diff --git a/doc/sphinx/Pacemaker_Explained/advanced-resources.rst b/doc/sphinx/Pacemaker_Explained/advanced-resources.rst
index 9f348e3467..e8bd643e13 100644
--- a/doc/sphinx/Pacemaker_Explained/advanced-resources.rst
+++ b/doc/sphinx/Pacemaker_Explained/advanced-resources.rst
@@ -1,1480 +1,1487 @@
Advanced Resource Types
-----------------------
+.. _group-resources:
+
+Groups - A Syntactic Shortcut
+=============================
+
.. Convert_to_RST:
- [[group-resources]]
- == Groups - A Syntactic Shortcut ==
indexterm:[Group Resources]
indexterm:[Resource,Groups]
One of the most common elements of a cluster is a set of resources
that need to be located together, start sequentially, and stop in the
reverse order. To simplify this configuration, we support the concept
of groups.
.A group of two primitive resources
======
[source,XML]
-------
-------
======
Although the example above contains only two resources, there is no
limit to the number of resources a group can contain. The example is
also sufficient to explain the fundamental properties of a group:
* Resources are started in the order they appear in (+Public-IP+
first, then +Email+)
* Resources are stopped in the reverse order to which they appear in
(+Email+ first, then +Public-IP+)
If a resource in the group can't run anywhere, then nothing after that
is allowed to run, too.
* If +Public-IP+ can't run anywhere, neither can +Email+;
* but if +Email+ can't run anywhere, this does not affect +Public-IP+
in any way
The group above is logically equivalent to writing:
.How the cluster sees a group resource
======
[source,XML]
-------
-------
======
Obviously as the group grows bigger, the reduced configuration effort
can become significant.
Another (typical) example of a group is a DRBD volume, the filesystem
mount, an IP address, and an application that uses them.
=== Group Properties ===
.Properties of a Group Resource
[width="95%",cols="3m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the group
indexterm:[id,Group Resource Property]
indexterm:[Resource,Group Property,id]
|=========================================================
=== Group Options ===
Groups inherit the +priority+, +target-role+, and +is-managed+ properties
from primitive resources. See <> for information about
those properties.
=== Group Instance Attributes ===
Groups have no instance attributes. However, any that are set for the group
object will be inherited by the group's children.
=== Group Contents ===
Groups may only contain a collection of cluster resources (see
<>). To refer to a child of a group resource, just use
the child's +id+ instead of the group's.
=== Group Constraints ===
Although it is possible to reference a group's children in
constraints, it is usually preferable to reference the group itself.
.Some constraints involving groups
======
[source,XML]
-------
-------
======
=== Group Stickiness ===
indexterm:[resource-stickiness,Groups]
Stickiness, the measure of how much a resource wants to stay where it
is, is additive in groups. Every active resource of the group will
contribute its stickiness value to the group's total. So if the
default +resource-stickiness+ is 100, and a group has seven members,
five of which are active, then the group as a whole will prefer its
current location with a score of 500.
[[s-resource-clone]]
== Clones - Resources That Can Have Multiple Active Instances ==
indexterm:[Clone Resources]
indexterm:[Resource,Clones]
'Clone' resources are resources that can have more than one copy active at the
same time. This allows you, for example, to run a copy of a daemon on every
node. You can clone any primitive or group resource.
footnote:[
Of course, the service must support running multiple instances.
]
=== Anonymous versus Unique Clones ===
A clone resource is configured to be either 'anonymous' or 'globally unique'.
Anonymous clones are the simplest. These behave completely identically
everywhere they are running. Because of this, there can be only one instance of
an anonymous clone active per node.
The instances of globally unique clones are distinct entities. All instances
are launched identically, but one instance of the clone is not identical to any
other instance, whether running on the same node or a different node. As an
example, a cloned IP address can use special kernel functionality such that
each instance handles a subset of requests for the same IP address.
-
- [[s-resource-promotable]]
- === Promotable clones ===
+
+.. _s-resource-promotable:
+
+Promotable clones
+_________________
+
+.. Convert_to_RST:
indexterm:[Promotable Clone Resources]
indexterm:[Resource,Promotable]
If a clone is 'promotable', its instances can perform a special role that
Pacemaker will manage via the +promote+ and +demote+ actions of the resource
agent.
Services that support such a special role have various terms for the special
role and the default role: primary and secondary, master and replica,
controller and worker, etc. Pacemaker uses the terms 'master' and 'slave',
footnote:[
These are historical terms that will eventually be replaced, but the extensive
use of them and the need for backward compatibility makes it a long process.
You may see examples using a +master+ tag instead of a +clone+ tag with the
+promotable+ meta-attribute set to +true+; the +master+ tag is supported, but
deprecated, and will be removed in a future version. You may also see such
services referred to as 'multi-state' or 'stateful'; these means the same thing
as 'promotable'.
]
but is agnostic to what the service calls them or what they do.
All that Pacemaker cares about is that an instance comes up in the default role
when started, and the resource agent supports the +promote+ and +demote+ actions
to manage entering and exiting the special role.
=== Clone Properties ===
.Properties of a Clone Resource
[width="95%",cols="3m,<5",options="header",align="center"]
|=========================================================
|Field
|Description
|id
|A unique name for the clone
indexterm:[id,Clone Property]
indexterm:[Clone,Property,id]
|=========================================================
=== Clone Options ===
<> inherited from primitive resources:
+priority, target-role, is-managed+
.Clone-specific configuration options
[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|globally-unique
|false
|If +true+, each clone instance performs a distinct function
indexterm:[globally-unique,Clone Option]
indexterm:[Clone,Option,globally-unique]
|clone-max
|number of nodes in cluster
|The maximum number of clone instances that can be started across the entire
cluster
indexterm:[clone-max,Clone Option]
indexterm:[Clone,Option,clone-max]
|clone-node-max
|1
|If +globally-unique+ is +true+, the maximum number of clone instances that can
be started on a single node
indexterm:[clone-node-max,Clone Option]
indexterm:[Clone,Option,clone-node-max]
|clone-min
|0
|Require at least this number of clone instances to be runnable before allowing
resources depending on the clone to be runnable. A value of 0 means require
all clone instances to be runnable.
indexterm:[clone-min,Clone Option]
indexterm:[Clone,Option,clone-min]
|notify
|false
|Call the resource agent's +notify+ action for all active instances, before and
after starting or stopping any clone instance. The resource agent must support
this action. Allowed values: +false+, +true+
indexterm:[notify,Clone Option]
indexterm:[Clone,Option,notify]
|ordered
|false
|If +true+, clone instances must be started sequentially instead of in parallel
Allowed values: +false+, +true+
indexterm:[ordered,Clone Option]
indexterm:[Clone,Option,ordered]
|interleave
|false
|When this clone is ordered relative to another clone, if this option is
+false+ (the default), the ordering is relative to 'all' instances of the
other clone, whereas if this option is +true+, the ordering is relative only
to instances on the same node.
Allowed values: +false+, +true+
indexterm:[interleave,Clone Option]
indexterm:[Clone,Option,interleave]
|promotable
|false
|If +true+, clone instances can perform a special role that Pacemaker will
manage via the resource agent's +promote+ and +demote+ actions. The resource
agent must support these actions.
Allowed values: +false+, +true+
indexterm:[promotable,Clone Option]
indexterm:[Clone,Option,promotable]
|promoted-max
|1
|If +promotable+ is +true+, the number of instances that can be promoted at one
time across the entire cluster
indexterm:[promoted-max,Clone Option]
indexterm:[Clone,Option,promoted-max]
|promoted-node-max
|1
|If +promotable+ is +true+ and +globally-unique+ is +false+, the number of
clone instances can be promoted at one time on a single node
indexterm:[promoted-node-max,Clone Option]
indexterm:[Clone,Option,promoted-node-max]
|=========================================================
For backward compatibility, +master-max+ and +master-node-max+ are accepted as
aliases for +promoted-max+ and +promoted-node-max+, but are deprecated since
2.0.0, and support for them will be removed in a future version.
=== Clone Contents ===
Clones must contain exactly one primitive or group resource.
.A clone that runs a web server on all nodes
====
[source,XML]
----
----
====
[WARNING]
You should never reference the name of a clone's child (the primitive or group
resource being cloned). If you think you need to do this, you probably need to
re-evaluate your design.
=== Clone Instance Attributes ===
Clones have no instance attributes; however, any that are set here will be
inherited by the clone's child.
=== Clone Constraints ===
In most cases, a clone will have a single instance on each active cluster
node. If this is not the case, you can indicate which nodes the
cluster should preferentially assign copies to with resource location
constraints. These constraints are written no differently from those
for primitive resources except that the clone's +id+ is used.
.Some constraints involving clones
======
[source,XML]
-------
-------
======
Ordering constraints behave slightly differently for clones. In the
example above, +apache-stats+ will wait until all copies of +apache-clone+
that need to be started have done so before being started itself.
Only if _no_ copies can be started will +apache-stats+ be prevented
from being active. Additionally, the clone will wait for
+apache-stats+ to be stopped before stopping itself.
Colocation of a primitive or group resource with a clone means that
the resource can run on any node with an active instance of the clone.
The cluster will choose an instance based on where the clone is running and
the resource's own location preferences.
Colocation between clones is also possible. If one clone +A+ is colocated
with another clone +B+, the set of allowed locations for +A+ is limited to
nodes on which +B+ is (or will be) active. Placement is then performed
normally.
==== Promotable Clone Constraints ====
For promotable clone resources, the +first-action+ and/or +then-action+ fields
for ordering constraints may be set to +promote+ or +demote+ to constrain the
master role, and colocation constraints may contain +rsc-role+ and/or
+with-rsc-role+ fields.
.Additional colocation constraint options for promotable clone resources
[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|rsc-role
|Started
|An additional attribute of colocation constraints that specifies the
role that +rsc+ must be in. Allowed values: +Started+, +Master+,
+Slave+.
indexterm:[rsc-role,Ordering Constraints]
indexterm:[Constraints,Ordering,rsc-role]
|with-rsc-role
|Started
|An additional attribute of colocation constraints that specifies the
role that +with-rsc+ must be in. Allowed values: +Started+,
+Master+, +Slave+.
indexterm:[with-rsc-role,Ordering Constraints]
indexterm:[Constraints,Ordering,with-rsc-role]
|=========================================================
.Constraints involving promotable clone resources
======
[source,XML]
-------
-------
======
In the example above, +myApp+ will wait until one of the database
copies has been started and promoted to master before being started
itself on the same node. Only if no copies can be promoted will +myApp+ be
prevented from being active. Additionally, the cluster will wait for
+myApp+ to be stopped before demoting the database.
Colocation of a primitive or group resource with a promotable clone
resource means that it can run on any node with an active instance of
the promotable clone resource that has the specified role (+master+ or
+slave+). In the example above, the cluster will choose a location based on
where database is running as a +master+, and if there are multiple
+master+ instances it will also factor in +myApp+'s own location
preferences when deciding which location to choose.
Colocation with regular clones and other promotable clone resources is also
possible. In such cases, the set of allowed locations for the +rsc+
clone is (after role filtering) limited to nodes on which the
+with-rsc+ promotable clone resource is (or will be) in the specified role.
Placement is then performed as normal.
==== Using Promotable Clone Resources in Colocation Sets ====
.Additional colocation set options relevant to promotable clone resources
[width="95%",cols="1m,1,<6",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|role
|Started
|The role that 'all members' of the set must be in. Allowed values: +Started+, +Master+,
+Slave+.
indexterm:[role,Ordering Constraints]
indexterm:[Constraints,Ordering,role]
|=========================================================
In the following example +B+'s master must be located on the same node as +A+'s master.
Additionally resources +C+ and +D+ must be located on the same node as +A+'s
and +B+'s masters.
.Colocate C and D with A's and B's master instances
======
[source,XML]
-------
-------
======
==== Using Promotable Clone Resources in Ordered Sets ====
.Additional ordered set options relevant to promotable clone resources
[width="95%",cols="1m,1,<3",options="header",align="center"]
|=========================================================
|Field
|Default
|Description
|action
|value of +first-action+
|An additional attribute of ordering constraint sets that specifies the
action that applies to 'all members' of the set. Allowed
values: +start+, +stop+, +promote+, +demote+.
indexterm:[action,Ordering Constraints]
indexterm:[Constraints,Ordering,action]
|=========================================================
.Start C and D after first promoting A and B
======
[source,XML]
-------
-------
======
In the above example, +B+ cannot be promoted to a master role until +A+ has
been promoted. Additionally, resources +C+ and +D+ must wait until +A+ and +B+
have been promoted before they can start.
[[s-clone-stickiness]]
=== Clone Stickiness ===
indexterm:[resource-stickiness,Clones]
To achieve a stable allocation pattern, clones are slightly sticky by
default. If no value for +resource-stickiness+ is provided, the clone
will use a value of 1. Being a small value, it causes minimal
disturbance to the score calculations of other resources but is enough
to prevent Pacemaker from needlessly moving copies around the cluster.
[NOTE]
====
For globally unique clones, this may result in multiple instances of the
clone staying on a single node, even after another eligible node becomes
active (for example, after being put into standby mode then made active again).
If you do not want this behavior, specify a +resource-stickiness+ of 0
for the clone temporarily and let the cluster adjust, then set it back
to 1 if you want the default behavior to apply again.
====
[IMPORTANT]
====
If +resource-stickiness+ is set in the +rsc_defaults+ section, it will
apply to clone instances as well. This means an explicit +resource-stickiness+
of 0 in +rsc_defaults+ works differently from the implicit default used when
+resource-stickiness+ is not specified.
====
=== Clone Resource Agent Requirements ===
Any resource can be used as an anonymous clone, as it requires no
additional support from the resource agent. Whether it makes sense to
do so depends on your resource and its resource agent.
==== Resource Agent Requirements for Globally Unique Clones ====
Globally unique clones require additional support in the resource agent. In
particular, it must only respond with +$\{OCF_SUCCESS}+ if the node has that
exact instance active. All other probes for instances of the clone should
result in +$\{OCF_NOT_RUNNING}+ (or one of the other OCF error codes if
they are failed).
Individual instances of a clone are identified by appending a colon and a
numerical offset, e.g. +apache:2+.
Resource agents can find out how many copies there are by examining
the +OCF_RESKEY_CRM_meta_clone_max+ environment variable and which
instance it is by examining +OCF_RESKEY_CRM_meta_clone+.
The resource agent must not make any assumptions (based on
+OCF_RESKEY_CRM_meta_clone+) about which numerical instances are active. In
particular, the list of active copies will not always be an unbroken
sequence, nor always start at 0.
==== Resource Agent Requirements for Promotable Clones ====
Promotable clone resources require two extra actions, +demote+ and +promote+,
which are responsible for changing the state of the resource. Like +start+ and
+stop+, they should return +$\{OCF_SUCCESS}+ if they completed successfully or
a relevant error code if they did not.
The states can mean whatever you wish, but when the resource is
started, it must come up in the mode called +slave+. From there the
cluster will decide which instances to promote to +master+.
In addition to the clone requirements for monitor actions, agents must
also _accurately_ report which state they are in. The cluster relies
on the agent to report its status (including role) accurately and does
not indicate to the agent what role it currently believes it to be in.
.Role implications of OCF return codes
[width="95%",cols="1,<1",options="header",align="center"]
|=========================================================
|Monitor Return Code
|Description
|OCF_NOT_RUNNING
|Stopped
indexterm:[Return Code,OCF_NOT_RUNNING]
|OCF_SUCCESS
|Running (Slave)
indexterm:[Return Code,OCF_SUCCESS]
|OCF_RUNNING_MASTER
|Running (Master)
indexterm:[Return Code,OCF_RUNNING_MASTER]
|OCF_FAILED_MASTER
|Failed (Master)
indexterm:[Return Code,OCF_FAILED_MASTER]
|Other
|Failed (Slave)
|=========================================================
==== Clone Notifications ====
If the clone has the +notify+ meta-attribute set to +true+, and the resource
agent supports the +notify+ action, Pacemaker will call the action when
appropriate, passing a number of extra variables which, when combined with
additional context, can be used to calculate the current state of the cluster
and what is about to happen to it.
.Environment variables supplied with Clone notify actions
[width="95%",cols="5,<3",options="header",align="center"]
|=========================================================
|Variable
|Description
|OCF_RESKEY_CRM_meta_notify_type
|Allowed values: +pre+, +post+
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,type]
indexterm:[type,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_operation
|Allowed values: +start+, +stop+
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,operation]
indexterm:[operation,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_start_resource
|Resources to be started
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_resource]
indexterm:[start_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_stop_resource
|Resources to be stopped
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_resource]
indexterm:[stop_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_active_resource
|Resources that are running
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_resource]
indexterm:[active_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_inactive_resource
|Resources that are not running
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,inactive_resource]
indexterm:[inactive_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_start_uname
|Nodes on which resources will be started
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_uname]
indexterm:[start_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_stop_uname
|Nodes on which resources will be stopped
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_uname]
indexterm:[stop_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_active_uname
|Nodes on which resources are running
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_uname]
indexterm:[active_uname,Notification Environment Variable]
|=========================================================
The variables come in pairs, such as
+OCF_RESKEY_CRM_meta_notify_start_resource+ and
+OCF_RESKEY_CRM_meta_notify_start_uname+, and should be treated as an
array of whitespace-separated elements.
+OCF_RESKEY_CRM_meta_notify_inactive_resource+ is an exception, as the
matching +uname+ variable does not exist since inactive resources
are not running on any node.
Thus, in order to indicate that +clone:0+ will be started on +sles-1+,
+clone:2+ will be started on +sles-3+, and +clone:3+ will be started
on +sles-2+, the cluster would set:
.Notification variables
======
[source,Bash]
-------
OCF_RESKEY_CRM_meta_notify_start_resource="clone:0 clone:2 clone:3"
OCF_RESKEY_CRM_meta_notify_start_uname="sles-1 sles-3 sles-2"
-------
======
[NOTE]
====
Pacemaker will log but otherwise ignore failures of notify actions.
====
==== Interpretation of Notification Variables ====
.Pre-notification (stop):
* Active resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+
* Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (stop) / Pre-notification (start):
* Active resources
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Inactive resources
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (start):
* Active resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
==== Extra Notifications for Promotable Clones ====
.Extra environment variables supplied for promotable clones
[width="95%",cols="5,<3",options="header",align="center"]
|=========================================================
|Variable
|Description
|OCF_RESKEY_CRM_meta_notify_master_resource
|Resources that are running in +Master+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,master_resource]
indexterm:[master_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_slave_resource
|Resources that are running in +Slave+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,slave_resource]
indexterm:[slave_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_promote_resource
|Resources to be promoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,promote_resource]
indexterm:[promote_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_demote_resource
|Resources to be demoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,demote_resource]
indexterm:[demote_resource,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_promote_uname
|Nodes on which resources will be promoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,promote_uname]
indexterm:[promote_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_demote_uname
|Nodes on which resources will be demoted
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,demote_uname]
indexterm:[demote_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_master_uname
|Nodes on which resources are running in +Master+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,master_uname]
indexterm:[master_uname,Notification Environment Variable]
|OCF_RESKEY_CRM_meta_notify_slave_uname
|Nodes on which resources are running in +Slave+ mode
indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,slave_uname]
indexterm:[slave_uname,Notification Environment Variable]
|=========================================================
==== Interpretation of Promotable Notification Variables ====
.Pre-notification (demote):
* +Active+ resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+
* +Master+ resources: +$OCF_RESKEY_CRM_meta_notify_master_resource+
* +Slave+ resources: +$OCF_RESKEY_CRM_meta_notify_slave_resource+
* Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (demote) / Pre-notification (stop):
* +Active+ resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* +Slave+ resources: +$OCF_RESKEY_CRM_meta_notify_slave_resource+
* Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
.Post-notification (stop) / Pre-notification (start)
* +Active+ resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* +Slave+ resources:
** +$OCF_RESKEY_CRM_meta_notify_slave_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (start) / Pre-notification (promote)
* +Active+ resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* +Slave+ resources:
** +$OCF_RESKEY_CRM_meta_notify_slave_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
.Post-notification (promote)
* +Active+ resources:
** +$OCF_RESKEY_CRM_meta_notify_active_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* +Master+ resources:
** +$OCF_RESKEY_CRM_meta_notify_master_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* +Slave+ resources:
** +$OCF_RESKEY_CRM_meta_notify_slave_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Inactive resources:
** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+
** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+
** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
* Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+
* Resources that were promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+
* Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+
* Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+
=== Monitoring Promotable Clone Resources ===
The usual monitor actions are insufficient to monitor a promotable clone
resource, because Pacemaker needs to verify not only that the resource is
active, but also that its actual role matches its intended one.
Define two monitoring actions: the usual one will cover the slave role,
and an additional one with +role="master"+ will cover the master role.
.Monitoring both states of a promotable clone resource
======
[source,XML]
-------
-------
======
[IMPORTANT]
===========
It is crucial that _every_ monitor operation has a different interval!
Pacemaker currently differentiates between operations
only by resource and interval; so if (for example) a promotable clone resource
had the same monitor interval for both roles, Pacemaker would ignore the
role when checking the status -- which would cause unexpected return
codes, and therefore unnecessary complications.
===========
[[s-promotion-scores]]
=== Determining Which Instance is Promoted ===
Pacemaker can choose a promotable clone instance to be promoted in one of two
ways:
* Promotion scores: These are node attributes set via the `crm_master` utility,
which generally would be called by the resource agent's start action if it
supports promotable clones. This tool automatically detects both the resource
and host, and should be used to set a preference for being promoted. Based on
this, +promoted-max+, and +promoted-node-max+, the instance(s) with the
highest preference will be promoted.
* Constraints: Location constraints can indicate which nodes are most preferred
as masters.
.Explicitly preferring node1 to be promoted to master
======
[source,XML]
-------
-------
======
[[s-resource-bundle]]
== Bundles - Isolated Environments ==
indexterm:[Resource,Bundle]
indexterm:[Container,Docker,Bundle]
indexterm:[Container,podman,Bundle]
indexterm:[Container,rkt,Bundle]
Pacemaker supports a special syntax for launching a
https://en.wikipedia.org/wiki/Operating-system-level_virtualization[container]
with any infrastructure it requires: the 'bundle'.
Pacemaker bundles support https://www.docker.com/[Docker],
https://podman.io/[podman], and https://coreos.com/rkt/[rkt]
container technologies.
footnote:[Docker is a trademark of Docker, Inc. No endorsement by or
association with Docker, Inc. is implied.]
.A bundle for a containerized web server
====
[source,XML]
----
----
====
=== Bundle Prerequisites ===
indexterm:[Resource,Bundle,Prerequisites]
Before configuring a bundle in Pacemaker, the user must install the appropriate
container launch technology (Docker, podman, or rkt), and supply a fully
configured container image, on every node allowed to run the bundle.
Pacemaker will create an implicit resource of type +ocf:heartbeat:docker+,
+ocf:heartbeat:podman+, or +ocf:heartbeat:rkt+ to manage a bundle's
container. The user must ensure that the appropriate resource agent is
installed on every node allowed to run the bundle.
=== Bundle Properties ===
indexterm:[XML element,bundle element]
.XML Attributes of a bundle Element
[width="95%",cols="3m,<5",options="header",align="center"]
|=========================================================
|Attribute
|Description
|id
|A unique name for the bundle (required)
indexterm:[XML attribute,id attribute,bundle element]
indexterm:[XML element,bundle element,id attribute]
|description
|Arbitrary text (not used by Pacemaker)
indexterm:[XML attribute,description attribute,bundle element]
indexterm:[XML element,bundle element,description attribute]
|=========================================================
A bundle must contain exactly one +docker+, +podman+, or +rkt+ element.
=== Bundle Container Properties ===
indexterm:[XML element,docker element]
indexterm:[XML element,podman element]
indexterm:[XML element,rkt element]
indexterm:[Resource,Bundle,Container]
.XML attributes of a docker, podman, or rkt Element
[width="95%",cols="3m,4,<5",options="header",align="center"]
|====
|Attribute
|Default
|Description
|image
|
|Container image tag (required)
indexterm:[XML attribute,image attribute,docker element]
indexterm:[XML element,docker element,image attribute]
indexterm:[XML attribute,image attribute,podman element]
indexterm:[XML element,podman element,image attribute]
indexterm:[XML attribute,image attribute,rkt element]
indexterm:[XML element,rkt element,image attribute]
|replicas
|Value of +promoted-max+ if that is positive, else 1
|A positive integer specifying the number of container instances to launch
indexterm:[XML attribute,replicas attribute,docker element]
indexterm:[XML element,docker element,replicas attribute]
indexterm:[XML attribute,replicas attribute,podman element]
indexterm:[XML element,podman element,replicas attribute]
indexterm:[XML attribute,replicas attribute,rkt element]
indexterm:[XML element,rkt element,replicas attribute]
|replicas-per-host
|1
|A positive integer specifying the number of container instances allowed to run
on a single node
indexterm:[XML attribute,replicas-per-host attribute,docker element]
indexterm:[XML element,docker element,replicas-per-host attribute]
indexterm:[XML attribute,replicas-per-host attribute,podman element]
indexterm:[XML element,podman element,replicas-per-host attribute]
indexterm:[XML attribute,replicas-per-host attribute,rkt element]
indexterm:[XML element,rkt element,replicas-per-host attribute]
|promoted-max
|0
|A non-negative integer that, if positive, indicates that the containerized
service should be treated as a promotable service, with this many replicas
allowed to run the service in the master role
indexterm:[XML attribute,promoted-max attribute,docker element]
indexterm:[XML element,docker element,promoted-max attribute]
indexterm:[XML attribute,promoted-max attribute,podman element]
indexterm:[XML element,podman element,promoted-max attribute]
indexterm:[XML attribute,promoted-max attribute,rkt element]
indexterm:[XML element,rkt element,promoted-max attribute]
|network
|
|If specified, this will be passed to the `docker run`, `podman run`, or
`rkt run` command as the network setting for the container.
indexterm:[XML attribute,network attribute,docker element]
indexterm:[XML element,docker element,network attribute]
indexterm:[XML attribute,network attribute,podman element]
indexterm:[XML element,podman element,network attribute]
indexterm:[XML attribute,network attribute,rkt element]
indexterm:[XML element,rkt element,network attribute]
|run-command
|`/usr/sbin/pacemaker-remoted` if bundle contains a +primitive+, otherwise none
|This command will be run inside the container when launching it ("PID 1"). If
the bundle contains a +primitive+, this command 'must' start pacemaker-remoted
(but could, for example, be a script that does other stuff, too).
indexterm:[XML attribute,run-command attribute,docker element]
indexterm:[XML element,docker element,run-command attribute]
indexterm:[XML attribute,run-command attribute,podman element]
indexterm:[XML element,podman element,run-command attribute]
indexterm:[XML attribute,run-command attribute,rkt element]
indexterm:[XML element,rkt element,run-command attribute]
|options
|
|Extra command-line options to pass to the `docker run`, `podman run`, or
`rkt run` command
indexterm:[XML attribute,options attribute,docker element]
indexterm:[XML element,docker element,options attribute]
indexterm:[XML attribute,options attribute,podman element]
indexterm:[XML element,podman element,options attribute]
indexterm:[XML attribute,options attribute,rkt element]
indexterm:[XML element,rkt element,options attribute]
|====
[NOTE]
====
Considerations when using cluster configurations or container images from
Pacemaker 1.1:
- If the container image has a pre-2.0.0 version of Pacemaker, set +run-command+
to +/usr/sbin/pacemaker_remoted+ (note the underbar instead of dash).
- +masters+ is accepted as an alias for +promoted-max+, but is deprecated since
2.0.0, and support for it will be removed in a future version.
====
=== Bundle Network Properties ===
A bundle may optionally contain one ++ element.
indexterm:[XML element,network element]
indexterm:[Resource,Bundle,Networking]
.XML attributes of a network Element
[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Attribute
|Default
|Description
|add-host
|TRUE
|If TRUE, and +ip-range-start+ is used, Pacemaker will automatically ensure
that +/etc/hosts+ inside the containers has entries for each
<> and its assigned IP.
indexterm:[XML element,add-host attribute,network element]
indexterm:[XML attribute,network element,add-host attribute]
|ip-range-start
|
|If specified, Pacemaker will create an implicit +ocf:heartbeat:IPaddr2+
resource for each container instance, starting with this IP address,
using up to +replicas+ sequential addresses. These addresses can be used
from the host's network to reach the service inside the container, though
it is not visible within the container itself. Only IPv4 addresses are
currently supported.
indexterm:[XML element,ip-range-start attribute,network element]
indexterm:[XML attribute,network element,ip-range-start attribute]
|host-netmask
|32
|If +ip-range-start+ is specified, the IP addresses are created with this
CIDR netmask (as a number of bits).
indexterm:[XML element,host-netmask attribute,network element]
indexterm:[XML attribute,network element,host-netmask attribute]
|host-interface
|
|If +ip-range-start+ is specified, the IP addresses are created on this
host interface (by default, it will be determined from the IP address).
indexterm:[XML element,host-interface attribute,network element]
indexterm:[XML attribute,network element,host-interface attribute]
|control-port
|3121
|If the bundle contains a +primitive+, the cluster will use this integer TCP
port for communication with Pacemaker Remote inside the container. Changing
this is useful when the container is unable to listen on the default port,
for example, when the container uses the host's network rather than
+ip-range-start+ (in which case +replicas-per-host+ must be 1), or when the
bundle may run on a Pacemaker Remote node that is already listening on the
default port. Any PCMK_remote_port environment variable set on the host or in
the container is ignored for bundle connections.
indexterm:[XML element,control-port attribute,network element]
indexterm:[XML attribute,network element,control-port attribute]
|=========================================================
[[s-resource-bundle-note-replica-names]]
[NOTE]
====
Replicas are named by the bundle id plus a dash and an integer counter starting
with zero. For example, if a bundle named +httpd-bundle+ has +replicas=2+, its
containers will be named +httpd-bundle-0+ and +httpd-bundle-1+.
====
Additionally, a +network+ element may optionally contain one or more
+port-mapping+ elements.
indexterm:[XML element,port-mapping]
.Attributes of a port-mapping Element
[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Attribute
|Default
|Description
|id
|
|A unique name for the port mapping (required)
indexterm:[XML attribute,id attribute,port-mapping element]
indexterm:[XML element,port-mapping element,id attribute]
|port
|
|If this is specified, connections to this TCP port number on the host network
(on the container's assigned IP address, if +ip-range-start+ is specified)
will be forwarded to the container network. Exactly one of +port+ or +range+
must be specified in a +port-mapping+.
indexterm:[XML attribute,port attribute,port-mapping element]
indexterm:[XML element,port-mapping element,port attribute]
|internal-port
|value of +port+
|If +port+ and this are specified, connections to +port+ on the host's network
will be forwarded to this port on the container network.
indexterm:[XML attribute,internal-port attribute,port-mapping element]
indexterm:[XML element,port-mapping element,internal-port attribute]
|range
|
|If this is specified, connections to these TCP port numbers (expressed as
'first_port'-'last_port') on the host network (on the container's assigned IP
address, if +ip-range-start+ is specified) will be forwarded to the same ports
in the container network. Exactly one of +port+ or +range+ must be specified
in a +port-mapping+.
indexterm:[XML attribute,range attribute,port-mapping element]
indexterm:[XML element,port-mapping element,range attribute]
|=========================================================
[NOTE]
====
If the bundle contains a +primitive+, Pacemaker will automatically map the
+control-port+, so it is not necessary to specify that port in a
+port-mapping+.
====
[[s-bundle-storage]]
=== Bundle Storage Properties ===
A bundle may optionally contain one +storage+ element. A +storage+ element
has no properties of its own, but may contain one or more +storage-mapping+
elements.
indexterm:[XML element,storage element]
indexterm:[XML element,storage-mapping element]
indexterm:[Resource,Bundle,Storage]
.Attributes of a storage-mapping Element
[width="95%",cols="2m,1,<4",options="header",align="center"]
|=========================================================
|Attribute
|Default
|Description
|id
|
|A unique name for the storage mapping (required)
indexterm:[XML attribute,id attribute,storage-mapping element]
indexterm:[XML element,storage-mapping element,id attribute]
|source-dir
|
|The absolute path on the host's filesystem that will be mapped into the
container. Exactly one of +source-dir+ and +source-dir-root+ must be specified
in a +storage-mapping+.
indexterm:[XML attribute,source-dir attribute,storage-mapping element]
indexterm:[XML element,storage-mapping element,source-dir attribute]
|source-dir-root
|
|The start of a path on the host's filesystem that will be mapped into the
container, using a different subdirectory on the host for each container
instance. The subdirectory will be named the same as the
<>.
Exactly one of +source-dir+ and +source-dir-root+ must be specified in a
+storage-mapping+.
indexterm:[XML attribute,source-dir-root attribute,storage-mapping element]
indexterm:[XML element,storage-mapping element,source-dir-root attribute]
|target-dir
|
|The path name within the container where the host storage will be mapped
(required)
indexterm:[XML attribute,target-dir attribute,storage-mapping element]
indexterm:[XML element,storage-mapping element,target-dir attribute]
|options
|
|A comma-separated list of file system mount options to use when mapping the
storage
indexterm:[XML attribute,options attribute,storage-mapping element]
indexterm:[XML element,storage-mapping element,options attribute]
|=========================================================
[NOTE]
====
Pacemaker does not define the behavior if the source directory does not already
exist on the host. However, it is expected that the container technology and/or
its resource agent will create the source directory in that case.
====
[NOTE]
====
If the bundle contains a +primitive+,
Pacemaker will automatically map the equivalent of
+source-dir=/etc/pacemaker/authkey target-dir=/etc/pacemaker/authkey+
and +source-dir-root=/var/log/pacemaker/bundles target-dir=/var/log+ into the
container, so it is not necessary to specify those paths in a
+storage-mapping+.
====
[IMPORTANT]
====
The +PCMK_authkey_location+ environment variable must not be set to anything
other than the default of `/etc/pacemaker/authkey` on any node in the cluster.
====
[IMPORTANT]
====
If SELinux is used in enforcing mode on the host, you must ensure the container
is allowed to use any storage you mount into it. For Docker and podman bundles,
adding "Z" to the mount options will create a container-specific label for the
mount that allows the container access.
====
=== Bundle Primitive ===
indexterm:[Resource,Bundle,Primitive]
A bundle may optionally contain one <>
resource. The primitive may have operations, instance attributes, and
meta-attributes defined, as usual.
If a bundle contains a primitive resource, the container image must include
the Pacemaker Remote daemon, and at least one of +ip-range-start+ or
+control-port+ must be configured in the bundle. Pacemaker will create an
implicit +ocf:pacemaker:remote+ resource for the connection, launch
Pacemaker Remote within the container, and monitor and manage the primitive
resource via Pacemaker Remote.
If the bundle has more than one container instance (replica), the primitive
resource will function as an implicit <> -- a
<> if the bundle has +masters+ greater
than zero.
[NOTE]
====
If you want to pass environment variables to a bundle's Pacemaker Remote
connection or primitive, you have two options:
* Environment variables whose value is the same regardless of the underlying host
may be set using the container element's +options+ attribute.
* If you want variables to have host-specific values, you can use the
<> element to map a file on the host as
+/etc/pacemaker/pcmk-init.env+ in the container. Pacemaker Remote will parse
this file as a shell-like format, with variables set as NAME=VALUE, ignoring
blank lines and comments starting with "#".
====
[IMPORTANT]
====
When a bundle has a +primitive+, Pacemaker on all cluster nodes must be able to
contact Pacemaker Remote inside the bundle's containers.
* The containers must have an accessible network (for example, +network+ should
not be set to "none" with a +primitive+).
* The default, using a distinct network space inside the container, works in
combination with +ip-range-start+. Any firewall must allow access from all
cluster nodes to the +control-port+ on the container IPs.
* If the container shares the host's network space (for example, by setting
+network+ to "host"), a unique +control-port+ should be specified for each
bundle. Any firewall must allow access from all cluster nodes to the
+control-port+ on all cluster and remote node IPs.
====
[[s-bundle-attributes]]
=== Bundle Node Attributes ===
indexterm:[Resource,Bundle,Node Attributes]
If the bundle has a +primitive+, the primitive's resource agent may want to set
node attributes such as <>. However, with
containers, it is not apparent which node should get the attribute.
If the container uses shared storage that is the same no matter which node the
container is hosted on, then it is appropriate to use the promotion score on the
bundle node itself.
On the other hand, if the container uses storage exported from the underlying host,
then it may be more appropriate to use the promotion score on the underlying host.
Since this depends on the particular situation, the
+container-attribute-target+ resource meta-attribute allows the user to specify
which approach to use. If it is set to +host+, then user-defined node attributes
will be checked on the underlying host. If it is anything else, the local node
(in this case the bundle node) is used as usual.
This only applies to user-defined attributes; the cluster will always check the
local node for cluster-defined attributes such as +#uname+.
If +container-attribute-target+ is +host+, the cluster will pass additional
environment variables to the primitive's resource agent that allow it to set
node attributes appropriately: +CRM_meta_container_attribute_target+ (identical
to the meta-attribute value) and +CRM_meta_physical_host+ (the name of the
underlying host).
[NOTE]
====
When called by a resource agent, the `attrd_updater` and `crm_attribute`
commands will automatically check those environment variables and set
attributes appropriately.
====
=== Bundle Meta-Attributes ===
indexterm:[Resource,Bundle,Meta-attributes]
Any meta-attribute set on a bundle will be inherited by the bundle's
primitive and any resources implicitly created by Pacemaker for the bundle.
This includes options such as +priority+, +target-role+, and +is-managed+. See
<> for more information.
=== Limitations of Bundles ===
Restarting pacemaker while a bundle is unmanaged or the cluster is in
maintenance mode may cause the bundle to fail.
Bundles may not be explicitly cloned or included in groups. This includes the
bundle's primitive and any resources implicitly created by Pacemaker for the
bundle. (If +replicas+ is greater than 1, the bundle will behave like a clone
implicitly.)
Bundles do not have instance attributes, utilization attributes, or operations,
though a bundle's primitive may have them.
A bundle with a primitive can run on a Pacemaker Remote node only if the bundle
uses a distinct +control-port+.
diff --git a/doc/sphinx/Pacemaker_Explained/resources.rst b/doc/sphinx/Pacemaker_Explained/resources.rst
index 592e299121..7e89b4a7d6 100644
--- a/doc/sphinx/Pacemaker_Explained/resources.rst
+++ b/doc/sphinx/Pacemaker_Explained/resources.rst
@@ -1,980 +1,984 @@
.. _resource:
Cluster Resources
-----------------
.. Convert_to_RST:
[[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 ==
+.. _primitive-resource:
+
+Resource Properties
+###################
+
+.. Convert_to_RST:
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]
-------
-------
=====
.. _resource_options:
Resource Options
################
.. Convert_to_RST_2:
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:
placeholder
.. Convert_to_RST_3:
|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:
placeholder
.. Convert_to_RST_4:
|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.
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.
-------
=====
.. _operation:
Resource Operations
###################
.. Convert_to_RST_5:
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.
.. _operation_properties:
Operation Properties
____________________
.. Convert_to_RST_6:
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
a|Varies by action:
* +stop+: +fence+ if +stonith-enabled+ is true or +block+ otherwise
* +demote+: +on-fail+ of the +monitor+ action with +role+ set to +Master+, if
present, enabled, and configured to a value other than +demote+, or +restart+
otherwise
* all other actions: +restart+
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.
* +demote:+ Demote the resource, without a full restart. This is valid only for
+promote+ actions, and for +monitor+ actions with both a nonzero +interval+
and +role+ set to +Master+; for any other action, a configuration error will
be logged, and the default behavior will be used.
* +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]
|=========================================================
[NOTE]
====
When +on-fail+ is set to +demote+, recovery from failure by a successful demote
causes the cluster to recalculate whether and where a new instance should be
promoted. The node with the failure is eligible, so if master scores have not
changed, it will be promoted again.
There is no direct equivalent of +migration-threshold+ for the master role, but
the same effect can be achieved with a location constraint using a
<> with a node attribute expression for the resource's fail
count.
For example, to immediately ban the master role from a node with any failed
promote or master monitor:
[source,XML]
----
----
This example assumes that there is a promotable clone of the +my_primitive+
resource (note that the primitive name, not the clone name, is used in the
rule), and that there is a recurring 10-second-interval monitor configured for
the master role (fail count attributes specify the interval in milliseconds).
====
[[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 ''
----