' or 'options'
based on how they are defined in the CIB:
* Properties are XML attributes of an XML element.
* Options are name-value pairs expressed as +nvpair+ child elements of an XML element.
Normally, you will use command-line tools that abstract the XML, so the
distinction will be unimportant; both properties and options are
cluster settings you can tweak.
== CIB Properties ==
Certain settings are defined by CIB properties (that is, attributes of the
+cib+ tag) rather than with the rest of the cluster configuration in the
+configuration+ section.
The reason is simply a matter of parsing. These options are used by the
configuration database which is, by design, mostly ignorant of the content it
holds. So the decision was made to place them in an easy-to-find location.
.CIB Properties
-[width="95%",cols="2m,5<",options="header",align="center"]
+[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field |Description
| admin_epoch |
indexterm:[Configuration Version,Cluster]
indexterm:[Cluster,Option,Configuration Version]
indexterm:[admin_epoch,Cluster Option]
indexterm:[Cluster,Option,admin_epoch]
When a node joins the cluster, the cluster performs a check to see
which node has the best configuration. It asks the node with the highest
(+admin_epoch+, +epoch+, +num_updates+) tuple to replace the configuration on
all the nodes -- which makes setting them, and setting them correctly, very
important. +admin_epoch+ is never modified by the cluster; you can use this
to make the configurations on any inactive nodes obsolete. _Never set this
value to zero_. In such cases, the cluster cannot tell the difference between
your configuration and the "empty" one used when nothing is found on disk.
| epoch |
indexterm:[epoch,Cluster Option]
indexterm:[Cluster,Option,epoch]
The cluster increments this every time the configuration is updated (usually by
the administrator).
| num_updates |
indexterm:[num_updates,Cluster Option]
indexterm:[Cluster,Option,num_updates]
The cluster increments this every time the configuration or status is updated
(usually by the cluster) and resets it to 0 when epoch changes.
| validate-with |
indexterm:[validate-with,Cluster Option]
indexterm:[Cluster,Option,validate-with]
Determines the type of XML validation that will be done on the configuration.
If set to +none+, the cluster will not verify that updates conform to the
DTD (nor reject ones that don't). This option can be useful when
operating a mixed-version cluster during an upgrade.
|cib-last-written |
indexterm:[cib-last-written,Cluster Property]
indexterm:[Cluster,Property,cib-last-written]
Indicates when the configuration was last written to disk. Maintained by the
cluster; for informational purposes only.
|have-quorum |
indexterm:[have-quorum,Cluster Property]
indexterm:[Cluster,Property,have-quorum]
Indicates if the cluster has quorum. If false, this may mean that the
cluster cannot start resources or fence other nodes (see
+no-quorum-policy+ below). Maintained by the cluster.
|dc-uuid |
indexterm:[dc-uuid,Cluster Property]
indexterm:[Cluster,Property,dc-uuid]
Indicates which cluster node is the current leader. Used by the
cluster when placing resources and determining the order of some
events. Maintained by the cluster.
|=========================================================
[[s-cluster-options]]
== Cluster Options ==
Cluster options, as you might expect, control how the cluster behaves
when confronted with certain situations.
They are grouped into sets within the +crm_config+ section, and, in advanced
configurations, there may be more than one set. (This will be described later
in the section on <<ch-rules>> where we will show how to have the cluster use
different sets of options during working hours than during weekends.) For now,
we will describe the simple case where each option is present at most once.
You can obtain an up-to-date list of cluster options, including
their default values, by running the `man pacemaker-schedulerd` and
`man pacemaker-controld` commands.
.Cluster Options
-[width="95%",cols="5m,2,11<a",options="header",align="center"]
+[width="95%",cols="5m,2,<11",options="header",align="center"]
|=========================================================
|Option |Default |Description
| dc-version | |
indexterm:[dc-version,Cluster Property]
indexterm:[Cluster,Property,dc-version]
Version of Pacemaker on the cluster's DC.
Determined automatically by the cluster.
Often includes the hash which identifies the exact Git changeset it was built
from. Used for diagnostic purposes.
| cluster-infrastructure | |
indexterm:[cluster-infrastructure,Cluster Property]
indexterm:[Cluster,Property,cluster-infrastructure]
The messaging stack on which Pacemaker is currently running.
Determined automatically by the cluster.
Used for informational and diagnostic purposes.
-| no-quorum-policy | stop |
+| no-quorum-policy | stop
+a|
indexterm:[no-quorum-policy,Cluster Option]
indexterm:[Cluster,Option,no-quorum-policy]
What to do when the cluster does not have quorum. Allowed values:
* +ignore:+ continue all resource management
* +freeze:+ continue resource management, but don't recover resources from nodes not in the affected partition
* +stop:+ stop all resources in the affected cluster partition
* +suicide:+ fence all nodes in the affected cluster partition
| batch-limit | 0 |
indexterm:[batch-limit,Cluster Option]
indexterm:[Cluster,Option,batch-limit]
The maximum number of actions that the cluster may execute in parallel across
all nodes. The "correct" value will depend on the speed and load of your
network and cluster nodes. If zero, the cluster will impose a dynamically
calculated limit only when any node has high load.
| migration-limit | -1 |
indexterm:[migration-limit,Cluster Option]
indexterm:[Cluster,Option,migration-limit]
The number of migration jobs that the TE is allowed to execute in
parallel on a node. A value of -1 means unlimited.
| symmetric-cluster | TRUE |
indexterm:[symmetric-cluster,Cluster Option]
indexterm:[Cluster,Option,symmetric-cluster]
Can all resources run on any node by default?
| stop-all-resources | FALSE |
indexterm:[stop-all-resources,Cluster Option]
indexterm:[Cluster,Option,stop-all-resources]
Should the cluster stop all resources?
| stop-orphan-resources | TRUE |
indexterm:[stop-orphan-resources,Cluster Option]
indexterm:[Cluster,Option,stop-orphan-resources]
Should deleted resources be stopped? This value takes precedence over
+is-managed+ (i.e. even unmanaged resources will be stopped if deleted from
the configuration when this value is TRUE).
| stop-orphan-actions | TRUE |
indexterm:[stop-orphan-actions,Cluster Option]
indexterm:[Cluster,Option,stop-orphan-actions]
Should deleted actions be cancelled?
| start-failure-is-fatal | TRUE |
indexterm:[start-failure-is-fatal,Cluster Option]
indexterm:[Cluster,Option,start-failure-is-fatal]
Should a failure to start a resource on a particular node prevent further start
attempts on that node? If FALSE, the cluster will decide whether the same
node is still eligible based on the resource's current failure count
and +migration-threshold+ (see <<s-failure-handling>>).
| enable-startup-probes | TRUE |
indexterm:[enable-startup-probes,Cluster Option]
indexterm:[Cluster,Option,enable-startup-probes]
Should the cluster check for active resources during startup?
| maintenance-mode | FALSE |
indexterm:[maintenance-mode,Cluster Option]
indexterm:[Cluster,Option,maintenance-mode]
Should the cluster refrain from monitoring, starting and stopping resources?
| stonith-enabled | TRUE |
indexterm:[stonith-enabled,Cluster Option]
indexterm:[Cluster,Option,stonith-enabled]
Should failed nodes and nodes with resources that can't be stopped be
shot? If you value your data, set up a STONITH device and enable this.
If true, or unset, the cluster will refuse to start resources unless
one or more STONITH resources have been configured.
If false, unresponsive nodes are immediately assumed to be running no
resources, and resource takeover to online nodes starts without any
further protection (which means _data loss_ if the unresponsive node
still accesses shared storage, for example). See also the +requires+
meta-attribute in <<s-resource-options>>.
| stonith-action | reboot |
indexterm:[stonith-action,Cluster Option]
indexterm:[Cluster,Option,stonith-action]
Action to send to STONITH device. Allowed values are +reboot+ and +off+.
The value +poweroff+ is also allowed, but is only used for
legacy devices.
| stonith-timeout | 60s |
indexterm:[stonith-timeout,Cluster Option]
indexterm:[Cluster,Option,stonith-timeout]
How long to wait for STONITH actions (reboot, on, off) to complete
| stonith-max-attempts | 10 |
indexterm:[stonith-max-attempts,Cluster Option]
indexterm:[Cluster,Option,stonith-max-attempts]
How many times fencing can fail for a target before the cluster will no longer
immediately re-attempt it.
| stonith-watchdog-timeout | 0 |
indexterm:[stonith-watchdog-timeout,Cluster Option]
indexterm:[Cluster,Option,stonith-watchdog-timeout]
If nonzero, rely on hardware watchdog self-fencing. If positive, assume unseen
nodes self-fence within this much time. If negative, and the
SBD_WATCHDOG_TIMEOUT environment variable is set, use twice that value.
| concurrent-fencing | FALSE |
indexterm:[concurrent-fencing,Cluster Option]
indexterm:[Cluster,Option,concurrent-fencing]
Is the cluster allowed to initiate multiple fence actions concurrently?
| cluster-delay | 60s |
indexterm:[cluster-delay,Cluster Option]
indexterm:[Cluster,Option,cluster-delay]
Estimated maximum round-trip delay over the network (excluding action
execution). If the TE requires an action to be executed on another node,
it will consider the action failed if it does not get a response
from the other node in this time (after considering the action's
own timeout). The "correct" value will depend on the speed and load of your
network and cluster nodes.
| dc-deadtime | 20s |
indexterm:[dc-deadtime,Cluster Option]
indexterm:[Cluster,Option,dc-deadtime]
How long to wait for a response from other nodes during startup.
The "correct" value will depend on the speed/load of your network and the type of switches used.
| cluster-recheck-interval | 15min |
indexterm:[cluster-recheck-interval,Cluster Option]
indexterm:[Cluster,Option,cluster-recheck-interval]
Polling interval for time-based changes to options, resource parameters and constraints.
The Cluster is primarily event-driven, but your configuration can have
elements that take effect based on the time of day. To ensure these changes
take effect, we can optionally poll the cluster's status for changes. A value
of 0 disables polling. Positive values are an interval (in seconds unless other
SI units are specified, e.g. 5min).
| cluster-ipc-limit | 500 |
indexterm:[cluster-ipc-limit,Cluster Option]
indexterm:[Cluster,Option,cluster-ipc-limit]
The maximum IPC message backlog before one cluster daemon will disconnect
another. This is of use in large clusters, for which a good value is the number
of resources in the cluster multiplied by the number of nodes. The default of
500 is also the minimum. Raise this if you see "Evicting client" messages for
cluster daemon PIDs in the logs.
| pe-error-series-max | -1 |
indexterm:[pe-error-series-max,Cluster Option]
indexterm:[Cluster,Option,pe-error-series-max]
The number of PE inputs resulting in ERRORs to save. Used when reporting problems.
A value of -1 means unlimited (report all).
| pe-warn-series-max | -1 |
indexterm:[pe-warn-series-max,Cluster Option]
indexterm:[Cluster,Option,pe-warn-series-max]
The number of PE inputs resulting in WARNINGs to save. Used when reporting problems.
A value of -1 means unlimited (report all).
| pe-input-series-max | -1 |
indexterm:[pe-input-series-max,Cluster Option]
indexterm:[Cluster,Option,pe-input-series-max]
The number of "normal" PE inputs to save. Used when reporting problems.
A value of -1 means unlimited (report all).
| placement-strategy | default |
indexterm:[placement-strategy,Cluster Option]
indexterm:[Cluster,Option,placement-strategy]
How the cluster should allocate resources to nodes (see <<s-utilization>>).
Allowed values are +default+, +utilization+, +balanced+, and +minimal+.
| node-health-strategy | none |
indexterm:[node-health-strategy,Cluster Option]
indexterm:[Cluster,Option,node-health-strategy]
How the cluster should react to node health attributes (see <<s-node-health>>).
Allowed values are +none+, +migrate-on-red+, +only-green+, +progressive+, and
+custom+.
| node-health-base | 0 |
indexterm:[node-health-base,Cluster Option]
indexterm:[Cluster,Option,node-health-base]
The base health score assigned to a node. Only used when
+node-health-strategy+ is +progressive+.
| node-health-green | 0 |
indexterm:[node-health-green,Cluster Option]
indexterm:[Cluster,Option,node-health-green]
The score to use for a node health attribute whose value is +green+.
Only used when +node-health-strategy+ is +progressive+ or +custom+.
| node-health-yellow | 0 |
indexterm:[node-health-yellow,Cluster Option]
indexterm:[Cluster,Option,node-health-yellow]
The score to use for a node health attribute whose value is +yellow+.
Only used when +node-health-strategy+ is +progressive+ or +custom+.
| node-health-red | 0 |
indexterm:[node-health-red,Cluster Option]
indexterm:[Cluster,Option,node-health-red]
The score to use for a node health attribute whose value is +red+.
Only used when +node-health-strategy+ is +progressive+ or +custom+.
| remove-after-stop | FALSE |
indexterm:[remove-after-stop,Cluster Option]
indexterm:[Cluster,Option,remove-after-stop]
_Advanced Use Only:_ Should the cluster remove resources from the LRM after
they are stopped? Values other than the default are, at best, poorly tested and
potentially dangerous.
| startup-fencing | TRUE |
indexterm:[startup-fencing,Cluster Option]
indexterm:[Cluster,Option,startup-fencing]
_Advanced Use Only:_ Should the cluster shoot unseen nodes?
Not using the default is very unsafe!
| election-timeout | 2min |
indexterm:[election-timeout,Cluster Option]
indexterm:[Cluster,Option,election-timeout]
_Advanced Use Only:_ If you need to adjust this value, it probably indicates
the presence of a bug.
| shutdown-escalation | 20min |
indexterm:[shutdown-escalation,Cluster Option]
indexterm:[Cluster,Option,shutdown-escalation]
_Advanced Use Only:_ If you need to adjust this value, it probably indicates
the presence of a bug.
| join-integration-timeout | 3min |
indexterm:[join-integration-timeout,Cluster Option]
indexterm:[Cluster,Option,join-integration-timeout]
_Advanced Use Only:_ If you need to adjust this value, it probably indicates
the presence of a bug.
| join-finalization-timeout | 30min |
indexterm:[join-finalization-timeout,Cluster Option]
indexterm:[Cluster,Option,join-finalization-timeout]
_Advanced Use Only:_ If you need to adjust this value, it probably indicates
the presence of a bug.
| transition-delay | 0s |
indexterm:[transition-delay,Cluster Option]
indexterm:[Cluster,Option,transition-delay]
_Advanced Use Only:_ Delay cluster recovery for the configured interval to
allow for additional/related events to occur. Useful if your configuration is
sensitive to the order in which ping updates arrive.
Enabling this option will slow down cluster recovery under
all conditions.
|=========================================================
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Resources.txt b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
index 84b8ca35ea..3f23151793 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
@@ -1,886 +1,886 @@
= Cluster Resources =
[[s-resource-primitive]]
== What is a Cluster Resource? ==
indexterm:[Resource]
A resource is a service made highly available by a cluster.
The simplest type of resource, a 'primitive' resource, is described
in this chapter. More complex forms, such as groups and clones,
are described in later chapters.
Every primitive resource has a 'resource agent'. A resource agent is an
external program that abstracts the service it provides and present a
consistent view to the cluster.
This allows the cluster to be agnostic about the resources it manages.
The cluster doesn't need to understand how the resource works because
it relies on the resource agent to do the right thing when given a
`start`, `stop` or `monitor` command. For this reason, it is crucial that
resource agents are well-tested.
Typically, resource agents come in the form of shell scripts. However,
they can be written using any technology (such as C, Python or Perl)
that the author is comfortable with.
[[s-resource-supported]]
== Resource Classes ==
indexterm:[Resource,class]
Pacemaker supports several classes of agents:
* OCF
* LSB
* Upstart
* Systemd
* Service
* Fencing
* Nagios Plugins
=== Open Cluster Framework ===
indexterm:[Resource,OCF]
indexterm:[OCF,Resources]
indexterm:[Open Cluster Framework,Resources]
The OCF standard
footnote:[See
http://www.opencf.org/cgi-bin/viewcvs.cgi/specs/ra/resource-agent-api.txt?rev=HEAD
-- at least as it relates to resource agents. The Pacemaker implementation has
been somewhat extended from the OCF specs, but none of those changes are
incompatible with the original OCF specification.]
is basically an extension of the Linux Standard Base conventions for
init scripts to:
* support parameters,
* make them self-describing, and
* make them extensible
OCF specs have strict definitions of the exit codes that actions must return.
footnote:[
The resource-agents source code includes the `ocf-tester` script, which
can be useful in this regard.
]
The cluster follows these specifications exactly, and giving the wrong
exit code will cause the cluster to behave in ways you will likely
find puzzling and annoying. In particular, the cluster needs to
distinguish a completely stopped resource from one which is in some
erroneous and indeterminate state.
Parameters are passed to the resource agent as environment variables, with the
special prefix +OCF_RESKEY_+. So, a parameter which the user thinks
of as +ip+ will be passed to the resource agent as +OCF_RESKEY_ip+. The
number and purpose of the parameters is left to the resource agent; however,
the resource agent should use the `meta-data` command to advertise any that it
supports.
The OCF class is the most preferred as it is an industry standard,
highly flexible (allowing parameters to be passed to agents in a
non-positional manner) and self-describing.
For more information, see the
http://www.linux-ha.org/wiki/OCF_Resource_Agents[reference] and
the 'Resource Agents' chapter of 'Pacemaker Administration'.
=== Linux Standard Base ===
indexterm:[Resource,LSB]
indexterm:[LSB,Resources]
indexterm:[Linux Standard Base,Resources]
'LSB' resource agents are rather known as 'init scripts' (service startup
scripts), located in +/etc/init.d+.
Commonly, they are provided by the OS distribution and, in order to be used
with the cluster, they must conform to the LSB Spec.
footnote:[
See
http://refspecs.linux-foundation.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
for the LSB Spec as it relates to init scripts.
]
[WARNING]
====
Many distributions or particular software packages claim LSB compliance
but ship with broken init scripts. For details on how to check whether
your init script is LSB-compatible, see the 'Resource Agents' chapter of
'Pacemaker Administration'. Common problematic violations of the LSB
standard include:
* Not implementing the +status+ operation at all
* Not observing the correct exit status codes for
+start+/+stop+/+status+ actions
* Starting a started resource returns an error
* Stopping a stopped resource returns an error
Since the LSB standard is pragmatic enough so as _not_ to elaborate
on clean and reliable (busy-waiting-free) service dependency chains beyond
symbolic system facilities names to order against (one of the strongest
guarantees set forth is with _syslog_ in particular, denoting that,
when satisfied, it's actually _operational_ -- something not demanded
universally with the standard) and because explicit dependency-based
ordering is crucial for stacked HA applications, additionally this
imminent setback, possibly rooted deeper in the lack of synchronization
after initial forking in daemons themselves (something that currently
spoils also Pacemaker's own user-facing ones) and hence nothing init
scripts alone could be blamed for, stands out:
* Insufficient causality discreetness on either service start-up (for
the dependency chains, it's rather essential the service is also
_operational_, with the minimal viable interpretation being that
subsequent +status+ returns success but preferably in the strict
sense, once the respective init script invocation finishes with
success) or shutdown (ditto with no child processes left behind)
footnote:[
There's an inherent difference between _started_ and _ready_ state
of the service at hand, see discussion at
https://jdebp.eu/FGA/unix-daemon-readiness-protocol-problems.html
also showing how suitably prepared <<s-resource-supported-systemd,systemd
resources>> may possibly improve on this through a native arrangement scheme.
]
====
[IMPORTANT]
====
Remember to make sure the computer is _not_ configured to start any
services at boot time -- that should be controlled by the cluster.
====
[[s-resource-supported-systemd]]
=== Systemd ===
indexterm:[Resource,Systemd]
indexterm:[Systemd,Resources]
Some newer distributions have replaced the old
http://en.wikipedia.org/wiki/Init#SysV-style["SysV"] style of
initialization daemons and scripts with an alternative called
http://www.freedesktop.org/wiki/Software/systemd[Systemd].
Pacemaker is able to manage these services _if they are present_.
Instead of init scripts, systemd has 'unit files'. Generally, the
services (unit files) are provided by the OS distribution, but there
are online guides for converting from init scripts.
footnote:[For example,
http://0pointer.de/blog/projects/systemd-for-admins-3.html]
[IMPORTANT]
====
Remember to make sure the computer is _not_ configured to start any
services at boot time -- that should be controlled by the cluster.
====
=== Upstart ===
indexterm:[Resource,Upstart]
indexterm:[Upstart,Resources]
Some newer distributions have replaced the old
http://en.wikipedia.org/wiki/Init#SysV-style["SysV"] style of
initialization daemons (and scripts) with an alternative called
http://upstart.ubuntu.com/[Upstart].
Pacemaker is able to manage these services _if they are present_.
Instead of init scripts, upstart has 'jobs'. Generally, the
services (jobs) are provided by the OS distribution.
[IMPORTANT]
====
Remember to make sure the computer is _not_ configured to start any
services at boot time -- that should be controlled by the cluster.
====
=== System Services ===
indexterm:[Resource,System Services]
indexterm:[System Service,Resources]
Since there are various types of system services (+systemd+,
+upstart+, and +lsb+), Pacemaker supports a special +service+ alias which
intelligently figures out which one applies to a given cluster node.
This is particularly useful when the cluster contains a mix of
+systemd+, +upstart+, and +lsb+.
In order, Pacemaker will try to find the named service as:
. an LSB init script
. a Systemd unit file
. an Upstart job
=== STONITH ===
indexterm:[Resource,STONITH]
indexterm:[STONITH,Resources]
The STONITH class is used exclusively for fencing-related resources. This is
discussed later in <<ch-stonith>>.
=== Nagios Plugins ===
indexterm:[Resource,Nagios Plugins]
indexterm:[Nagios Plugins,Resources]
Nagios Plugins
footnote:[The project has two independent forks, hosted at
https://www.nagios-plugins.org/ and https://www.monitoring-plugins.org/. Output
from both projects' plugins is similar, so plugins from either project can be
used with pacemaker.]
allow us to monitor services on remote hosts.
Pacemaker is able to do remote monitoring with the plugins _if they are
present_.
A common use case is to configure them as resources belonging to a resource
container (usually a virtual machine), and the container will be restarted
if any of them has failed. Another use is to configure them as ordinary
resources to be used for monitoring hosts or services via the network.
The supported parameters are same as the long options of the plugin.
[[primitive-resource]]
== Resource Properties ==
These values tell the cluster which resource agent to use for the resource,
where to find that resource agent and what standards it conforms to.
.Properties of a Primitive Resource
-[width="95%",cols="1m,6<",options="header",align="center"]
+[width="95%",cols="1m,<6",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|Your name for the resource
indexterm:[id,Resource]
indexterm:[Resource,Property,id]
|class
|The standard the resource agent conforms to. Allowed values:
+lsb+, +nagios+, +ocf+, +service+, +stonith+, +systemd+, +upstart+
indexterm:[class,Resource]
indexterm:[Resource,Property,class]
|type
|The name of the Resource Agent you wish to use. E.g. +IPaddr+ or +Filesystem+
indexterm:[type,Resource]
indexterm:[Resource,Property,type]
|provider
|The OCF spec allows multiple vendors to supply the same
resource agent. To use the OCF resource agents supplied by
the Heartbeat project, you would specify +heartbeat+ here.
indexterm:[provider,Resource]
indexterm:[Resource,Property,provider]
|=========================================================
The XML definition of a resource can be queried with the `crm_resource` tool.
For example:
----
# crm_resource --resource Email --query-xml
----
might produce:
.A system resource definition
=====
[source,XML]
<primitive id="Email" class="service" type="exim"/>
=====
[NOTE]
=====
One of the main drawbacks to system services (LSB, systemd or
Upstart) resources is that they do not allow any parameters!
=====
////
See https://tools.ietf.org/html/rfc5737 for choice of example IP address
////
.An OCF resource definition
=====
[source,XML]
-------
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<instance_attributes id="Public-IP-params">
<nvpair id="Public-IP-ip" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
-------
=====
[[s-resource-options]]
== Resource Options ==
Resources have two types of options: 'meta-attributes' and 'instance attributes'.
Meta-attributes apply to any type of resource, while instance attributes
are specific to each resource agent.
=== Resource Meta-Attributes ===
Meta-attributes are used by the cluster to decide how a resource should
behave and can be easily set using the `--meta` option of the
`crm_resource` command.
.Meta-attributes of a Primitive Resource
-[width="95%",cols="2m,2,5<a",options="header",align="center"]
+[width="95%",cols="2m,2,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|priority
|0
|If not all resources can be active, the cluster will stop lower
priority resources in order to keep higher priority ones active.
indexterm:[priority,Resource Option]
indexterm:[Resource,Option,priority]
|target-role
|Started
-|What state should the cluster attempt to keep this resource in? Allowed values:
+a|What state should the cluster attempt to keep this resource in? Allowed values:
* +Stopped:+ Force the resource to be stopped
* +Started:+ Allow the resource to be started (and in the case of
<<s-resource-promotable,promotable clone resources>>, promoted to master if
appropriate)
* +Slave:+ Allow the resource to be started, but only in Slave mode if
the resource is <<s-resource-promotable,promotable>>
* +Master:+ Equivalent to +Started+
indexterm:[target-role,Resource Option]
indexterm:[Resource,Option,target-role]
|is-managed
|TRUE
|Is the cluster allowed to start and stop the resource? Allowed
values: +true+, +false+
indexterm:[is-managed,Resource Option]
indexterm:[Resource,Option,is-managed]
|resource-stickiness
|value of +resource-stickiness+ in the +rsc_defaults+ section
|How much does the resource prefer to stay where it is?
indexterm:[resource-stickiness,Resource Option]
indexterm:[Resource,Option,resource-stickiness]
|requires
|+quorum+ for resources with a +class+ of +stonith+,
otherwise +unfencing+ if unfencing is active in the cluster,
otherwise +fencing+ if +stonith-enabled+ is true, otherwise +quorum+
-|Conditions under which the resource can be started
+a|Conditions under which the resource can be started
Allowed values:
* +nothing:+ can always be started
* +quorum:+ The cluster can only start this resource if a majority of
the configured nodes are active
* +fencing:+ The cluster can only start this resource if a majority
of the configured nodes are active _and_ any failed or unknown nodes
have been <<ch-stonith,fenced>>
* +unfencing:+
The cluster can only start this resource if a majority
of the configured nodes are active _and_ any failed or unknown nodes
have been fenced _and_ only on nodes that have been
<<s-unfencing,unfenced>>
indexterm:[requires,Resource Option]
indexterm:[Resource,Option,requires]
|migration-threshold
|INFINITY
|How many failures may occur for this resource on a node, before this
node is marked ineligible to host this resource. A value of 0 indicates that
this feature is disabled (the node will never be marked ineligible); by
constrast, the cluster treats INFINITY (the default) as a very large but
finite number. This option has an effect only if the failed operation
specifies +on-fail+ as +restart+ (the default), and additionally for
failed +start+ operations, if the cluster property +start-failure-is-fatal+
is +false+.
indexterm:[migration-threshold,Resource Option]
indexterm:[Resource,Option,migration-threshold]
|failure-timeout
|0
|How many seconds to wait before acting as if the failure had not
occurred, and potentially allowing the resource back to the node on
which it failed. A value of 0 indicates that this feature is disabled.
As with any time-based actions, this is not guaranteed to be checked more
frequently than the value of +cluster-recheck-interval+ (see
<<s-cluster-options>>).
indexterm:[failure-timeout,Resource Option]
indexterm:[Resource,Option,failure-timeout]
|multiple-active
|stop_start
-|What should the cluster do if it ever finds the resource active on
+a|What should the cluster do if it ever finds the resource active on
more than one node? Allowed values:
* +block:+ mark the resource as unmanaged
* +stop_only:+ stop all active instances and leave them that way
* +stop_start:+ stop all active instances and start the resource in
one location only
indexterm:[multiple-active,Resource Option]
indexterm:[Resource,Option,multiple-active]
|allow-migrate
|TRUE for ocf:pacemaker:remote resources, FALSE otherwise
|Whether the cluster should try to "live migrate" this resource when it needs
to be moved (see <<s-migrating-resources>>)
|container-attribute-target
|
|Specific to bundle resources; see <<s-bundle-attributes>>
|remote-node
|
|The name of the Pacemaker Remote guest node this resource is associated with,
if any. If specified, this both enables the resource as a guest node and
defines the unique name used to identify the guest node. The guest must be
configured to run the Pacemaker Remote daemon when it is started. +WARNING:+
This value cannot overlap with any resource or node IDs.
|remote-port
|3121
|If +remote-node+ is specified, the port on the guest used for its
Pacemaker Remote connection. The Pacemaker Remote daemon on the guest must be
configured to listen on this port.
|remote-addr
|value of +remote-node+
|If +remote-node+ is specified, the IP address or hostname used to connect to
the guest via Pacemaker Remote. The Pacemaker Remote daemon on the guest
must be configured to accept connections on this address.
|remote-connect-timeout
|60s
|If +remote-node+ is specified, how long before a pending guest connection will
time out.
|=========================================================
As an example of setting resource options, if you performed the following
commands on an LSB Email resource:
-------
# crm_resource --meta --resource Email --set-parameter priority --parameter-value 100
# crm_resource -m -r Email -p multiple-active -v block
-------
the resulting resource definition might be:
.An LSB resource with cluster options
=====
[source,XML]
-------
<primitive id="Email" class="lsb" type="exim">
<meta_attributes id="Email-meta_attributes">
<nvpair id="Email-meta_attributes-priority" name="priority" value="100"/>
<nvpair id="Email-meta_attributes-multiple-active" name="multiple-active" value="block"/>
</meta_attributes>
</primitive>
-------
=====
[[s-resource-defaults]]
=== Setting Global Defaults for Resource Meta-Attributes ===
To set a default value for a resource option, add it to the
+rsc_defaults+ section with `crm_attribute`. For example,
----
# crm_attribute --type rsc_defaults --name is-managed --update false
----
would prevent the cluster from starting or stopping any of the
resources in the configuration (unless of course the individual
resources were specifically enabled by having their +is-managed+ set to
+true+).
=== Resource Instance Attributes ===
The resource agents of some resource classes (lsb, systemd and upstart 'not' among them)
can be given parameters which determine how they behave and which instance
of a service they control.
If your resource agent supports parameters, you can add them with the
`crm_resource` command. For example,
----
# crm_resource --resource Public-IP --set-parameter ip --parameter-value 192.0.2.2
----
would create an entry in the resource like this:
.An example OCF resource with instance attributes
=====
[source,XML]
-------
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
-------
=====
For an OCF resource, the result would be an environment variable
called +OCF_RESKEY_ip+ with a value of +192.0.2.2+.
The list of instance attributes supported by an OCF resource agent can be
found by calling the resource agent with the `meta-data` command.
The output contains an XML description of all the supported
attributes, their purpose and default values.
.Displaying the metadata for the Dummy resource agent template
=====
----
# export OCF_ROOT=/usr/lib/ocf
# $OCF_ROOT/resource.d/pacemaker/Dummy meta-data
----
[source,XML]
-------
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="Dummy" version="1.0">
<version>1.0</version>
<longdesc lang="en">
This is a Dummy Resource Agent. It does absolutely nothing except
keep track of whether its running or not.
Its purpose in life is for testing and to serve as a template for RA writers.
NB: Please pay attention to the timeouts specified in the actions
section below. They should be meaningful for the kind of resource
the agent manages. They should be the minimum advised timeouts,
but they shouldn't/cannot cover _all_ possible resource
instances. So, try to be neither overly generous nor too stingy,
but moderate. The minimum timeouts should never be below 10 seconds.
</longdesc>
<shortdesc lang="en">Example stateless resource agent</shortdesc>
<parameters>
<parameter name="state" unique="1">
<longdesc lang="en">
Location to store the resource state in.
</longdesc>
<shortdesc lang="en">State file</shortdesc>
<content type="string" default="/var/run/Dummy-default.state" />
</parameter>
<parameter name="fake" unique="0">
<longdesc lang="en">
Fake attribute that can be changed to cause a reload
</longdesc>
<shortdesc lang="en">Fake attribute that can be changed to cause a reload</shortdesc>
<content type="string" default="dummy" />
</parameter>
<parameter name="op_sleep" unique="1">
<longdesc lang="en">
Number of seconds to sleep during operations. This can be used to test how
the cluster reacts to operation timeouts.
</longdesc>
<shortdesc lang="en">Operation sleep duration in seconds.</shortdesc>
<content type="string" default="0" />
</parameter>
</parameters>
<actions>
<action name="start" timeout="20" />
<action name="stop" timeout="20" />
<action name="monitor" timeout="20" interval="10" depth="0"/>
<action name="reload" timeout="20" />
<action name="migrate_to" timeout="20" />
<action name="migrate_from" timeout="20" />
<action name="validate-all" timeout="20" />
<action name="meta-data" timeout="5" />
</actions>
</resource-agent>
-------
=====
== Resource Operations ==
indexterm:[Resource,Action]
'Operations' are actions the cluster can perform on a resource by calling the
resource agent. Resource agents must support certain common operations such as
start, stop and monitor, and may implement any others.
Some operations are generated by the cluster itself, for example, stopping and
starting resources as needed.
You can configure operations in the cluster configuration. As an example, by
default the cluster will 'not' ensure your resources stay healthy once they are
started. footnote:[Currently, anyway. Automatic monitoring operations may be
added in a future version of Pacemaker.] To instruct the cluster to do this,
you need to add a +monitor+ operation to the resource's definition.
.An OCF resource with a recurring health check
=====
[source,XML]
-------
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<operations>
<op id="public-ip-check" name="monitor" interval="60s"/>
</operations>
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
-------
=====
.Properties of an Operation
-[width="95%",cols="2m,3,6<a",options="header",align="center"]
+[width="95%",cols="2m,3,<6",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the operation.
indexterm:[id,Action Property]
indexterm:[Action,Property,id]
|name
|
|The action to perform. This can be any action supported by the agent; common
values include +monitor+, +start+, and +stop+.
indexterm:[name,Action Property]
indexterm:[Action,Property,name]
|interval
|0
|How frequently (in seconds) to perform the operation. A value of 0 means never.
A positive value defines a 'recurring action', which is typically used with
<<s-resource-monitoring,monitor>>.
indexterm:[interval,Action Property]
indexterm:[Action,Property,interval]
|timeout
|
|How long to wait before declaring the action has failed
indexterm:[timeout,Action Property]
indexterm:[Action,Property,timeout]
|on-fail
|restart '(except for +stop+ operations, which default to' fence 'when
STONITH is enabled and' block 'otherwise)'
-|The action to take if this action ever fails. Allowed values:
+a|The action to take if this action ever fails. Allowed values:
* +ignore:+ Pretend the resource did not fail.
* +block:+ Don't perform any further operations on the resource.
* +stop:+ Stop the resource and do not start it elsewhere.
* +restart:+ Stop the resource and start it again (possibly on a different node).
* +fence:+ STONITH the node on which the resource failed.
* +standby:+ Move _all_ resources away from the node on which the resource failed.
indexterm:[on-fail,Action Property]
indexterm:[Action,Property,on-fail]
|enabled
|TRUE
|If +false+, ignore this operation definition. This is typically used to pause
a particular recurring +monitor+ operation; for instance, it can complement
the respective resource being unmanaged (+is-managed=false+), as this alone
will <<s-monitoring-unmanaged,not block any configured monitoring>>.
Disabling the operation does not suppress all actions of the given type.
Allowed values: +true+, +false+.
indexterm:[enabled,Action Property]
indexterm:[Action,Property,enabled]
|record-pending
|FALSE
|If +true+, the intention to perform the operation is recorded so that
GUIs and CLI tools can indicate that an operation is in progress.
This is best set as an _operation default_ (see next section).
Allowed values: +true+, +false+.
indexterm:[enabled,Action Property]
indexterm:[Action,Property,enabled]
|role
|
|Run the operation only on node(s) that the cluster thinks should be in
the specified role. This only makes sense for recurring +monitor+ operations.
Allowed (case-sensitive) values: +Stopped+, +Started+, and in the
case of <<s-resource-promotable,promotable clone resources>>, +Slave+ and +Master+.
indexterm:[role,Action Property]
indexterm:[Action,Property,role]
|=========================================================
[[s-resource-monitoring]]
=== Monitoring Resources for Failure ===
When Pacemaker first starts a resource, it runs one-time +monitor+ operations
(referred to as 'probes') to ensure the resource is running where it's
supposed to be, and not running where it's not supposed to be. (This behavior
can be affected by the +resource-discovery+ location constraint property.)
Other than those initial probes, Pacemaker will not (by default) check that
the resource continues to stay healthy. As in the example above, you must
configure +monitor+ operations explicitly to perform these checks.
By default, a +monitor+ operation will ensure that the resource is running
where it is supposed to. The +target-role+ property can be used for further
checking.
For example, if a resource has one +monitor+ operation with
+interval=10 role=Started+ and a second +monitor+ operation with
+interval=11 role=Stopped+, the cluster will run the first monitor on any nodes
it thinks 'should' be running the resource, and the second monitor on any nodes
that it thinks 'should not' be running the resource (for the truly paranoid,
who want to know when an administrator manually starts a service by mistake).
[[s-monitoring-unmanaged]]
=== Monitoring Resources When Administration is Disabled ===
Recurring +monitor+ operations behave differently under various administrative
settings:
* When a resource is unmanaged (by setting +is-managed=false+): No monitors
will be stopped.
+
If the unmanaged resource is stopped on a node where the cluster thinks it
should be running, the cluster will detect and report that it is not, but it
will not consider the monitor failed, and will not try to start the resource
until it is managed again.
+
Starting the unmanaged resource on a different node is strongly discouraged
and will at least cause the cluster to consider the resource failed, and
may require the resource's +target-role+ to be set to +Stopped+ then +Started+
to be recovered.
* When a node is put into standby: All resources will be moved away from the
node, and all +monitor+ operations will be stopped on the node, except those
specifying +role+ as +Stopped+. Such rather atypical monitoring will
consequently be started on the node if appropriate.
* When the cluster is put into maintenance mode: All resources will be marked
as unmanaged. All monitor operations will be stopped, except those with
specifying +role+ as +Stopped+. As with single unmanaged resources, starting
a resource on a node other than where the cluster expects it to be will
cause problems.
[[s-operation-defaults]]
=== Setting Global Defaults for Operations ===
You can change the global default values for operation properties
in a given cluster. These are defined in an +op_defaults+ section
of the CIB's +configuration+ section, and can be set with `crm_attribute`.
For example,
----
# crm_attribute --type op_defaults --name timeout --update 20s
----
would default each operation's +timeout+ to 20 seconds. If an
operation's definition also includes a value for +timeout+, then that
value would be used for that operation instead.
=== When Implicit Operations Take a Long Time ===
The cluster will always perform a number of implicit operations: +start+,
+stop+ and a non-recurring +monitor+ operation used at startup to check
whether the resource is already active. If one of these is taking too long,
then you can create an entry for them and specify a longer timeout.
.An OCF resource with custom timeouts for its implicit actions
=====
[source,XML]
-------
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<operations>
<op id="public-ip-startup" name="monitor" interval="0" timeout="90s"/>
<op id="public-ip-start" name="start" interval="0" timeout="180s"/>
<op id="public-ip-stop" name="stop" interval="0" timeout="15min"/>
</operations>
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
-------
=====
=== Multiple Monitor Operations ===
Provided no two operations (for a single resource) have the same name
and interval, you can have as many +monitor+ operations as you like.
In this way, you can do a superficial health check every minute and
progressively more intense ones at higher intervals.
To tell the resource agent what kind of check to perform, you need to
provide each monitor with a different value for a common parameter.
The OCF standard creates a special parameter called +OCF_CHECK_LEVEL+
for this purpose and dictates that it is "made available to the
resource agent without the normal +OCF_RESKEY+ prefix".
Whatever name you choose, you can specify it by adding an
+instance_attributes+ block to the +op+ tag. It is up to each
resource agent to look for the parameter and decide how to use it.
.An OCF resource with two recurring health checks, performing different levels of checks specified via +OCF_CHECK_LEVEL+.
=====
[source,XML]
-------
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<operations>
<op id="public-ip-health-60" name="monitor" interval="60">
<instance_attributes id="params-public-ip-depth-60">
<nvpair id="public-ip-depth-60" name="OCF_CHECK_LEVEL" value="10"/>
</instance_attributes>
</op>
<op id="public-ip-health-300" name="monitor" interval="300">
<instance_attributes id="params-public-ip-depth-300">
<nvpair id="public-ip-depth-300" name="OCF_CHECK_LEVEL" value="20"/>
</instance_attributes>
</op>
</operations>
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-level" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
-------
=====
=== Disabling a Monitor Operation ===
The easiest way to stop a recurring monitor is to just delete it.
However, there can be times when you only want to disable it
temporarily. In such cases, simply add +enabled=false+ to the
operation's definition.
.Example of an OCF resource with a disabled health check
=====
[source,XML]
-------
<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
<operations>
<op id="public-ip-check" name="monitor" interval="60s" enabled="false"/>
</operations>
<instance_attributes id="params-public-ip">
<nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/>
</instance_attributes>
</primitive>
-------
=====
This can be achieved from the command line by executing:
----
# cibadmin --modify --xml-text '<op id="public-ip-check" enabled="false"/>'
----
Once you've done whatever you needed to do, you can then re-enable it with
----
# cibadmin --modify --xml-text '<op id="public-ip-check" enabled="true"/>'
----
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Rules.txt b/doc/Pacemaker_Explained/en-US/Ch-Rules.txt
index 6e39ba27a8..af05d7b8f4 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Rules.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Rules.txt
@@ -1,642 +1,642 @@
= Rules =
////
We prefer [[ch-rules]], but older versions of asciidoc don't deal well
with that construct for chapter headings
////
anchor:ch-rules[Chapter 8, Rules]
indexterm:[Resource,Constraint,Rule]
Rules can be used to make your configuration more dynamic. One common
example is to set one value for +resource-stickiness+ during working
hours, to prevent resources from being moved back to their most
preferred location, and another on weekends when no-one is around to
notice an outage.
Another use of rules might be to assign machines to different
processing groups (using a node attribute) based on time and to then
use that attribute when creating location constraints.
Each rule can contain a number of expressions, date-expressions and
even other rules. The results of the expressions are combined based
on the rule's +boolean-op+ field to determine if the rule ultimately
evaluates to +true+ or +false+. What happens next depends on the
context in which the rule is being used.
== Rule Properties ==
.Properties of a Rule
-[width="95%",cols="2m,1,5<",options="header",align="center"]
+[width="95%",cols="2m,1,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the rule (required)
indexterm:[id,Constraint Rule]
indexterm:[Constraint,Rule,id]
|role
|+Started+
|Limits the rule to apply only when the resource is in the specified
role. Allowed values are +Started+, +Slave+, and +Master+. A rule
with +role="Master"+ cannot determine the initial location of a
clone instance and will only affect which of the active instances
will be promoted.
indexterm:[role,Constraint Rule]
indexterm:[Constraint,Rule,role]
|score
|
|The score to apply if the rule evaluates to +true+. Limited to use in
rules that are part of location constraints.
indexterm:[score,Constraint Rule]
indexterm:[Constraint,Rule,score]
|score-attribute
|
|The node attribute to look up and use as a score if the rule
evaluates to +true+. Limited to use in rules that are part of
location constraints.
indexterm:[score-attribute,Constraint Rule]
indexterm:[Constraint,Rule,score-attribute]
|boolean-op
|+and+
|How to combine the result of multiple expression objects. Allowed
values are +and+ and +or+.
indexterm:[boolean-op,Constraint Rule]
indexterm:[Constraint,Rule,boolean-op]
|=========================================================
== Node Attribute Expressions ==
indexterm:[Resource,Constraint,Attribute Expression]
Expression objects are used to control a resource based on the
attributes defined by a node or nodes.
.Properties of an Expression
-[width="95%",cols="2m,1,5<a",options="header",align="center"]
+[width="95%",cols="2m,1,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the expression (required)
indexterm:[id,Constraint Expression]
indexterm:[Constraint,Attribute Expression,id]
|attribute
|
|The node attribute to test (required)
indexterm:[attribute,Constraint Expression]
indexterm:[Constraint,Attribute Expression,attribute]
|type
|+string+
|Determines how the value(s) should be tested. Allowed values are
+string+, +integer+, and +version+.
indexterm:[type,Constraint Expression]
indexterm:[Constraint,Attribute Expression,type]
|operation
|
-|The comparison to perform (required). Allowed values:
+a|The comparison to perform (required). Allowed values:
* +lt:+ True if the value of the node's +attribute+ is less than +value+
* +gt:+ True if the value of the node's +attribute+ is greater than +value+
* +lte:+ True if the value of the node's +attribute+ is less than or equal to +value+
* +gte:+ True if the value of the node's +attribute+ is greater than or equal to +value+
* +eq:+ True if the value of the node's +attribute+ is equal to +value+
* +ne:+ True if the value of the node's +attribute+ is not equal to +value+
* +defined:+ True if the node has the named attribute
* +not_defined:+ True if the node does not have the named attribute
indexterm:[operation,Constraint Expression]
indexterm:[Constraint,Attribute Expression,operation]
|value
|
|User-supplied value for comparison (required)
indexterm:[value,Constraint Expression]
indexterm:[Constraint,Attribute Expression,value]
|value-source
|+literal+
-|How the +value+ is derived. Allowed values:
+a|How the +value+ is derived. Allowed values:
* +literal+: +value+ is a literal string to compare against
* +param+: +value+ is the name of a resource parameter to compare against (only
valid in location constraints)
* +meta+: +value+ is the name of a resource meta-attribute to compare against
(only valid in location constraints)
indexterm:[value,Constraint Expression]
indexterm:[Constraint,Attribute Expression,value]
|=========================================================
In addition to any attributes added by the administrator, the cluster defines
special, built-in node attributes for each node that can also be used.
.Built-in node attributes
-[width="95%",cols="1m,5<a",options="header",align="center"]
+[width="95%",cols="1m,<5",options="header",align="center"]
|=========================================================
|Name
|Value
|#uname
|Node <<s-node-name,name>>
|#id
|Node ID
|#kind
|Node type. Possible values are +cluster+, +remote+, and +container+. Kind is
+remote+ for Pacemaker Remote nodes created with the +ocf:pacemaker:remote+
resource, and +container+ for Pacemaker Remote guest nodes and bundle nodes
|#is_dc
|"true" if this node is a Designated Controller (DC), "false" otherwise
|#cluster-name
|The value of the +cluster-name+ cluster property, if set
|#site-name
|The value of the +site-name+ cluster property, if set, otherwise identical to
+#cluster-name+
|#role
-|The role the relevant promotable clone resource has on this node. Valid only within
+a|The role the relevant promotable clone resource has on this node. Valid only within
a rule for a location constraint for a promotable clone resource.
////
// if uncommenting, put a pipe in front of first two lines
#ra-version
The installed version of the resource agent on the node, as defined
by the +version+ attribute of the +resource-agent+ tag in the agent's
metadata. Valid only within rules controlling resource options. This can be
useful during rolling upgrades of a backward-incompatible resource agent.
'(coming in x.x.x)'
////
|=========================================================
== Time- and Date-Based Expressions ==
indexterm:[Time Based Expressions]
indexterm:[Resource,Constraint,Date/Time Expression]
As the name suggests, +date_expressions+ are used to control a
resource or cluster option based on the current date/time. They may
contain an optional +date_spec+ and/or +duration+ object depending on
the context.
.Properties of a Date Expression
-[width="95%",cols="2m,5<a",options="header",align="center"]
+[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|start
|A date/time conforming to the http://en.wikipedia.org/wiki/ISO_8601[ISO8601]
specification.
indexterm:[start,Constraint Expression]
indexterm:[Constraint,Date/Time Expression,start]
|end
|A date/time conforming to the http://en.wikipedia.org/wiki/ISO_8601[ISO8601]
specification. Can be inferred by supplying a value for +start+ and a
+duration+.
indexterm:[end,Constraint Expression]
indexterm:[Constraint,Date/Time Expression,end]
|operation
-|Compares the current date/time with the start and/or end date,
+a|Compares the current date/time with the start and/or end date,
depending on the context. Allowed values:
* +gt:+ True if the current date/time is after +start+
* +lt:+ True if the current date/time is before +end+
* +in_range:+ True if the current date/time is after +start+ and before +end+
* +date_spec:+ True if the current date/time matches a +date_spec+ object
(described below)
indexterm:[operation,Constraint Expression]
indexterm:[Constraint,Date/Time Expression,operation]
|=========================================================
[NOTE]
======
As these comparisons (except for +date_spec+) include the time, the
+eq+, +neq+, +gte+ and +lte+ operators have not been implemented since
they would only be valid for a single second.
======
=== Date Specifications ===
indexterm:[Date Specification]
indexterm:[Resource,Constraint,Date Specification]
+date_spec+ objects are used to create cron-like expressions relating
to time. Each field can contain a single number or a single range.
Instead of defaulting to zero, any field not supplied is ignored.
For example, +monthdays="1"+ matches the first day of every month and
+hours="09-17"+ matches the hours between 9am and 5pm (inclusive).
At this time, multiple ranges (e.g. +weekdays="1,2"+ or
+weekdays="1-2,5-6"+) are not supported; depending on
demand, this might be implemented in a future release.
.Properties of a Date Specification
-[width="95%",cols="2m,5<",options="header",align="center"]
+[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the object
indexterm:[id,Date Specification]
indexterm:[Constraint,Date Specification,id]
|hours
|Allowed values: 0-23
indexterm:[hours,Date Specification]
indexterm:[Constraint,Date Specification,hours]
|monthdays
|Allowed values: 1-31 (depending on month and year)
indexterm:[monthdays,Date Specification]
indexterm:[Constraint,Date Specification,monthdays]
|weekdays
|Allowed values: 1-7 (1=Monday, 7=Sunday)
indexterm:[weekdays,Date Specification]
indexterm:[Constraint,Date Specification,weekdays]
|yeardays
|Allowed values: 1-366 (depending on the year)
indexterm:[yeardays,Date Specification]
indexterm:[Constraint,Date Specification,yeardays]
|months
|Allowed values: 1-12
indexterm:[months,Date Specification]
indexterm:[Constraint,Date Specification,months]
|weeks
|Allowed values: 1-53 (depending on weekyear)
indexterm:[weeks,Date Specification]
indexterm:[Constraint,Date Specification,weeks]
|years
|Year according to the Gregorian calendar
indexterm:[years,Date Specification]
indexterm:[Constraint,Date Specification,years]
|weekyears
|Year in which the week started; e.g. 1 January 2005
can be specified as '2005-001 Ordinal', '2005-01-01 Gregorian' or '2004-W53-6
Weekly' and thus would match +years="2005"+ or +weekyears="2004"+
indexterm:[weekyears,Date Specification]
indexterm:[Constraint,Date Specification,weekyears]
|moon
|Allowed values are 0-7 (0 is new, 4 is full moon). Seriously, you can
use this. This was implemented to demonstrate the ease with which new
comparisons could be added.
indexterm:[moon,Date Specification]
indexterm:[Constraint,Date Specification,moon]
|=========================================================
=== Durations ===
indexterm:[Duration]
indexterm:[Resource,Constraint,Duration]
Durations are used to calculate a value for +end+ when one is not
supplied to +in_range+ operations. They contain the same fields as
+date_spec+ objects but without the limitations (e.g. you can have a
duration of 19 months). As with +date_specs+, any field not supplied is
ignored.
=== Sample Time-Based Expressions ===
A small sample of how time-based expressions can be used:
////
On older versions of asciidoc, the [source] directive makes the title disappear
////
.True if now is any time in the year 2005
====
[source,XML]
----
<rule id="rule1">
<date_expression id="date_expr1" start="2005-001" operation="in_range">
<duration years="1"/>
</date_expression>
</rule>
----
====
.Equivalent expression
====
[source,XML]
----
<rule id="rule2">
<date_expression id="date_expr2" operation="date_spec">
<date_spec years="2005"/>
</date_expression>
</rule>
----
====
.9am-5pm Monday-Friday
====
[source,XML]
-------
<rule id="rule3">
<date_expression id="date_expr3" operation="date_spec">
<date_spec hours="9-16" days="1-5"/>
</date_expression>
</rule>
-------
====
Please note that the +16+ matches up to +16:59:59+, as the numeric
value (hour) still matches!
.9am-6pm Monday through Friday or anytime Saturday
====
[source,XML]
-------
<rule id="rule4" boolean-op="or">
<date_expression id="date_expr4-1" operation="date_spec">
<date_spec hours="9-16" days="1-5"/>
</date_expression>
<date_expression id="date_expr4-2" operation="date_spec">
<date_spec days="6"/>
</date_expression>
</rule>
-------
====
.9am-5pm or 9pm-12am Monday through Friday
====
[source,XML]
-------
<rule id="rule5" boolean-op="and">
<rule id="rule5-nested1" boolean-op="or">
<date_expression id="date_expr5-1" operation="date_spec">
<date_spec hours="9-16"/>
</date_expression>
<date_expression id="date_expr5-2" operation="date_spec">
<date_spec hours="21-23"/>
</date_expression>
</rule>
<date_expression id="date_expr5-3" operation="date_spec">
<date_spec days="1-5"/>
</date_expression>
</rule>
-------
====
.Mondays in March 2005
====
[source,XML]
-------
<rule id="rule6" boolean-op="and">
<date_expression id="date_expr6-1" operation="date_spec">
<date_spec weekdays="1"/>
</date_expression>
<date_expression id="date_expr6-2" operation="in_range"
start="2005-03-01" end="2005-04-01"/>
</rule>
-------
====
[NOTE]
======
Because no time is specified with the above dates, 00:00:00 is implied. This
means that the range includes all of 2005-03-01 but none of 2005-04-01.
You may wish to write +end="2005-03-31T23:59:59"+ to avoid confusion.
======
.A full moon on Friday the 13th
=====
[source,XML]
-------
<rule id="rule7" boolean-op="and">
<date_expression id="date_expr7" operation="date_spec">
<date_spec weekdays="5" monthdays="13" moon="4"/>
</date_expression>
</rule>
-------
=====
== Using Rules to Determine Resource Location ==
indexterm:[Rule,Determine Resource Location]
indexterm:[Resource,Location,Determine by Rules]
A location constraint may contain rules. When the constraint's outermost
rule evaluates to +false+, the cluster treats the constraint as if it were not
there. When the rule evaluates to +true+, the node's preference for running
the resource is updated with the score associated with the rule.
If this sounds familiar, it is because you have been using a simplified
syntax for location constraint rules already. Consider the following
location constraint:
.Prevent myApacheRsc from running on c001n03
=====
[source,XML]
-------
<rsc_location id="dont-run-apache-on-c001n03" rsc="myApacheRsc"
score="-INFINITY" node="c001n03"/>
-------
=====
This constraint can be more verbosely written as:
.Prevent myApacheRsc from running on c001n03 - expanded version
=====
[source,XML]
-------
<rsc_location id="dont-run-apache-on-c001n03" rsc="myApacheRsc">
<rule id="dont-run-apache-rule" score="-INFINITY">
<expression id="dont-run-apache-expr" attribute="#uname"
operation="eq" value="c00n03"/>
</rule>
</rsc_location>
-------
=====
The advantage of using the expanded form is that one can then add
extra clauses to the rule, such as limiting the rule such that it only
applies during certain times of the day or days of the week.
=== Location Rules Based on Other Node Properties ===
The expanded form allows us to match on node properties other than its name.
If we rated each machine's CPU power such that the cluster had the
following nodes section:
.A sample nodes section for use with score-attribute
=====
[source,XML]
-------
<nodes>
<node id="uuid1" uname="c001n01" type="normal">
<instance_attributes id="uuid1-custom_attrs">
<nvpair id="uuid1-cpu_mips" name="cpu_mips" value="1234"/>
</instance_attributes>
</node>
<node id="uuid2" uname="c001n02" type="normal">
<instance_attributes id="uuid2-custom_attrs">
<nvpair id="uuid2-cpu_mips" name="cpu_mips" value="5678"/>
</instance_attributes>
</node>
</nodes>
-------
=====
then we could prevent resources from running on underpowered machines with this rule:
[source,XML]
-------
<rule id="need-more-power-rule" score="-INFINITY">
<expression id="need-more-power-expr" attribute="cpu_mips"
operation="lt" value="3000"/>
</rule>
-------
=== Using +score-attribute+ Instead of +score+ ===
When using +score-attribute+ instead of +score+, each node matched by
the rule has its score adjusted differently, according to its value
for the named node attribute. Thus, in the previous example, if a
rule used +score-attribute="cpu_mips"+, +c001n01+ would have its
preference to run the resource increased by +1234+ whereas +c001n02+
would have its preference increased by +5678+.
== Using Rules to Control Resource Options ==
Often some cluster nodes will be different from their peers. Sometimes,
these differences -- e.g. the location of a binary or the names of network
interfaces -- require resources to be configured differently depending
on the machine they're hosted on.
By defining multiple +instance_attributes+ objects for the resource
and adding a rule to each, we can easily handle these special cases.
In the example below, +mySpecialRsc+ will use eth1 and port 9999 when
run on +node1+, eth2 and port 8888 on +node2+ and default to eth0 and
port 9999 for all other nodes.
.Defining different resource options based on the node name
=====
[source,XML]
-------
<primitive id="mySpecialRsc" class="ocf" type="Special" provider="me">
<instance_attributes id="special-node1" score="3">
<rule id="node1-special-case" score="INFINITY" >
<expression id="node1-special-case-expr" attribute="#uname"
operation="eq" value="node1"/>
</rule>
<nvpair id="node1-interface" name="interface" value="eth1"/>
</instance_attributes>
<instance_attributes id="special-node2" score="2" >
<rule id="node2-special-case" score="INFINITY">
<expression id="node2-special-case-expr" attribute="#uname"
operation="eq" value="node2"/>
</rule>
<nvpair id="node2-interface" name="interface" value="eth2"/>
<nvpair id="node2-port" name="port" value="8888"/>
</instance_attributes>
<instance_attributes id="defaults" score="1" >
<nvpair id="default-interface" name="interface" value="eth0"/>
<nvpair id="default-port" name="port" value="9999"/>
</instance_attributes>
</primitive>
-------
=====
The order in which +instance_attributes+ objects are evaluated is
determined by their score (highest to lowest). If not supplied, score
defaults to zero, and objects with an equal score are processed in
listed order. If the +instance_attributes+ object has no rule
or a +rule+ that evaluates to +true+, then for any parameter the resource does
not yet have a value for, the resource will use the parameter values defined by
the +instance_attributes+.
For example, given the configuration above, if the resource is placed on node1:
. +special-node1+ has the highest score (3) and so is evaluated first;
its rule evaluates to +true+, so +interface+ is set to +eth1+.
. +special-node2+ is evaluated next with score 2, but its rule evaluates to +false+,
so it is ignored.
. +defaults+ is evaluated last with score 1, and has no rule, so its values
are examined; +interface+ is already defined, so the value here is not used,
but +port+ is not yet defined, so +port+ is set to +9999+.
== Using Rules to Control Cluster Options ==
indexterm:[Rule,Controlling Cluster Options]
indexterm:[Cluster,Setting Options with Rules]
Controlling cluster options is achieved in much the same manner as
specifying different resource options on different nodes.
The difference is that because they are cluster options, one cannot
(or should not, because they won't work) use attribute-based
expressions. The following example illustrates how to set a different
+resource-stickiness+ value during and outside work hours. This
allows resources to automatically move back to their most preferred
hosts, but at a time that (in theory) does not interfere with business
activities.
.Change +resource-stickiness+ during working hours
=====
[source,XML]
-------
<rsc_defaults>
<meta_attributes id="core-hours" score="2">
<rule id="core-hour-rule" score="0">
<date_expression id="nine-to-five-Mon-to-Fri" operation="date_spec">
<date_spec id="nine-to-five-Mon-to-Fri-spec" hours="9-16" weekdays="1-5"/>
</date_expression>
</rule>
<nvpair id="core-stickiness" name="resource-stickiness" value="INFINITY"/>
</meta_attributes>
<meta_attributes id="after-hours" score="1" >
<nvpair id="after-stickiness" name="resource-stickiness" value="0"/>
</meta_attributes>
</rsc_defaults>
-------
=====
[[s-rules-recheck]]
== Ensuring Time-Based Rules Take Effect ==
A Pacemaker cluster is an event-driven system. As such, it won't
recalculate the best place for resources to run unless something
(like a resource failure or configuration change) happens. This can
mean that a location constraint that only allows resource X to run
between 9am and 5pm is not enforced.
If you rely on time-based rules, the +cluster-recheck-interval+ cluster option
(which defaults to 15 minutes) is essential. This tells the cluster to
periodically recalculate the ideal state of the cluster.
For example, if you set +cluster-recheck-interval="5m"+, then sometime between
09:00 and 09:05 the cluster would notice that it needs to start resource X,
and between 17:00 and 17:05 it would realize that X needed to be stopped.
The timing of the actual start and stop actions depends on what other actions
the cluster may need to perform first.
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Status.txt b/doc/Pacemaker_Explained/en-US/Ch-Status.txt
index cc5eaa3ffe..e6394ad1a1 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Status.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Status.txt
@@ -1,372 +1,372 @@
= Status -- Here be dragons =
Most users never need to understand the contents of the status section
and can be happy with the output from `crm_mon`.
However for those with a curious inclination, this section attempts to
provide an overview of its contents.
== Node Status ==
indexterm:[Node,Status]
indexterm:[Status of a Node]
In addition to the cluster's configuration, the CIB holds an
up-to-date representation of each cluster node in the +status+ section.
.A bare-bones status entry for a healthy node *cl-virt-1*
======
[source,XML]
-----
<node_state id="1" uname="cl-virt-1" in_ccm="true" crmd="online" crm-debug-origin="do_update_resource" join="member" expected="member">
<transient_attributes id="1"/>
<lrm id="1"/>
</node_state>
-----
======
Users are highly recommended _not_ to modify any part of a node's
state _directly_. The cluster will periodically regenerate the entire
section from authoritative sources, so any changes should be done
with the tools appropriate to those sources.
.Authoritative Sources for State Information
-[width="95%",cols="1m,1<",options="header",align="center"]
+[width="95%",cols="1m,<1",options="header",align="center"]
|=========================================================
| CIB Object | Authoritative Source
|node_state|pacemaker-controld
|transient_attributes|pacemaker-attrd
|lrm|pacemaker-execd
|=========================================================
The fields used in the +node_state+ objects are named as they are
largely for historical reasons and are rooted in Pacemaker's origins
as the resource manager for the older Heartbeat project. They have remained
unchanged to preserve compatibility with older versions.
.Node Status Fields
-[width="95%",cols="1m,4<",options="header",align="center"]
+[width="95%",cols="1m,<4",options="header",align="center"]
|=========================================================
|Field |Description
| id |
indexterm:[id,Node Status]
indexterm:[Node,Status,id]
Unique identifier for the node. Corosync-based clusters use a numeric counter.
| uname |
indexterm:[uname,Node Status]
indexterm:[Node,Status,uname]
The node's name as known by the cluster
| in_ccm |
indexterm:[in_ccm,Node Status]
indexterm:[Node,Status,in_ccm]
Is the node a member at the cluster communication layer? Allowed values:
+true+, +false+.
| crmd |
indexterm:[crmd,Node Status]
indexterm:[Node,Status,crmd]
Is the node a member at the pacemaker layer? Allowed values: +online+,
+offline+.
| crm-debug-origin |
indexterm:[crm-debug-origin,Node Status]
indexterm:[Node,Status,crm-debug-origin]
The name of the source function that made the most recent change (for debugging
purposes).
| join |
indexterm:[join,Node Status]
indexterm:[Node,Status,join]
Does the node participate in hosting resources? Allowed values: +down+,
+pending+, +member+, +banned+.
| expected |
indexterm:[expected,Node Status]
indexterm:[Node,Status,expected]
Expected value for +join+.
|=========================================================
The cluster uses these fields to determine whether, at the node level, the
node is healthy or is in a failed state and needs to be fenced.
== Transient Node Attributes ==
Like regular <<s-node-attributes,node attributes>>, the name/value
pairs listed in the +transient_attributes+ section help to describe the
node. However they are forgotten by the cluster when the node goes offline.
This can be useful, for instance, when you want a node to be in standby mode
(not able to run resources) just until the next reboot.
In addition to any values the administrator sets, the cluster will
also store information about failed resources here.
.A set of transient node attributes for node *cl-virt-1*
======
[source,XML]
-----
<transient_attributes id="cl-virt-1">
<instance_attributes id="status-cl-virt-1">
<nvpair id="status-cl-virt-1-pingd" name="pingd" value="3"/>
<nvpair id="status-cl-virt-1-probe_complete" name="probe_complete" value="true"/>
<nvpair id="status-cl-virt-1-fail-count-pingd:0.monitor_30000" name="fail-count-pingd:0#monitor_30000" value="1"/>
<nvpair id="status-cl-virt-1-last-failure-pingd:0" name="last-failure-pingd:0" value="1239009742"/>
</instance_attributes>
</transient_attributes>
-----
======
In the above example, we can see that a monitor on the +pingd:0+ resource has
failed once, at 09:22:22 UTC 6 April 2009.
footnote:[
You can use the standard `date` command to print a human-readable version of
any seconds-since-epoch value, for example `date -d @1239009742`.
]
We also see that the node is connected to three *pingd* peers and that
all known resources have been checked for on this machine (+probe_complete+).
== Operation History ==
indexterm:[Operation History]
A node's resource history is held in the +lrm_resources+ tag (a child
of the +lrm+ tag). The information stored here includes enough
information for the cluster to stop the resource safely if it is
removed from the +configuration+ section. Specifically, the resource's
+id+, +class+, +type+ and +provider+ are stored.
.A record of the +apcstonith+ resource
======
[source,XML]
<lrm_resource id="apcstonith" type="apcmastersnmp" class="stonith"/>
======
Additionally, we store the last job for every combination of
+resource+, +action+ and +interval+. The concatenation of the values in
this tuple are used to create the id of the +lrm_rsc_op+ object.
.Contents of an +lrm_rsc_op+ job
-[width="95%",cols="2m,5<",options="header",align="center"]
+[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
| id |
indexterm:[id,Action Status]
indexterm:[Action,Status,id]
Identifier for the job constructed from the resource's +id+,
+operation+ and +interval+.
| call-id |
indexterm:[call-id,Action Status]
indexterm:[Action,Status,call-id]
The job's ticket number. Used as a sort key to determine the order in
which the jobs were executed.
| operation |
indexterm:[operation,Action Status]
indexterm:[Action,Status,operation]
The action the resource agent was invoked with.
| interval |
indexterm:[interval,Action Status]
indexterm:[Action,Status,interval]
The frequency, in milliseconds, at which the operation will be
repeated. A one-off job is indicated by 0.
| op-status |
indexterm:[op-status,Action Status]
indexterm:[Action,Status,op-status]
The job's status. Generally this will be either 0 (done) or -1
(pending). Rarely used in favor of +rc-code+.
| rc-code |
indexterm:[rc-code,Action Status]
indexterm:[Action,Status,rc-code]
The job's result. Refer to the 'Resource Agents' chapter of 'Pacemaker
Administration' for details on what the values here mean and how they are
interpreted.
| last-run |
indexterm:[last-run,Action Status]
indexterm:[Action,Status,last-run]
Machine-local date/time, in seconds since epoch,
at which the job was executed. For diagnostic purposes.
| last-rc-change |
indexterm:[last-rc-change,Action Status]
indexterm:[Action,Status,last-rc-change]
Machine-local date/time, in seconds since epoch,
at which the job first returned the current value of +rc-code+.
For diagnostic purposes.
| exec-time |
indexterm:[exec-time,Action Status]
indexterm:[Action,Status,exec-time]
Time, in milliseconds, that the job was running for.
For diagnostic purposes.
| queue-time |
indexterm:[queue-time,Action Status]
indexterm:[Action,Status,queue-time]
Time, in seconds, that the job was queued for in the LRMd.
For diagnostic purposes.
| crm_feature_set |
indexterm:[crm_feature_set,Action Status]
indexterm:[Action,Status,crm_feature_set]
The version which this job description conforms to. Used when
processing +op-digest+.
| transition-key |
indexterm:[transition-key,Action Status]
indexterm:[Action,Status,transition-key]
A concatenation of the job's graph action number, the graph number,
the expected result and the UUID of the controller instance that scheduled
it. This is used to construct +transition-magic+ (below).
| transition-magic |
indexterm:[transition-magic,Action Status]
indexterm:[Action,Status,transition-magic]
A concatenation of the job's +op-status+, +rc-code+ and
+transition-key+. Guaranteed to be unique for the life of the cluster
(which ensures it is part of CIB update notifications) and contains
all the information needed for the controller to correctly analyze and
process the completed job. Most importantly, the decomposed elements
tell the controller if the job entry was expected and whether it failed.
| op-digest |
indexterm:[op-digest,Action Status]
indexterm:[Action,Status,op-digest]
An MD5 sum representing the parameters passed to the job. Used to
detect changes to the configuration, to restart resources if
necessary.
| crm-debug-origin |
indexterm:[crm-debug-origin,Action Status]
indexterm:[Action,Status,crm-debug-origin]
The origin of the current values.
For diagnostic purposes.
|=========================================================
=== Simple Operation History Example ===
.A monitor operation (determines current state of the +apcstonith+ resource)
======
[source,XML]
-----
<lrm_resource id="apcstonith" type="apcmastersnmp" class="stonith">
<lrm_rsc_op id="apcstonith_monitor_0" operation="monitor" call-id="2"
rc-code="7" op-status="0" interval="0"
crm-debug-origin="do_update_resource" crm_feature_set="3.0.1"
op-digest="2e3da9274d3550dc6526fb24bfcbcba0"
transition-key="22:2:7:2668bbeb-06d5-40f9-936d-24cb7f87006a"
transition-magic="0:7;22:2:7:2668bbeb-06d5-40f9-936d-24cb7f87006a"
last-run="1239008085" last-rc-change="1239008085" exec-time="10" queue-time="0"/>
</lrm_resource>
-----
======
In the above example, the job is a non-recurring monitor operation
often referred to as a "probe" for the +apcstonith+ resource.
The cluster schedules probes for every configured resource on a node when
the node first starts, in order to determine the resource's current state
before it takes any further action.
From the +transition-key+, we can see that this was the 22nd action of
the 2nd graph produced by this instance of the controller
(2668bbeb-06d5-40f9-936d-24cb7f87006a).
The third field of the +transition-key+ contains a 7, which indicates
that the job expects to find the resource inactive. By looking at the +rc-code+
property, we see that this was the case.
As that is the only job recorded for this node, we can conclude that
the cluster started the resource elsewhere.
=== Complex Operation History Example ===
.Resource history of a +pingd+ clone with multiple jobs
======
[source,XML]
-----
<lrm_resource id="pingd:0" type="pingd" class="ocf" provider="pacemaker">
<lrm_rsc_op id="pingd:0_monitor_30000" operation="monitor" call-id="34"
rc-code="0" op-status="0" interval="30000"
crm-debug-origin="do_update_resource" crm_feature_set="3.0.1"
transition-key="10:11:0:2668bbeb-06d5-40f9-936d-24cb7f87006a"
...
last-run="1239009741" last-rc-change="1239009741" exec-time="10" queue-time="0"/>
<lrm_rsc_op id="pingd:0_stop_0" operation="stop"
crm-debug-origin="do_update_resource" crm_feature_set="3.0.1" call-id="32"
rc-code="0" op-status="0" interval="0"
transition-key="11:11:0:2668bbeb-06d5-40f9-936d-24cb7f87006a"
...
last-run="1239009741" last-rc-change="1239009741" exec-time="10" queue-time="0"/>
<lrm_rsc_op id="pingd:0_start_0" operation="start" call-id="33"
rc-code="0" op-status="0" interval="0"
crm-debug-origin="do_update_resource" crm_feature_set="3.0.1"
transition-key="31:11:0:2668bbeb-06d5-40f9-936d-24cb7f87006a"
...
last-run="1239009741" last-rc-change="1239009741" exec-time="10" queue-time="0" />
<lrm_rsc_op id="pingd:0_monitor_0" operation="monitor" call-id="3"
rc-code="0" op-status="0" interval="0"
crm-debug-origin="do_update_resource" crm_feature_set="3.0.1"
transition-key="23:2:7:2668bbeb-06d5-40f9-936d-24cb7f87006a"
...
last-run="1239008085" last-rc-change="1239008085" exec-time="20" queue-time="0"/>
</lrm_resource>
-----
======
When more than one job record exists, it is important to first sort
them by +call-id+ before interpreting them.
Once sorted, the above example can be summarized as:
. A non-recurring monitor operation returning 7 (not running), with a +call-id+ of 3
. A stop operation returning 0 (success), with a +call-id+ of 32
. A start operation returning 0 (success), with a +call-id+ of 33
. A recurring monitor returning 0 (success), with a +call-id+ of 34
The cluster processes each job record to build up a picture of the
resource's state. After the first and second entries, it is
considered stopped, and after the third it considered active.
Based on the last operation, we can tell that the resource is
currently active.
Additionally, from the presence of a +stop+ operation with a lower
+call-id+ than that of the +start+ operation, we can conclude that the
resource has been restarted. Specifically this occurred as part of
actions 11 and 31 of transition 11 from the controller instance with the key
+2668bbeb...+. This information can be helpful for locating the
relevant section of the logs when looking for the source of a failure.
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt b/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt
index 7c11c851fb..ff7cf5f98b 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt
@@ -1,939 +1,939 @@
= STONITH =
////
We prefer [[ch-stonith]], but older versions of asciidoc don't deal well
with that construct for chapter headings
////
anchor:ch-stonith[Chapter 13, STONITH]
indexterm:[STONITH, Configuration]
== What Is STONITH? ==
STONITH (an acronym for "Shoot The Other Node In The Head"), also called
'fencing', protects your data from being corrupted by rogue nodes or concurrent
access.
Just because a node is unresponsive, this doesn't mean it isn't
accessing your data. The only way to be 100% sure that your data is
safe, is to use STONITH so we can be certain that the node is truly
offline, before allowing the data to be accessed from another node.
STONITH also has a role to play in the event that a clustered service
cannot be stopped. In this case, the cluster uses STONITH to force the
whole node offline, thereby making it safe to start the service
elsewhere.
== What STONITH Device Should You Use? ==
It is crucial that the STONITH device can allow the cluster to
differentiate between a node failure and a network one.
The biggest mistake people make in choosing a STONITH device is to
use a remote power switch (such as many on-board IPMI controllers) that
shares power with the node it controls. In such cases, the cluster
cannot be sure if the node is really offline, or active and suffering
from a network fault.
Likewise, any device that relies on the machine being active (such as
SSH-based "devices" used during testing) are inappropriate.
== Special Treatment of STONITH Resources ==
STONITH resources are somewhat special in Pacemaker.
STONITH may be initiated by pacemaker or by other parts of the cluster
(such as resources like DRBD or DLM). To accommodate this, pacemaker
does not require the STONITH resource to be in the 'started' state
in order to be used, thus allowing reliable use of STONITH devices in such a
case.
All nodes have access to STONITH devices' definitions and instantiate them
on-the-fly when needed, but preference is given to 'verified' instances, which
are the ones that are 'started' according to the cluster's knowledge.
In the case of a cluster split, the partition with a verified instance
will have a slight advantage, because the STONITH daemon in the other partition
will have to hear from all its current peers before choosing a node to
perform the fencing.
Fencing resources do work the same as regular resources in some respects:
* +target-role+ can be used to enable or disable the resource
* Location constraints can be used to prevent a specific node from using the resource
[IMPORTANT]
===========
Currently there is a limitation that fencing resources may only have
one set of meta-attributes and one set of instance attributes. This
can be revisited if it becomes a significant limitation for people.
===========
See the table below or run `man pacemaker-fenced` to see special instance attributes
that may be set for any fencing resource, regardless of fence agent.
.Additional Properties of Fencing Resources
-[width="95%",cols="5m,2,3,10<a",options="header",align="center"]
+[width="95%",cols="5m,2,3,<10",options="header",align="center"]
|=========================================================
|Field
|Type
|Default
|Description
|stonith-timeout
|NA
|NA
-|Older versions used this to override the default period to wait for a STONITH (reboot, on, off) action to complete for this device.
+a|Older versions used this to override the default period to wait for a STONITH (reboot, on, off) action to complete for this device.
It has been replaced by the +pcmk_reboot_timeout+ and +pcmk_off_timeout+ properties.
indexterm:[stonith-timeout,Fencing]
indexterm:[Fencing,Property,stonith-timeout]
////
priority
integer
0
The priority of the STONITH resource. Devices are tried in order of highest priority to lowest.
indexterm:[priority,Fencing]
indexterm:[Fencing,Property,priority]
////
|provides
|string
|
|Any special capability provided by the fence device. Currently, only one such
capability is meaningful: +unfencing+ (see <<s-unfencing>>).
indexterm:[priority,Fencing]
indexterm:[Fencing,Property,priority]
|pcmk_host_map
|string
|
|A mapping of host names to ports numbers for devices that do not support host names.
Example: +node1:1;node2:2,3+ tells the cluster to use port 1 for
*node1* and ports 2 and 3 for *node2*.
indexterm:[pcmk_host_map,Fencing]
indexterm:[Fencing,Property,pcmk_host_map]
|pcmk_host_list
|string
|
|A list of machines controlled by this device (optional unless
+pcmk_host_check+ is +static-list+).
indexterm:[pcmk_host_list,Fencing]
indexterm:[Fencing,Property,pcmk_host_list]
|pcmk_host_check
|string
|dynamic-list
-|How to determine which machines are controlled by the device.
+a|How to determine which machines are controlled by the device.
Allowed values:
* +dynamic-list:+ query the device
* +static-list:+ check the +pcmk_host_list+ attribute
* +none:+ assume every device can fence every machine
indexterm:[pcmk_host_check,Fencing]
indexterm:[Fencing,Property,pcmk_host_check]
|pcmk_delay_max
|time
|0s
|Enable a random delay of up to the time specified before executing stonith
actions. This is sometimes used in two-node clusters to ensure that the
nodes don't fence each other at the same time. The overall delay introduced
by pacemaker is derived from this random delay value adding a static delay so
that the sum is kept below the maximum delay.
indexterm:[pcmk_delay_max,Fencing]
indexterm:[Fencing,Property,pcmk_delay_max]
|pcmk_delay_base
|time
|0s
|Enable a static delay before executing stonith actions. This can be used
e.g. in two-node clusters to ensure that the nodes don't fence each other,
by having separate fencing resources with different values. The node that is
fenced with the shorter delay will lose a fencing race. The overall delay
introduced by pacemaker is derived from this value plus a random delay such
that the sum is kept below the maximum delay.
indexterm:[pcmk_delay_base,Fencing]
indexterm:[Fencing,Property,pcmk_delay_base]
|pcmk_action_limit
|integer
|1
|The maximum number of actions that can be performed in parallel on this
device, if the cluster option +concurrent-fencing+ is +true+. -1 is unlimited.
indexterm:[pcmk_action_limit,Fencing]
indexterm:[Fencing,Property,pcmk_action_limit]
|pcmk_host_argument
|string
|port
|'Advanced use only.' Which parameter should be supplied to the resource agent
to identify the node to be fenced. Some devices do not support the standard
+port+ parameter or may provide additional ones. Use this to specify an
alternate, device-specific parameter. A value of +none+ tells the
cluster not to supply any additional parameters.
indexterm:[pcmk_host_argument,Fencing]
indexterm:[Fencing,Property,pcmk_host_argument]
|pcmk_reboot_action
|string
|reboot
|'Advanced use only.' The command to send to the resource agent in order to
reboot a node. Some devices do not support the standard commands or may provide
additional ones. Use this to specify an alternate, device-specific command.
indexterm:[pcmk_reboot_action,Fencing]
indexterm:[Fencing,Property,pcmk_reboot_action]
|pcmk_reboot_timeout
|time
|60s
|'Advanced use only.' Specify an alternate timeout to use for `reboot` actions
instead of the value of +stonith-timeout+. Some devices need much more or less
time to complete than normal. Use this to specify an alternate, device-specific
timeout.
indexterm:[pcmk_reboot_timeout,Fencing]
indexterm:[Fencing,Property,pcmk_reboot_timeout]
indexterm:[stonith-timeout,Fencing]
indexterm:[Fencing,Property,stonith-timeout]
|pcmk_reboot_retries
|integer
|2
|'Advanced use only.' The maximum number of times to retry the `reboot` command
within the timeout period. Some devices do not support multiple connections, and
operations may fail if the device is busy with another task, so Pacemaker will
automatically retry the operation, if there is time remaining. Use this option
to alter the number of times Pacemaker retries before giving up.
indexterm:[pcmk_reboot_retries,Fencing]
indexterm:[Fencing,Property,pcmk_reboot_retries]
|pcmk_off_action
|string
|off
|'Advanced use only.' The command to send to the resource agent in order to
shut down a node. Some devices do not support the standard commands or may provide
additional ones. Use this to specify an alternate, device-specific command.
indexterm:[pcmk_off_action,Fencing]
indexterm:[Fencing,Property,pcmk_off_action]
|pcmk_off_timeout
|time
|60s
|'Advanced use only.' Specify an alternate timeout to use for `off` actions
instead of the value of +stonith-timeout+. Some devices need much more or less
time to complete than normal. Use this to specify an alternate, device-specific
timeout.
indexterm:[pcmk_off_timeout,Fencing]
indexterm:[Fencing,Property,pcmk_off_timeout]
indexterm:[stonith-timeout,Fencing]
indexterm:[Fencing,Property,stonith-timeout]
|pcmk_off_retries
|integer
|2
|'Advanced use only.' The maximum number of times to retry the `off` command
within the timeout period. Some devices do not support multiple connections, and
operations may fail if the device is busy with another task, so Pacemaker will
automatically retry the operation, if there is time remaining. Use this option
to alter the number of times Pacemaker retries before giving up.
indexterm:[pcmk_off_retries,Fencing]
indexterm:[Fencing,Property,pcmk_off_retries]
|pcmk_list_action
|string
|list
|'Advanced use only.' The command to send to the resource agent in order to
list nodes. Some devices do not support the standard commands or may provide
additional ones. Use this to specify an alternate, device-specific command.
indexterm:[pcmk_list_action,Fencing]
indexterm:[Fencing,Property,pcmk_list_action]
|pcmk_list_timeout
|time
|60s
|'Advanced use only.' Specify an alternate timeout to use for `list` actions
instead of the value of +stonith-timeout+. Some devices need much more or less
time to complete than normal. Use this to specify an alternate, device-specific
timeout.
indexterm:[pcmk_list_timeout,Fencing]
indexterm:[Fencing,Property,pcmk_list_timeout]
|pcmk_list_retries
|integer
|2
|'Advanced use only.' The maximum number of times to retry the `list` command
within the timeout period. Some devices do not support multiple connections, and
operations may fail if the device is busy with another task, so Pacemaker will
automatically retry the operation, if there is time remaining. Use this option
to alter the number of times Pacemaker retries before giving up.
indexterm:[pcmk_list_retries,Fencing]
indexterm:[Fencing,Property,pcmk_list_retries]
|pcmk_monitor_action
|string
|monitor
|'Advanced use only.' The command to send to the resource agent in order to
report extended status. Some devices do not support the standard commands or may provide
additional ones. Use this to specify an alternate, device-specific command.
indexterm:[pcmk_monitor_action,Fencing]
indexterm:[Fencing,Property,pcmk_monitor_action]
|pcmk_monitor_timeout
|time
|60s
|'Advanced use only.' Specify an alternate timeout to use for `monitor` actions
instead of the value of +stonith-timeout+. Some devices need much more or less
time to complete than normal. Use this to specify an alternate, device-specific
timeout.
indexterm:[pcmk_monitor_timeout,Fencing]
indexterm:[Fencing,Property,pcmk_monitor_timeout]
|pcmk_monitor_retries
|integer
|2
|'Advanced use only.' The maximum number of times to retry the `monitor` command
within the timeout period. Some devices do not support multiple connections, and
operations may fail if the device is busy with another task, so Pacemaker will
automatically retry the operation, if there is time remaining. Use this option
to alter the number of times Pacemaker retries before giving up.
indexterm:[pcmk_monitor_retries,Fencing]
indexterm:[Fencing,Property,pcmk_monitor_retries]
|pcmk_status_action
|string
|status
|'Advanced use only.' The command to send to the resource agent in order to
report status. Some devices do not support the standard commands or may provide
additional ones. Use this to specify an alternate, device-specific command.
indexterm:[pcmk_status_action,Fencing]
indexterm:[Fencing,Property,pcmk_status_action]
|pcmk_status_timeout
|time
|60s
|'Advanced use only.' Specify an alternate timeout to use for `status` actions
instead of the value of +stonith-timeout+. Some devices need much more or less
time to complete than normal. Use this to specify an alternate, device-specific
timeout.
indexterm:[pcmk_status_timeout,Fencing]
indexterm:[Fencing,Property,pcmk_status_timeout]
|pcmk_status_retries
|integer
|2
|'Advanced use only.' The maximum number of times to retry the `status` command
within the timeout period. Some devices do not support multiple connections, and
operations may fail if the device is busy with another task, so Pacemaker will
automatically retry the operation, if there is time remaining. Use this option
to alter the number of times Pacemaker retries before giving up.
indexterm:[pcmk_status_retries,Fencing]
indexterm:[Fencing,Property,pcmk_status_retries]
|=========================================================
[[s-unfencing]]
== Unfencing ==
Most fence devices cut the power to the target. By contrast, fence devices that
perform 'fabric fencing' cut off a node's access to some critical resource,
such as a shared disk or a network switch.
With fabric fencing, it is expected that the cluster will fence the node, and
then a system administrator must manually investigate what went wrong, correct
any issues found, then reboot (or restart the cluster services on) the node.
Once the node reboots and rejoins the cluster, some fabric fencing devices
require that an explicit command to restore the node's access to the critical
resource. This capability is called 'unfencing' and is typically implemented
as the fence agent's +on+ command.
If any cluster resource has +requires+ set to +unfencing+, then that resource
will not be probed or started on a node until that node has been unfenced.
== Configuring STONITH ==
[NOTE]
===========
Higher-level configuration shells include functionality to simplify the
process below, particularly the step for deciding which parameters are
required. However since this document deals only with core
components, you should refer to the STONITH chapter of the
http://www.clusterlabs.org/doc/[Clusters from Scratch] guide for those details.
===========
. Find the correct driver:
+
----
# stonith_admin --list-installed
----
. Find the required parameters associated with the device
(replacing $AGENT_NAME with the name obtained from the previous step):
+
----
# stonith_admin --metadata --agent $AGENT_NAME
----
. Create a file called +stonith.xml+ containing a primitive resource
with a class of +stonith+, a type equal to the agent name obtained earlier,
and a parameter for each of the values returned in the previous step.
. If the device does not know how to fence nodes based on their uname,
you may also need to set the special +pcmk_host_map+ parameter. See
`man pacemaker-fenced` for details.
. If the device does not support the `list` command, you may also need
to set the special +pcmk_host_list+ and/or +pcmk_host_check+
parameters. See `man pacemaker-fenced` for details.
. If the device does not expect the victim to be specified with the
`port` parameter, you may also need to set the special
+pcmk_host_argument+ parameter. See `man pacemaker-fenced` for details.
. Upload it into the CIB using cibadmin:
+
----
# cibadmin -C -o resources --xml-file stonith.xml
----
. Set +stonith-enabled+ to true:
+
----
# crm_attribute -t crm_config -n stonith-enabled -v true
----
. Once the stonith resource is running, you can test it by executing the
following (although you might want to stop the cluster on that machine
first):
+
----
# stonith_admin --reboot nodename
----
=== Example STONITH Configuration ===
Assume we have an chassis containing four nodes and an IPMI device
active on 192.0.2.1. We would choose the `fence_ipmilan` driver,
and obtain the following list of parameters:
.Obtaining a list of STONITH Parameters
====
----
# stonith_admin --metadata -a fence_ipmilan
----
[source,XML]
----
<resource-agent name="fence_ipmilan" shortdesc="Fence agent for IPMI over LAN">
<symlink name="fence_ilo3" shortdesc="Fence agent for HP iLO3"/>
<symlink name="fence_ilo4" shortdesc="Fence agent for HP iLO4"/>
<symlink name="fence_idrac" shortdesc="Fence agent for Dell iDRAC"/>
<symlink name="fence_imm" shortdesc="Fence agent for IBM Integrated Management Module"/>
<longdesc>
</longdesc>
<vendor-url>
</vendor-url>
<parameters>
<parameter name="auth" unique="0" required="0">
<getopt mixed="-A"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="ipaddr" unique="0" required="1">
<getopt mixed="-a"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="passwd" unique="0" required="0">
<getopt mixed="-p"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="passwd_script" unique="0" required="0">
<getopt mixed="-S"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="lanplus" unique="0" required="0">
<getopt mixed="-P"/>
<content type="boolean"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="login" unique="0" required="0">
<getopt mixed="-l"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="action" unique="0" required="0">
<getopt mixed="-o"/>
<content type="string" default="reboot"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="timeout" unique="0" required="0">
<getopt mixed="-t"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="cipher" unique="0" required="0">
<getopt mixed="-C"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="method" unique="0" required="0">
<getopt mixed="-M"/>
<content type="string" default="onoff"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="power_wait" unique="0" required="0">
<getopt mixed="-T"/>
<content type="string" default="2"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="delay" unique="0" required="0">
<getopt mixed="-f"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="privlvl" unique="0" required="0">
<getopt mixed="-L"/>
<content type="string"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
<parameter name="verbose" unique="0" required="0">
<getopt mixed="-v"/>
<content type="boolean"/>
<shortdesc lang="en">
</shortdesc>
</parameter>
</parameters>
<actions>
<action name="on"/>
<action name="off"/>
<action name="reboot"/>
<action name="status"/>
<action name="diag"/>
<action name="list"/>
<action name="monitor"/>
<action name="metadata"/>
<action name="stop" timeout="20s"/>
<action name="start" timeout="20s"/>
</actions>
</resource-agent>
----
====
Based on that, we would create a STONITH resource fragment that might look
like this:
.An IPMI-based STONITH Resource
====
[source,XML]
----
<primitive id="Fencing" class="stonith" type="fence_ipmilan" >
<instance_attributes id="Fencing-params" >
<nvpair id="Fencing-passwd" name="passwd" value="testuser" />
<nvpair id="Fencing-login" name="login" value="abc123" />
<nvpair id="Fencing-ipaddr" name="ipaddr" value="192.0.2.1" />
<nvpair id="Fencing-pcmk_host_list" name="pcmk_host_list" value="pcmk-1 pcmk-2" />
</instance_attributes>
<operations >
<op id="Fencing-monitor-10m" interval="10m" name="monitor" timeout="300s" />
</operations>
</primitive>
----
====
Finally, we need to enable STONITH:
----
# crm_attribute -t crm_config -n stonith-enabled -v true
----
== Advanced STONITH Configurations ==
Some people consider that having one fencing device is a single point
of failure footnote:[Not true, since a node or resource must fail
before fencing even has a chance to]; others prefer removing the node
from the storage and network instead of turning it off.
Whatever the reason, Pacemaker supports fencing nodes with multiple
devices through a feature called 'fencing topologies'.
Simply create the individual devices as you normally would, then
define one or more +fencing-level+ entries in the +fencing-topology+ section of
the configuration.
* Each fencing level is attempted in order of ascending +index+. Allowed
values are 1 through 9.
* If a device fails, processing terminates for the current level.
No further devices in that level are exercised, and the next level is attempted instead.
* If the operation succeeds for all the listed devices in a level, the level is deemed to have passed.
* The operation is finished when a level has passed (success), or all levels have been attempted (failed).
* If the operation failed, the next step is determined by the scheduler
and/or the controller.
Some possible uses of topologies include:
* Try poison-pill and fail back to power
* Try disk and network, and fall back to power if either fails
* Initiate a kdump and then poweroff the node
.Properties of Fencing Levels
-[width="95%",cols="1m,3<",options="header",align="center"]
+[width="95%",cols="1m,<3",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the level
indexterm:[id,fencing-level]
indexterm:[Fencing,fencing-level,id]
|target
|The name of a single node to which this level applies
indexterm:[target,fencing-level]
indexterm:[Fencing,fencing-level,target]
|target-pattern
|An extended regular expression (as defined in
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04[POSIX])
matching the names of nodes to which this level applies
indexterm:[target-pattern,fencing-level]
indexterm:[Fencing,fencing-level,target-pattern]
|target-attribute
|The name of a node attribute that is set (to +target-value+) for nodes to
which this level applies
indexterm:[target-attribute,fencing-level]
indexterm:[Fencing,fencing-level,target-attribute]
|target-value
|The node attribute value (of +target-attribute+) that is set for nodes to
which this level applies
indexterm:[target-attribute,fencing-level]
indexterm:[Fencing,fencing-level,target-attribute]
|index
|The order in which to attempt the levels.
Levels are attempted in ascending order 'until one succeeds'.
Valid values are 1 through 9.
indexterm:[index,fencing-level]
indexterm:[Fencing,fencing-level,index]
|devices
|A comma-separated list of devices that must all be tried for this level
indexterm:[devices,fencing-level]
indexterm:[Fencing,fencing-level,devices]
|=========================================================
.Fencing topology with different devices for different nodes
====
[source,XML]
----
<cib crm_feature_set="3.0.6" validate-with="pacemaker-1.2" admin_epoch="1" epoch="0" num_updates="0">
<configuration>
...
<fencing-topology>
<!-- For pcmk-1, try poison-pill and fail back to power -->
<fencing-level id="f-p1.1" target="pcmk-1" index="1" devices="poison-pill"/>
<fencing-level id="f-p1.2" target="pcmk-1" index="2" devices="power"/>
<!-- For pcmk-2, try disk and network, and fail back to power -->
<fencing-level id="f-p2.1" target="pcmk-2" index="1" devices="disk,network"/>
<fencing-level id="f-p2.2" target="pcmk-2" index="2" devices="power"/>
</fencing-topology>
...
<configuration>
<status/>
</cib>
----
====
=== Example Dual-Layer, Dual-Device Fencing Topologies ===
The following example illustrates an advanced use of +fencing-topology+ in a cluster with the following properties:
* 3 nodes (2 active prod-mysql nodes, 1 prod_mysql-rep in standby for quorum purposes)
* the active nodes have an IPMI-controlled power board reached at 192.0.2.1 and 192.0.2.2
* the active nodes also have two independent PSUs (Power Supply Units)
connected to two independent PDUs (Power Distribution Units) reached at
198.51.100.1 (port 10 and port 11) and 203.0.113.1 (port 10 and port 11)
* the first fencing method uses the `fence_ipmi` agent
* the second fencing method uses the `fence_apc_snmp` agent targetting 2 fencing devices (one per PSU, either port 10 or 11)
* fencing is only implemented for the active nodes and has location constraints
* fencing topology is set to try IPMI fencing first then default to a "sure-kill" dual PDU fencing
In a normal failure scenario, STONITH will first select +fence_ipmi+ to try to kill the faulty node.
Using a fencing topology, if that first method fails, STONITH will then move on to selecting +fence_apc_snmp+ twice:
* once for the first PDU
* again for the second PDU
The fence action is considered successful only if both PDUs report the required status. If any of them fails, STONITH loops back to the first fencing method, +fence_ipmi+, and so on until the node is fenced or fencing action is cancelled.
.First fencing method: single IPMI device
Each cluster node has it own dedicated IPMI channel that can be called for fencing using the following primitives:
[source,XML]
----
<primitive class="stonith" id="fence_prod-mysql1_ipmi" type="fence_ipmilan">
<instance_attributes id="fence_prod-mysql1_ipmi-instance_attributes">
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-ipaddr" name="ipaddr" value="192.0.2.1"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-passwd" name="passwd" value="finishme"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-verbose" name="verbose" value="true"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql1"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-lanplus" name="lanplus" value="true"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql2_ipmi" type="fence_ipmilan">
<instance_attributes id="fence_prod-mysql2_ipmi-instance_attributes">
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-ipaddr" name="ipaddr" value="192.0.2.2"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-passwd" name="passwd" value="finishme"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-verbose" name="verbose" value="true"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql2"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-lanplus" name="lanplus" value="true"/>
</instance_attributes>
</primitive>
----
.Second fencing method: dual PDU devices
Each cluster node also has two distinct power channels controlled by two
distinct PDUs. That means a total of 4 fencing devices configured as follows:
- Node 1, PDU 1, PSU 1 @ port 10
- Node 1, PDU 2, PSU 2 @ port 10
- Node 2, PDU 1, PSU 1 @ port 11
- Node 2, PDU 2, PSU 2 @ port 11
The matching fencing agents are configured as follows:
[source,XML]
----
<primitive class="stonith" id="fence_prod-mysql1_apc1" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql1_apc1-instance_attributes">
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-ipaddr" name="ipaddr" value="198.51.100.1"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-port" name="port" value="10"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql1"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql1_apc2" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql1_apc2-instance_attributes">
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-ipaddr" name="ipaddr" value="203.0.113.1"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-port" name="port" value="10"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql1"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql2_apc1" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql2_apc1-instance_attributes">
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-ipaddr" name="ipaddr" value="198.51.100.1"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-port" name="port" value="11"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql2"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql2_apc2" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql2_apc2-instance_attributes">
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-ipaddr" name="ipaddr" value="203.0.113.1"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-port" name="port" value="11"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql2"/>
</instance_attributes>
</primitive>
----
.Location Constraints
To prevent STONITH from trying to run a fencing agent on the same node it is
supposed to fence, constraints are placed on all the fencing primitives:
[source,XML]
----
<constraints>
<rsc_location id="l_fence_prod-mysql1_ipmi" node="prod-mysql1" rsc="fence_prod-mysql1_ipmi" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql2_ipmi" node="prod-mysql2" rsc="fence_prod-mysql2_ipmi" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql1_apc2" node="prod-mysql1" rsc="fence_prod-mysql1_apc2" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql1_apc1" node="prod-mysql1" rsc="fence_prod-mysql1_apc1" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql2_apc1" node="prod-mysql2" rsc="fence_prod-mysql2_apc1" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql2_apc2" node="prod-mysql2" rsc="fence_prod-mysql2_apc2" score="-INFINITY"/>
</constraints>
----
.Fencing topology
Now that all the fencing resources are defined, it's time to create the right topology.
We want to first fence using IPMI and if that does not work, fence both PDUs to effectively and surely kill the node.
[source,XML]
----
<fencing-topology>
<fencing-level devices="fence_prod-mysql1_ipmi" id="fencing-2" index="1" target="prod-mysql1"/>
<fencing-level devices="fence_prod-mysql1_apc1,fence_prod-mysql1_apc2" id="fencing-3" index="2" target="prod-mysql1"/>
<fencing-level devices="fence_prod-mysql2_ipmi" id="fencing-0" index="1" target="prod-mysql2"/>
<fencing-level devices="fence_prod-mysql2_apc1,fence_prod-mysql2_apc2" id="fencing-1" index="2" target="prod-mysql2"/>
</fencing-topology>
----
Please note, in +fencing-topology+, the lowest +index+ value determines the priority of the first fencing method.
.Final configuration
Put together, the configuration looks like this:
[source,XML]
----
<cib admin_epoch="0" crm_feature_set="3.0.7" epoch="292" have-quorum="1" num_updates="29" validate-with="pacemaker-1.2">
<configuration>
<crm_config>
<cluster_property_set id="cib-bootstrap-options">
<nvpair id="cib-bootstrap-options-stonith-enabled" name="stonith-enabled" value="true"/>
<nvpair id="cib-bootstrap-options-stonith-action" name="stonith-action" value="off"/>
<nvpair id="cib-bootstrap-options-expected-quorum-votes" name="expected-quorum-votes" value="3"/>
...
</cluster_property_set>
</crm_config>
<nodes>
<node id="prod-mysql1" uname="prod-mysql1">
<node id="prod-mysql2" uname="prod-mysql2"/>
<node id="prod-mysql-rep1" uname="prod-mysql-rep1"/>
<instance_attributes id="prod-mysql-rep1">
<nvpair id="prod-mysql-rep1-standby" name="standby" value="on"/>
</instance_attributes>
</node>
</nodes>
<resources>
<primitive class="stonith" id="fence_prod-mysql1_ipmi" type="fence_ipmilan">
<instance_attributes id="fence_prod-mysql1_ipmi-instance_attributes">
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-ipaddr" name="ipaddr" value="192.0.2.1"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-passwd" name="passwd" value="finishme"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-verbose" name="verbose" value="true"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql1"/>
<nvpair id="fence_prod-mysql1_ipmi-instance_attributes-lanplus" name="lanplus" value="true"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql2_ipmi" type="fence_ipmilan">
<instance_attributes id="fence_prod-mysql2_ipmi-instance_attributes">
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-ipaddr" name="ipaddr" value="192.0.2.2"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-passwd" name="passwd" value="finishme"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-verbose" name="verbose" value="true"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql2"/>
<nvpair id="fence_prod-mysql2_ipmi-instance_attributes-lanplus" name="lanplus" value="true"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql1_apc1" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql1_apc1-instance_attributes">
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-ipaddr" name="ipaddr" value="198.51.100.1"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-port" name="port" value="10"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc1-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql1"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql1_apc2" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql1_apc2-instance_attributes">
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-ipaddr" name="ipaddr" value="203.0.113.1"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-port" name="port" value="10"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql1_apc2-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql1"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql2_apc1" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql2_apc1-instance_attributes">
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-ipaddr" name="ipaddr" value="198.51.100.1"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-port" name="port" value="11"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc1-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql2"/>
</instance_attributes>
</primitive>
<primitive class="stonith" id="fence_prod-mysql2_apc2" type="fence_apc_snmp">
<instance_attributes id="fence_prod-mysql2_apc2-instance_attributes">
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-ipaddr" name="ipaddr" value="203.0.113.1"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-action" name="action" value="off"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-port" name="port" value="11"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-login" name="login" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-passwd" name="passwd" value="fencing"/>
<nvpair id="fence_prod-mysql2_apc2-instance_attributes-pcmk_host_list" name="pcmk_host_list" value="prod-mysql2"/>
</instance_attributes>
</primitive>
</resources>
<constraints>
<rsc_location id="l_fence_prod-mysql1_ipmi" node="prod-mysql1" rsc="fence_prod-mysql1_ipmi" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql2_ipmi" node="prod-mysql2" rsc="fence_prod-mysql2_ipmi" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql1_apc2" node="prod-mysql1" rsc="fence_prod-mysql1_apc2" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql1_apc1" node="prod-mysql1" rsc="fence_prod-mysql1_apc1" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql2_apc1" node="prod-mysql2" rsc="fence_prod-mysql2_apc1" score="-INFINITY"/>
<rsc_location id="l_fence_prod-mysql2_apc2" node="prod-mysql2" rsc="fence_prod-mysql2_apc2" score="-INFINITY"/>
</constraints>
<fencing-topology>
<fencing-level devices="fence_prod-mysql1_ipmi" id="fencing-2" index="1" target="prod-mysql1"/>
<fencing-level devices="fence_prod-mysql1_apc1,fence_prod-mysql1_apc2" id="fencing-3" index="2" target="prod-mysql1"/>
<fencing-level devices="fence_prod-mysql2_ipmi" id="fencing-0" index="1" target="prod-mysql2"/>
<fencing-level devices="fence_prod-mysql2_apc1,fence_prod-mysql2_apc2" id="fencing-1" index="2" target="prod-mysql2"/>
</fencing-topology>
...
</configuration>
</cib>
----
== Remapping Reboots ==
When the cluster needs to reboot a node, whether because +stonith-action+ is +reboot+ or because
a reboot was manually requested (such as by `stonith_admin --reboot`), it will remap that to
other commands in two cases:
. If the chosen fencing device does not support the +reboot+ command, the cluster
will ask it to perform +off+ instead.
. If a fencing topology level with multiple devices must be executed, the cluster
will ask all the devices to perform +off+, then ask the devices to perform +on+.
To understand the second case, consider the example of a node with redundant
power supplies connected to intelligent power switches. Rebooting one switch
and then the other would have no effect on the node. Turning both switches off,
and then on, actually reboots the node.
In such a case, the fencing operation will be treated as successful as long as
the +off+ commands succeed, because then it is safe for the cluster to recover
any resources that were on the node. Timeouts and errors in the +on+ phase will
be logged but ignored.
When a reboot operation is remapped, any action-specific timeout for the
remapped action will be used (for example, +pcmk_off_timeout+ will be used when
executing the +off+ command, not +pcmk_reboot_timeout+).
diff --git a/doc/Pacemaker_Remote/en-US/Ch-Options.txt b/doc/Pacemaker_Remote/en-US/Ch-Options.txt
index 87663f8727..f50cd25f7c 100644
--- a/doc/Pacemaker_Remote/en-US/Ch-Options.txt
+++ b/doc/Pacemaker_Remote/en-US/Ch-Options.txt
@@ -1,136 +1,136 @@
= Configuration Explained =
The walk-through examples use some of these options, but don't explain exactly
what they mean or do. This section is meant to be the go-to resource for all
the options available for configuring pacemaker_remote-based nodes.
(((configuration)))
== Resource Meta-Attributes for Guest Nodes ==
When configuring a virtual machine as a guest node, the virtual machine is
created using one of the usual resource agents for that purpose (for example,
ocf:heartbeat:VirtualDomain or ocf:heartbeat:Xen), with additional metadata
parameters.
No restrictions are enforced on what agents may be used to create a guest node,
but obviously the agent must create a distinct environment capable of running
the pacemaker_remote daemon and cluster resources. An additional requirement is
that fencing the host running the guest node resource must be sufficient for
ensuring the guest node is stopped. This means, for example, that not all
hypervisors supported by VirtualDomain may be used to create guest nodes; if
the guest can survive the hypervisor being fenced, it may not be used as a
guest node.
Below are the metadata options available to enable a resource as a guest node
and define its connection parameters.
.Meta-attributes for configuring VM resources as guest nodes
-[width="95%",cols="2m,1,4<",options="header",align="center"]
+[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Option
|Default
|Description
|remote-node
|'none'
|The node name of the guest node this resource defines. This both enables the
resource as a guest node and defines the unique name used to identify the
guest node. If no other parameters are set, this value will also be assumed as
the hostname to use when connecting to pacemaker_remote on the VM. This value
*must not* overlap with any resource or node IDs.
|remote-port
|3121
|The port on the virtual machine that the cluster will use to connect to
pacemaker_remote.
|remote-addr
|'value of' +remote-node+
|The IP address or hostname to use when connecting to pacemaker_remote on the VM.
|remote-connect-timeout
|60s
|How long before a pending guest connection will time out.
|=========================================================
== Connection Resources for Remote Nodes ==
A remote node is defined by a connection resource. That connection resource
has instance attributes that define where the remote node is located on the
network and how to communicate with it.
Descriptions of these instance attributes can be retrieved using the following
`pcs` command:
----
# pcs resource describe remote
ocf:pacemaker:remote - remote resource agent
Resource options:
server: Server location to connect to. This can be an ip address or hostname.
port: tcp port to connect to.
reconnect_interval: Interval in seconds at which Pacemaker will attempt to
reconnect to a remote node after an active connection to
the remote node has been severed. When this value is
nonzero, Pacemaker will retry the connection
indefinitely, at the specified interval. As with any
time-based actions, this is not guaranteed to be checked
more frequently than the value of the
cluster-recheck-interval cluster option.
----
When defining a remote node's connection resource, it is common and recommended
to name the connection resource the same as the remote node's hostname. By
default, if no *server* option is provided, the cluster will attempt to contact
the remote node using the resource name as the hostname.
Example defining a remote node with the hostname *remote1*:
----
# pcs resource create remote1 remote
----
Example defining a remote node to connect to a specific IP address and port:
----
# pcs resource create remote1 remote server=192.168.122.200 port=8938
----
== Environment Variables for Daemon Start-up ==
Authentication and encryption of the connection between cluster nodes
and nodes running pacemaker_remote is achieved using
with https://en.wikipedia.org/wiki/TLS-PSK[TLS-PSK] encryption/authentication
over TCP (port 3121 by default). This means that both the cluster node and
remote node must share the same private key. By default, this
key is placed at +/etc/pacemaker/authkey+ on each node.
You can change the default port and/or key location for Pacemaker and
pacemaker_remote via environment variables. How these variables are set varies
by OS, but usually they are set in the +/etc/sysconfig/pacemaker+ or
+/etc/default/pacemaker+ file.
----
#==#==# Pacemaker Remote
# Use a custom directory for finding the authkey.
PCMK_authkey_location=/etc/pacemaker/authkey
#
# Specify a custom port for Pacemaker Remote connections
PCMK_remote_port=3121
----
== Removing Remote Nodes and Guest Nodes ==
If the resource creating a guest node, or the *ocf:pacemaker:remote* resource
creating a connection to a remote node, is removed from the configuration, the
affected node will continue to show up in output as an offline node.
If you want to get rid of that output, run (replacing $NODE_NAME appropriately):
----
# crm_node --force --remove $NODE_NAME
----
[WARNING]
=========
Be absolutely sure that there are no references to the node's resource in the
configuration before running the above command.
=========
diff --git a/doc/asciidoc.reference b/doc/asciidoc.reference
index 9323864998..e06d96c251 100644
--- a/doc/asciidoc.reference
+++ b/doc/asciidoc.reference
@@ -1,70 +1,96 @@
= Single-chapter part of the documentation =
== Go-to reference chapter for how we use AsciiDoc on this project ==
[NOTE]
======
This is *not* an attempt for fully self-hosted AsciiDoc document,
consider it a plaintext full of AsciiDoc samples (it's up to the reader
to recognize the borderline) at documentation writers' disposal
to somewhat standardize the style{empty}footnote:[
style of both source notation and final visual appearance
].
See also:
http://powerman.name/doc/asciidoc
======
Emphasis: _some test_
Mono: +some text+
Strong: *some text*
Super: ^some text^
Sub: ~some text~
Quotes:
``double quoted''
`single quoted'
Command: `some-tool --with option`
Newly introduced term:
'some text' (another form of emphasis as of this edit)
File: mono
Literal: mono
Tool: command
Option: mono
Replaceable: emphasis mono
Varname: mono
Term encountered on system (e.g., menu choice, hostname):
strong
.Title for Example
=====
Some text
=====
.Title for Example with XML Listing
=====
[source,XML]
-----
<some xml=here/>
-----
=====
Naked code listing:
(Use 'C' and a leading '#' instead of 'Bash' when commands are being show)
[source,C]
-----
# some command --here
-----
Section anchors:
[[s-name]]
=== Some Section Title ===
References to section anchors:
<<s-name>> or <<s-name,Alternate Text>>
+
+
+Tables:
+
+Typically styled like this:
+[width="95%",cols="1m,<4m,<6",options="header",align="center"]
+
+It's vital that column alignment/style, if any, goes first/last in the proper
+column specifier (as a whole possibly preceded with column multiplier),
+otherwise Asciidoctor will end up with invalid DocBook sources:
+- correct: 1m,<4m,<6
+- bad: 1m,4<m,6<
+
+Avoid "a" (asciidoc) style for the columns, since it will prevent any
+reference anchors being placed there. However, if the particular cell
+is to carry a list (inherently a block element) or a comment that should
+be omitted from the output, it needs to be turned into asciidoc style like
+this (note the initial 'a'):
+
+|col1-per-row
+|col2-per-row
+|Details for col1 + col2 per row combo:
+a|Hence either:
+
+* foo
+* bar

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