diff --git a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
index 890bc13490..945a53c2b1 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Options.txt
@@ -1,715 +1,716 @@
= Advanced Configuration =
[[s-remote-connection]]
== Connecting from a Remote Machine ==
indexterm:[Cluster,Remote connection]
indexterm:[Cluster,Remote administration]
Provided Pacemaker is installed on a machine, it is possible to
connect to the cluster even if the machine itself is not in the same
cluster. To do this, one simply sets up a number of environment
variables and runs the same commands as when working on a cluster
node.
.Environment Variables Used to Connect to Remote Instances of the CIB
[width="95%",cols="1m,1,3<",options="header",align="center"]
|=========================================================
|Environment Variable
|Default
|Description
|CIB_user
|$USER
|The user to connect as. Needs to be part of the +hacluster+ group on
the target host.
indexterm:[Environment Variable,CIB_user]
|CIB_passwd
|
|The user's password. Read from the command line if unset.
indexterm:[Environment Variable,CIB_passwd]
|CIB_server
|localhost
|The host to contact
indexterm:[Environment Variable,CIB_server]
|CIB_port
|
|The port on which to contact the server; required.
indexterm:[Environment Variable,CIB_port]
|CIB_encrypted
|TRUE
|Whether to encrypt network traffic
indexterm:[Environment Variable,CIB_encrypted]
|=========================================================
So, if *c001n01* is an active cluster node and is listening on port 1234
for connections, and *someuser* is a member of the *hacluster* group,
then the following would prompt for *someuser*'s password and return
the cluster's current configuration:
----
# export CIB_port=1234; export CIB_server=c001n01; export CIB_user=someuser;
# cibadmin -Q
----
For security reasons, the cluster does not listen for remote
connections by default. If you wish to allow remote access, you need
to set the +remote-tls-port+ (encrypted) or +remote-clear-port+
(unencrypted) CIB properties (i.e., those kept in the +cib+ tag, like
+num_updates+ and +epoch+).
.Extra top-level CIB properties for remote access
[width="95%",cols="1m,1,3<",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|remote-tls-port
|_none_
|Listen for encrypted remote connections on this port.
indexterm:[remote-tls-port,Remote Connection Option]
indexterm:[Remote Connection,Option,remote-tls-port]
|remote-clear-port
|_none_
|Listen for plaintext remote connections on this port.
indexterm:[remote-clear-port,Remote Connection Option]
indexterm:[Remote Connection,Option,remote-clear-port]
|=========================================================
[[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]
=====
== Moving Resources ==
indexterm:[Moving,Resources]
indexterm:[Resource,Moving]
=== Moving Resources Manually ===
There are primarily two occasions when you would want to move a
resource from its current location: when the whole node is under
maintenance, and when a single resource needs to be moved.
==== Standby Mode ====
Since everything eventually comes down to a score, you could create
constraints for every resource to prevent them from running on one
node. While pacemaker configuration can seem convoluted at times, not even
we would require this of administrators.
Instead, one can set a special node attribute which tells the cluster
"don't let anything run here". There is even a helpful tool to help
query and set it, called `crm_standby`. To check the standby status
of the current machine, run:
----
# crm_standby -G
----
A value of +on+ indicates that the node is _not_ able to host any
resources, while a value of +off+ says that it _can_.
You can also check the status of other nodes in the cluster by
specifying the `--node` option:
----
# crm_standby -G --node sles-2
----
To change the current node's standby status, use `-v` instead of `-G`:
----
# crm_standby -v on
----
Again, you can change another host's value by supplying a hostname with `--node`.
==== Moving One Resource ====
When only one resource is required to move, we could do this by creating
location constraints. However, once again we provide a user-friendly
shortcut as part of the `crm_resource` command, which creates and
modifies the extra constraints for you. If +Email+ were running on
+sles-1+ and you wanted it moved to a specific location, the command
would look something like:
----
# crm_resource -M -r Email -H sles-2
----
Behind the scenes, the tool will create the following location constraint:
[source,XML]
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.
[[s-failure-migration]]
=== Moving Resources Due to Failure ===
Normally, if a running resource fails, pacemaker will try to start
it again on the same node. 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.
indexterm:[migration-threshold]
indexterm:[failure-timeout]
indexterm:[start-failure-is-fatal]
Pacemaker allows you to set your preference via the +migration-threshold+
resource option.
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.
]
Simply define +migration-threshold=pass:[N]+ for a resource and it will
migrate to a new node after 'N' failures. There is no threshold defined
by default. To determine the resource's current failure status and
limits, run `crm_mon --failcounts`.
By default, once the threshold has been reached, the troublesome node will no
longer be allowed to run the failed resource until the administrator
manually resets the resource's failcount using `crm_failcount` (after
hopefully first fixing the failure's cause). Alternatively, it is possible
to expire them by setting the +failure-timeout+ option for the resource.
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.
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 failcount 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 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 Heartbeat required users to add ping nodes to +ha.cf+, but
this is no longer required.
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 Policy Engine is not yet able to model this
situation correctly and so takes the safer (if less optimal) path.
In pacemaker 1.1.11 and earlier, a migratable resource will be restarted
when moving if it directly or indirectly depends on 'any' primitive or group
resources.
Even in newer versions, if a migratable resource depends on a non-migratable
resource, and both need to be moved, the migratable resource will be restarted.
[[s-reusing-config-elements]]
== Reusing Rules, Options and Sets of Operations ==
Sometimes a number of constraints need to use the same set of rules,
and resources need to set the same options and parameters. To
simplify this situation, you can refer to an existing object using an
+id-ref+ instead of an id.
So if for one resource you have
[source,XML]
------
------
Then instead of duplicating the rule for all your other resources, you can instead specify:
.Referencing rules from other constraints
=====
[source,XML]
-------
-------
=====
[IMPORTANT]
===========
The cluster will insist that the +rule+ exists somewhere. Attempting
to add a reference to a non-existing rule will cause a validation
failure, as will attempting to remove a +rule+ that is referenced
elsewhere.
===========
The same principle applies for +meta_attributes+ and
+instance_attributes+ as illustrated in the example below:
.Referencing attributes, options, and operations from other resources
=====
[source,XML]
-------
-------
=====
== 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-Resources.txt b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
index e0d906b04e..1d31e1029e 100644
--- a/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
+++ b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt
@@ -1,846 +1,851 @@
= Cluster Resources =
== What is a Cluster Resource? ==
indexterm:[Resource]
A resource is a service made highly available by a cluster.
The simplest type of resource, a 'primitive' resource, is described
in this chapter. More complex forms, such as groups and clones,
are described in later chapters.
Every primitive resource has a 'resource agent'. A resource agent is an
external program that abstracts the service it provides and present a
consistent view to the cluster.
This allows the cluster to be agnostic about the resources it manages.
The cluster doesn't need to understand how the resource works because
it relies on the resource agent to do the right thing when given a
`start`, `stop` or `monitor` command. For this reason, it is crucial that
resource agents are well-tested.
Typically, resource agents come in the form of shell scripts. However,
they can be written using any technology (such as C, Python or Perl)
that the author is comfortable with.
[[s-resource-supported]]
== Resource Classes ==
indexterm:[Resource,class]
Pacemaker supports several classes of agents:
* OCF
* LSB
* Upstart
* Systemd
* Service
* Fencing
* Nagios Plugins
=== Open Cluster Framework ===
indexterm:[Resource,OCF]
indexterm:[OCF,Resources]
indexterm:[Open Cluster Framework,Resources]
The OCF standard
footnote:[See
http://www.opencf.org/cgi-bin/viewcvs.cgi/specs/ra/resource-agent-api.txt?rev=HEAD
-- at least as it relates to resource agents. The Pacemaker implementation has
been somewhat extended from the OCF specs, but none of those changes are
incompatible with the original OCF specification.]
is basically an extension of the Linux Standard Base conventions for
init scripts to:
* support parameters,
* make them self-describing, and
* make them extensible
OCF specs have strict definitions of the exit codes that actions must return.
footnote:[
The resource-agents source code includes the `ocf-tester` script, which
can be useful in this regard.
]
The cluster follows these specifications exactly, and giving the wrong
exit code will cause the cluster to behave in ways you will likely
find puzzling and annoying. In particular, the cluster needs to
distinguish a completely stopped resource from one which is in some
erroneous and indeterminate state.
Parameters are passed to the resource agent as environment variables, with the
special prefix +OCF_RESKEY_+. So, a parameter which the user thinks
of as +ip+ will be passed to the resource agent as +OCF_RESKEY_ip+. The
number and purpose of the parameters is left to the resource agent; however,
the resource agent should use the `meta-data` command to advertise any that it
supports.
The OCF class is the most preferred as it is an industry standard,
highly flexible (allowing parameters to be passed to agents in a
non-positional manner) and self-describing.
For more information, see the
http://www.linux-ha.org/wiki/OCF_Resource_Agents[reference] and
<>.
=== Linux Standard Base ===
indexterm:[Resource,LSB]
indexterm:[LSB,Resources]
indexterm:[Linux Standard Base,Resources]
LSB resource agents are those found in +/etc/init.d+.
Generally, they are provided by the OS distribution and, in order to be used
with the cluster, they must conform to the LSB Spec.
footnote:[
See
http://refspecs.linux-foundation.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
for the LSB Spec as it relates to init scripts.
]
[WARNING]
====
Many distributions claim LSB compliance but ship with broken init
scripts. For details on how to check whether your init script is
LSB-compatible, see <>. 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.
====
=== 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]
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-------
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[[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> resources, 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]
|resource-stickiness
|value of +resource-stickiness+ in the +rsc_defaults+ section
|How much does the resource prefer to stay where it is?
indexterm:[resource-stickiness,Resource Option]
indexterm:[Resource,Option,resource-stickiness]
|requires
|fencing (unless +stonith-enabled+ is +false+ or +class+ is
+stonith+, in which case it defaults to quorum)
|Conditions under which the resource can be started '(since 1.1.8)'
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 powered off
* +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 powered off _and_ only on nodes that have been 'unfenced'
'(since 1.1.9)'
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 has
on-fail=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
|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 <>)
+
|remote-node
|
|The name of the remote-node this resource defines. This both enables the
resource as a remote-node and defines the unique name used to identify the
remote-node. If no other parameters are set, this value will also be assumed as
the hostname to connect to at the port specified by +remote-port+. +WARNING:+
This value cannot overlap with any resource or node IDs. If not specified,
this feature is disabled.
|remote-port
|3121
|Port to use for the guest connection to pacemaker_remote
|remote-addr
|value of +remote-node+
|The IP address or hostname to connect to if remote-node's name is not the
hostname of the guest.
|+remote-connect-timeout+
|60s
|How long before a pending guest connection will time out.
|=========================================================
[NOTE]
====
Support for remote nodes was added in pacemaker 1.1.10. If you are using an
earlier version, options related to remote nodes will not be available.
====
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
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[source,XML]
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[[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
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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.
Some operations are generated by the cluster itself, for example, stopping and
starting resources as needed.
You can configure operations in the cluster configuration. As an example, by
default the cluster will 'not' ensure your resources stay healthy once they are
started. footnote:[Currently, anyway. Automatic monitoring operations may be
added in a future version of Pacemaker.] To instruct the cluster to do this,
you need to add a +monitor+ operation to the resource's definition.
.An OCF resource with a recurring health check
=====
[source,XML]
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.Properties of an Operation
[width="95%",cols="2m,3,6>.
indexterm:[interval,Action Property]
indexterm:[Action,Property,interval]
|timeout
|
|How long to wait before declaring the action has failed
indexterm:[timeout,Action Property]
indexterm:[Action,Property,timeout]
|on-fail
|restart '(except for stop operations, which default to' fence 'when
STONITH is enabled and' block 'otherwise)'
|The action to take if this action ever fails. Allowed values:
* +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
-|
+|FALSE
|If +true+, the intention to perform the operation is recorded so that
GUIs and CLI tools can indicate that an operation is in progress.
This is best set as an 'operation default' (see next section).
Allowed values: +true+, +false+.
indexterm:[enabled,Action Property]
indexterm:[Action,Property,enabled]
|role
|
|Run the operation only on node(s) that the cluster thinks should be in
the specified role. This only makes sense for recurring monitor operations.
Allowed (case-sensitive) values: +Stopped+, +Started+, and in the
case of <> resources, +Slave+ and +Master+.
indexterm:[role,Action Property]
indexterm:[Action,Property,role]
|=========================================================
[[s-resource-monitoring]]
=== Monitoring Resources for Failure ===
When Pacemaker first starts a resource, it runs one-time monitor operations
(referred to as 'probes') to ensure the resource is running where it's
supposed to be, and not running where it's not supposed to be. (This behavior
can be affected by the +resource-discovery+ location constraint property.)
Other than those initial probes, Pacemaker will not (by default) check that
the resource continues to stay healthy. As in the example above, you must
configure monitor operations explicitly to perform these checks.
By default, a monitor operation will ensure that the resource is running
where it is supposed to. The +target-role+ property can be used for further
checking.
For example, if a resource has one monitor operation with
+interval=10 role=Started+ and a second monitor operation with
+interval=11 role=Stopped+, the cluster will run the first monitor on any nodes
it thinks 'should' be running the resource, and the second monitor on any nodes
that it thinks 'should not' be running the resource (for the truly paranoid,
who want to know when an administrator manually starts a service by mistake).
[[s-monitoring-unmanaged]]
=== Monitoring Resources When Administration is Disabled ===
Recurring monitor operations behave differently under various administrative
settings:
* When a resource is unmanaged (by setting +is-managed=false+): No monitors
will be stopped.
+
If the unmanaged resource is stopped on a node where the cluster thinks it
should be running, the cluster will detect and report that it is not, but it
will not consider the monitor failed, and will not try to start the resource
until it is managed again.
+
Starting the unmanaged resource on a different node is strongly discouraged
and will at least cause the cluster to consider the resource failed, and
may require the resource's +target-role+ to be set to +Stopped+ then +Started+
to be recovered.
* When a node is put into standby: All resources will be moved away from the
node, and all monitor operations will be stopped on the node, except those
with +role=Stopped+. Monitor operations with +role=Stopped+ will be started
on the node if appropriate.
* When the cluster is put into maintenance mode: All resources will be marked
as unmanaged. All monitor operations will be stopped, except those with
+role=Stopped+. As with single unmanaged resources, starting a resource
on a node other than where the cluster expects it to be will cause problems.
[[s-operation-defaults]]
=== Setting Global Defaults for Operations ===
You can change the global default values for operation properties
in a given cluster. These are defined in an +op_defaults+ section
of the CIB's +configuration+ section, and can be set with `crm_attribute`.
For example,
----
# crm_attribute --type op_defaults --name timeout --update 20s
----
would default each operation's +timeout+ to 20 seconds. If an
operation's definition also includes a value for +timeout+, then that
value would be used for that operation instead.
=== When Implicit Operations Take a Long Time ===
The cluster will always perform a number of implicit operations: +start+,
+stop+ and a non-recurring +monitor+ operation used at startup to check
whether the resource is already active. If one of these is taking too long,
then you can create an entry for them and specify a longer timeout.
.An OCF resource with custom timeouts for its implicit actions
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[source,XML]
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=== 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]
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=== 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]
-------
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=====
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 ''
----