diff --git a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
index 9b8945d7ed..a8e38f214e 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
@@ -1,761 +1,757 @@
:compat-mode: legacy
= 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]
=====
[[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:[N]+ 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 <> 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`.
A cluster node in standby mode will not run resources, but still contributes to
quorum, and may fence or be fenced by nodes.
==== 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]
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]
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 <>. 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"]
|=========================================================
|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]
------------
------------
=====
[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
<>.
======
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]
-------
-------
=====
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]
-------
...
...
...
-------
=====
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]
-------
-------
=====
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]
-------
-------
=====
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]
-------
-------
=====
[[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"]
|=========================================================
|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"]
|=========================================================
|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 <>) 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).
In order to take advantage of this feature - firstly add the resource to your cluster, preferably as a cloned resource to constantly measure health on all nodes:
=====
[source,XML]
------------
------------
=====
This way attrd_updater will set proper status for each node running this resource. Any attribute matching "#health-[a-zA-z]+" will force cluster to migrate all resources from unhealthy node and place it on other nodes according to all constraints defined in your cluster.
When the node is no longer faulty you can force the cluster to restart the cloned resource on faulty node and make it available to take resources, in this case since we are using HealthIOWait provider:
----
# attrd_updater -n "#health-iowait" -U "green" --node="" -d "60s"
----
== 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]
-------
1.1
Master/Slave OCF Resource Agent for DRBD
...
-------
=====
. 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]
-------
Full path to the drbd.conf file.
Path to drbd.conf
-------
=====
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-Options.txt b/doc/Pacemaker_Explained/en-US/Ch-Options.txt
index e058d91675..f864987010 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Options.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Options.txt
@@ -1,439 +1,438 @@
:compat-mode: legacy
= 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]
-------
-------
======
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"]
|=========================================================
|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 <> 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",options="header",align="center"]
|=========================================================
|Option |Default |Description
| cluster-name | |
indexterm:[cluster-name,Cluster Property]
indexterm:[Cluster,Property,cluster-name]
An (optional) name for the cluster as a whole. This is mostly for users'
convenience for use as desired in administration, but this can be used
in the Pacemaker configuration in <> (as the
+#cluster-name+ <>). It may
also be used by higher-level tools when displaying cluster information, and by
certain resource agents (for example, the +ocf:heartbeat:GFS2+ agent stores the
cluster name in filesystem meta-data).
| 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
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 <> actions that the cluster
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 <>).
| 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 <>.
| 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?
| fence-reaction | stop |
indexterm:[fence-reaction,Cluster Option]
indexterm:[Cluster,Option,fence-reaction]
How should a cluster node react if notified of its own fencing? A cluster node
may receive notification of its own fencing if fencing is misconfigured, or if
fabric fencing is in use that doesn't cut cluster communication. Allowed values
are +stop+ to attempt to immediately stop pacemaker and stay stopped, or
+panic+ to attempt to immediately reboot the local node, falling back to stop
on failure. The default is likely to be changed to +panic+ in a future release.
'(since 2.0.3)'
| 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 DC 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 <>).
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 <>).
Allowed values are +none+, +migrate-on-red+, +only-green+, +progressive+, and
+custom+.
| enable-acl | FALSE |
indexterm:[enable-acl,Cluster Option]
indexterm:[Cluster,Option,enable-acl]
Whether access control lists (ACLs) (see <>) can be used to authorize
modifications to the CIB.
| 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+.
+| cluster-recheck-interval | 15min |
+indexterm:[cluster-recheck-interval,Cluster Option]
+indexterm:[Cluster,Option,cluster-recheck-interval]
+Pacemaker is primarily event-driven, and looks ahead to know when to recheck
+the cluster for failure timeouts and most time-based rules. However, it will
+also recheck the cluster after this amount of inactivity. This has two goals:
+rules with +date_spec+ are only guaranteed to be checked this often, and it
+also serves as a fail-safe for certain classes of scheduler bugs. A value of 0
+disables this polling; positive values are a time interval.
+
| 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 f5c873ad9d..d8e7115dbd 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
@@ -1,910 +1,907 @@
:compat-mode: legacy
= 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 https://github.com/ClusterLabs/OCF-spec/tree/master/ra . The
Pacemaker implementation has been somewhat extended from the OCF specs.]
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 more commonly known as 'init scripts'. If a full path
is not given, they are assumed to be located in +/etc/init.d+.
Commonly, they are provided by the OS distribution. In order to be used
with a Pacemaker cluster, they must conform to the LSB specification.
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
====
[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 <>.
=== 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"]
|=========================================================
|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]
=====
[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]
-------
-------
=====
[[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",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
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
<>, promoted to master if
appropriate)
* +Slave:+ Allow the resource to be started, but only in Slave mode if
the resource is <>
* +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]
|maintenance
|FALSE
|Similar to the +maintenance-mode+ <>, but for
a single resource. If true, the resource will not be started, stopped, or
monitored on any node. This differs from +is-managed+ in that monitors will
not be run. Allowed values: +true+, +false+
indexterm:[maintenance,Resource Option]
indexterm:[Resource,Option,maintenance]
|resource-stickiness
|1 for individual clone instances, 0 for all other resources
|A score that will be added to the current node when a resource is already
active. This allows running resources to stay where they are, even if
they would be placed elsewhere if they were being started from a stopped
state.
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+
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 <>
* +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
<>
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
- <>).
indexterm:[failure-timeout,Resource Option]
indexterm:[Resource,Option,failure-timeout]
|multiple-active
|stop_start
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 <>)
|container-attribute-target
|
|Specific to bundle resources; see <>
|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]
-------
-------
=====
In addition to the cluster-defined meta-attributes described above, you may
also configure arbitrary meta-attributes of your own choosing. Most commonly,
this would be done for use in <>. For example, an IT department
might define a custom meta-attribute to indicate which company department each
resource is intended for. To reduce the chance of name collisions with
cluster-defined meta-attributes added in the future, it is recommended to use
a unique, organization-specific prefix for such attributes.
[[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]
-------
-------
=====
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]
-------
1.0
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.
Example stateless resource agent
Location to store the resource state in.
State file
Fake attribute that can be changed to cause a reload
Fake attribute that can be changed to cause a reload
Number of seconds to sleep during operations. This can be used to test how
the cluster reacts to operation timeouts.
Operation sleep duration in seconds.
-------
=====
== 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.
Operations may be explicitly configured for two purposes: to override defaults
for options (such as timeout) that the cluster will use whenever it initiates
the operation, and to run an operation on a recurring basis (for example, to
monitor the resource for failure).
.An OCF resource with a non-default start timeout
=====
[source,XML]
-------
-------
=====
Pacemaker identifies operations by a combination of name and interval, so this
combination must be unique for each resource. That is, you should not configure
two operations for the same resource with the same name and interval.
[[s-operation-properties]]
=== Operation Properties ===
Operation properties may be specified directly in the +op+ element as
XML attributes, or in a separate +meta_attributes+ block as +nvpair+ elements.
XML attributes take precedence over +nvpair+ elements if both are specified.
.Properties of an Operation
[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 "when
needed". A positive value defines a 'recurring action', which is typically
used with <>.
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)'
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 <>.
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
|TRUE
|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 <>).
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 <>, +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.
footnote:[Currently, anyway. Automatic monitoring operations may be
added in a future version of Pacemaker.]
You must configure +monitor+ operations explicitly to perform these checks.
.An OCF resource with a recurring health check
=====
[source,XML]
-------
-------
=====
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).
[NOTE]
====
Currently, monitors with +role=Stopped+ are not implemented for
<> resources.
====
[[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+ (which will be newly initiated 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
specifying +role+ as +Stopped+ (which will be newly initiated if
appropriate). 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]
-------
-------
=====
=== 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]
-------
-------
=====
=== 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]
-------
-------
=====
This can be achieved from the command line by executing:
----
# cibadmin --modify --xml-text ''
----
Once you've done whatever you needed to do, you can then re-enable it with
----
# cibadmin --modify --xml-text ''
----
diff --git a/doc/Pacemaker_Explained/en-US/Ch-Rules.txt b/doc/Pacemaker_Explained/en-US/Ch-Rules.txt
index a2f8b87cef..9d617f601c 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Rules.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Rules.txt
@@ -1,757 +1,754 @@
:compat-mode: legacy
= 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:[Constraint,Rule]
Rules can be used to make your configuration more dynamic, allowing values to
change depending on the time or the value of a node attribute. Examples of
things rules are useful for:
* Set a higher value for <> during
working hours, to minimize downtime, and a lower value on weekends, to allow
resources to move to their most preferred locations when people aren't around
to notice.
* Automatically place the cluster into maintenance mode during a scheduled
maintenance window.
* Assign certain nodes and resources to a particular department via custom
node attributes and meta-attributes, and add a single location constraint
that restricts the department's resources to run only on those nodes.
Each constraint type or property set that supports rules may contain one or more
+rule+ elements specifying conditions under which the constraint or properties
take effect. Examples later in this chapter will make this clearer.
== Rule Properties ==
indexterm:[XML element,rule element]
.Attributes of a rule Element
[width="95%",cols="2m,1,<5",options="header",align="center"]
|=========================================================
|Attribute
|Default
|Description
|id
|
|A unique name for the rule (required)
indexterm:[XML attribute,id attribute,rule element]
indexterm:[XML element,rule element,id attribute]
|role
|+Started+
|The rule is in effect 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:[XML attribute,role attribute,rule element]
indexterm:[XML element,rule element,role attribute]
|score
|
|If this rule is used in a location constraint and evaluates to true, apply
this score to the constraint. Only one of +score+ and +score-attribute+ may be
used.
indexterm:[XML attribute,score attribute,rule element]
indexterm:[XML element,rule element,score attribute]
|score-attribute
|
|If this rule is used in a location constraint and evaluates to true, use the
value of this node attribute as the score to apply to the constraint. Only one
of +score+ and +score-attribute+ may be used.
indexterm:[XML attribute,score-attribute attribute,rule element]
indexterm:[XML element,rule element,score-attribute attribute]
|boolean-op
|+and+
|If this rule contains more than one condition, a value of +and+ specifies that
the rule evaluates to true only if all conditions are true, and a value of
+or+ specifies that the rule evaluates to true if any condition is true.
indexterm:[XML attribute,boolean-op attribute,rule element]
indexterm:[XML element,rule element,boolean-op attribute]
|=========================================================
A +rule+ element must contain one or more conditions. A condition may be an
+expression+ element, a +date_expression+ element, or another +rule+ element.
== Node Attribute Expressions ==
[[node-attribute-expressions]]
indexterm:[Rule,Node Attribute Expression]
indexterm:[XML element,expression element]
Expressions are rule conditions based on the values of node attributes.
.Attributes of an expression Element
[width="95%",cols="2m,1,<5",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|id
|
|A unique name for the expression (required)
indexterm:[XML attribute,id attribute,expression element]
indexterm:[XML element,expression element,id attribute]
|attribute
|
|The node attribute to test (required)
indexterm:[XML attribute,attribute attribute,expression element]
indexterm:[XML element,expression element,attribute attribute]
|type
|+string+
|How the node attributes should be compared. Allowed values are
+string+, +integer+, and +version+.
indexterm:[XML attribute,type attribute,expression element]
indexterm:[XML element,expression element,type attribute]
|operation
|
a|The comparison to perform (required). Allowed values:
* +lt:+ True if the node attribute value is less than the comparison value
* +gt:+ True if the node attribute value is greater than the comparison value
* +lte:+ True if the node attribute value is less than or equal to the comparison value
* +gte:+ True if the node attribute value is greater than or equal to the comparison value
* +eq:+ True if the node attribute value is equal to the comparison value
* +ne:+ True if the node attribute value is not equal to the comparison value
* +defined:+ True if the node has the named attribute
* +not_defined:+ True if the node does not have the named attribute
indexterm:[XML attribute,operation attribute,expression element]
indexterm:[XML element,expression element,operation attribute]
|value
|
|User-supplied value for comparison (required for operations other than
+defined+ and +not_defined+)
indexterm:[XML attribute,value attribute,expression element]
indexterm:[XML element,expression element,value attribute]
|value-source
|+literal+
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:[XML attribute,value-source attribute,expression element]
indexterm:[XML element,expression element,value-source attribute]
|=========================================================
[[node-attribute-expressions-special]]
In addition to custom node attributes defined by the administrator, the cluster
defines special, built-in node attributes for each node that can also be used
in rule expressions.
.Built-in Node Attributes
[width="95%",cols="1m,<5",options="header",align="center"]
|=========================================================
|Name
|Value
|#uname
|Node <>
|#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+ node attribute, if set, otherwise identical to
+#cluster-name+
|#role
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)'
////
|=========================================================
== Date/Time Expressions ==
indexterm:[Rule,Date/Time Expression]
indexterm:[XML element,date_expression element]
Date/time expressions are rule conditions based (as the name suggests) on the
current date and time.
A +date_expression+ element may optionally contain a +date_spec+ or +duration+
element depending on the context.
.Attributes of a date_expression Element
[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the expression (required)
indexterm:[XML attribute,id attribute,date_expression element]
indexterm:[XML element,date_expression element,id attribute]
|start
|A date/time conforming to the http://en.wikipedia.org/wiki/ISO_8601[ISO8601]
specification. May be used when +operation+ is +in_range+ (in which case at
least one of +start+ or +end+ must be specified) or +gt+ (in which case
+start+ is required).
indexterm:[XML attribute,start attribute,date_expression element]
indexterm:[XML element,date_expression element,start attribute]
|end
|A date/time conforming to the http://en.wikipedia.org/wiki/ISO_8601[ISO8601]
specification. May be used when +operation+ is +in_range+ (in which case at
least one of +start+ or +end+ must be specified) or +lt+ (in which case
+end+ is required).
indexterm:[XML attribute,end attribute,date_expression element]
indexterm:[XML element,date_expression element,end attribute]
|operation
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+ (if specified)
and before either +end+ (if specified) or +start+ plus the value of the
+duration+ element (if one is contained in the +date_expression+)
* +date_spec:+ True if the current date/time matches the specification
given in the contained +date_spec+ element (described below)
indexterm:[XML attribute,operation attribute,date_expression element]
indexterm:[XML element,date_expression element,operation attribute]
|=========================================================
[NOTE]
======
There is no +eq+, +neq+, +gte+, or +lte+ operation, since they would be valid
only for a single second.
======
=== Date Specifications ===
indexterm:[Rule,Date/Time Expression,Date Specification]
indexterm:[XML element,date_spec element]
A +date_spec+ element is used to create a cron-like expression relating
to time. Each field can contain a single number or range. Any field not
supplied is ignored.
.Attributes of a date_spec Element
[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the object (required)
indexterm:[XML attribute,id attribute,date_spec element]
indexterm:[XML element,date_spec element,id attribute]
|hours
|Allowed values: 0-23 (where 0 is midnight and 23 is 11 p.m.)
indexterm:[XML attribute,hours attribute,date_spec element]
indexterm:[XML element,date_spec element,hours attribute]
|monthdays
|Allowed values: 1-31 (depending on month and year)
indexterm:[XML attribute,monthdays attribute,date_spec element]
indexterm:[XML element,date_spec element,monthdays attribute]
|weekdays
|Allowed values: 1-7 (where 1 is Monday and 7 is Sunday)
indexterm:[XML attribute,weekdays attribute,date_spec element]
indexterm:[XML element,date_spec element,weekdays attribute]
|yeardays
|Allowed values: 1-366 (depending on the year)
indexterm:[XML attribute,yeardays attribute,date_spec element]
indexterm:[XML element,date_spec element,yeardays attribute]
|months
|Allowed values: 1-12
indexterm:[XML attribute,months attribute,date_spec element]
indexterm:[XML element,date_spec element,months attribute]
|weeks
|Allowed values: 1-53 (depending on weekyear)
indexterm:[XML attribute,weeks attribute,date_spec element]
indexterm:[XML element,date_spec element,weeks attribute]
|years
|Year according to the Gregorian calendar
indexterm:[XML attribute,years attribute,date_spec element]
indexterm:[XML element,date_spec element,years attribute]
|weekyears
|Year in which the week started; for example, 1 January 2005 can be specified
in ISO 8601 as '2005-001 Ordinal', '2005-01-01 Gregorian' or
'2004-W53-6 Weekly' and thus would match +years="2005"+ or +weekyears="2004"+
indexterm:[XML attribute,weekyears attribute,date_spec element]
indexterm:[XML element,date_spec element,weekyears attribute]
|moon
|Allowed values are 0-7 (where 0 is the new moon and 4 is full moon).
Seriously, you can use this. This was implemented to demonstrate the ease with
which new comparisons could be added.
indexterm:[XML attribute,moon attribute,date_spec element]
indexterm:[XML element,date_spec element,moon attribute]
|=========================================================
For example, +monthdays="1"+ matches the first day of every month, and
+hours="09-17"+ matches the hours between 9 a.m. and 5 p.m. (inclusive).
At this time, multiple ranges (e.g. +weekdays="1,2"+ or +weekdays="1-2,5-6"+)
are not supported.
+[NOTE]
+====
+Pacemaker can calculate when evaluation of a +date_expression+ with an
++operation+ of +gt+, +lt+, or +in_range+ will next change, and schedule a
+cluster re-check for that time. However, it does not do this for +date_spec+.
+Instead, it evaluates the +date_spec+ whenever a cluster re-check naturally
+happens via a cluster event or the +cluster-recheck-interval+ cluster option.
+For example, if you have a +date_spec+ enabling a resource from 9 a.m. to 5 p.m.,
+and +cluster-recheck-interval+ has been set to 5 minutes, then sometime between
+9 a.m. and 9:05 a.m. the cluster would notice that it needs to start the
+resource, and sometime between 5 p.m. and 5:05 p.m. it would realize that it
+needs to stop the resource. The timing of the actual start and stop actions
+will further depend on factors such as any other actions the cluster may need
+to perform first, and the load of the machine.
+====
+
=== Durations ===
indexterm:[Rule,Date/Time Expression,Duration]
indexterm:[XML element,duration element]
A +duration+ is used to calculate a value for +end+ when one is not supplied to
+in_range+ operations. It contains one or more attributes each containing a
single number. Any attribute not supplied is ignored.
.Attributes of a duration Element
[width="95%",cols="2m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for this duration element (required)
indexterm:[XML attribute,id attribute,duration element]
indexterm:[XML element,duration element,id attribute]
|seconds
|This many seconds will be added to the total duration
indexterm:[XML attribute,seconds attribute,duration element]
indexterm:[XML element,duration element,seconds attribute]
|minutes
|This many minutes will be added to the total duration
indexterm:[XML attribute,minutes attribute,duration element]
indexterm:[XML element,duration element,minutes attribute]
|hours
|This many hours will be added to the total duration
indexterm:[XML attribute,hours attribute,duration element]
indexterm:[XML element,duration element,hours attribute]
|weeks
|This many weeks will be added to the total duration
indexterm:[XML attribute,weeks attribute,duration element]
indexterm:[XML element,duration element,weeks attribute]
|months
|This many months will be added to the total duration
indexterm:[XML attribute,months attribute,duration element]
indexterm:[XML element,duration element,months attribute]
|years
|This many years will be added to the total duration
indexterm:[XML attribute,years attribute,duration element]
indexterm:[XML element,duration element,years attribute]
|=========================================================
=== Example Time-Based Expressions ===
A small sample of how time-based expressions can be used:
.True if now is any time in the year 2005
====
[source,XML]
----
----
====
.Equivalent expression
====
[source,XML]
----
----
====
.9am-5pm Monday-Friday
====
[source,XML]
-------
-------
====
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]
-------
-------
====
.9am-5pm or 9pm-12am Monday through Friday
====
[source,XML]
-------
-------
====
.Mondays in March 2005
====
[source,XML]
-------
-------
====
[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]
-------
-------
=====
-[[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.
-
== Using Rules to Determine Resource Location ==
indexterm:[Rule,Determine Resource Location]
indexterm:[Resource,Location,Determine by Rules]
A location constraint may contain one or more top-level rules. The cluster
will act as if there is a separate location constraint for each rule that
evaluates as true.
Consider the following simple location constraint:
.Prevent resource "webserver" from running on node3
=====
[source,XML]
-------
-------
=====
The constraint can be more verbosely written using a rule:
.Prevent resource "webserver" from running on node3 using rule
=====
[source,XML]
-------
-------
=====
The advantage of using the expanded form is that one could add more expressions
(for example, limiting the constraint to certain days of the week), or activate
the constraint by some node attribute other than node name.
=== 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]
-------
-------
=====
then we could prevent resources from running on underpowered machines with this rule:
[source,XML]
-------
-------
=== 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 Define Options ==
Rules may be used to control a variety of options:
* <> (+cluster_property_set+ elements)
* <> (as +instance_attributes+ or
+utilization+ elements inside a +node+ element)
* <> (as +utilization+, +meta_attributes+,
or +instance_attributes+ elements inside a resource definition element or
+op+ , +rsc_defaults+, +op_defaults+, or +template+ element)
* <> (+meta_attributes+
inside an +op+ or +op_defaults+ element)
=== 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]
-------
-------
=====
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 Resource Defaults ===
Rules can be used for resource and operation defaults. 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]
-------
-------
=====
Rules may be used similarly in +instance_attributes+ or +utilization+ blocks.
Any single block may directly contain only a single rule, but that rule may
itself contain any number of rules.
=== 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 +maintenance_mode+ during a scheduled
maintenance window. This will keep the cluster running but not monitor, start,
or stop resources during this time.
.Schedule a maintenance window for 9 to 11 p.m. CDT Sept. 20, 2019
=====
[source,XML]
-------
-------
=====
[IMPORTANT]
====
The +cluster_property_set+ with an +id+ set to "cib-bootstrap-options" will
'always' have the highest priority, regardless of any scores. Therefore,
rules in another +cluster_property_set+ can never take effect for any
properties listed in the bootstrap set.
====
diff --git a/doc/Pacemaker_Remote/en-US/Ch-Options.txt b/doc/Pacemaker_Remote/en-US/Ch-Options.txt
index f238e0da1b..288bc9f27d 100644
--- a/doc/Pacemaker_Remote/en-US/Ch-Options.txt
+++ b/doc/Pacemaker_Remote/en-US/Ch-Options.txt
@@ -1,137 +1,134 @@
:compat-mode: legacy
= 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"]
|=========================================================
|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.
+ indefinitely, at the specified interval.
----
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.
=========