diff options
Diffstat (limited to 'doc/sphinx/Pacemaker_Explained/resources.rst')
| -rw-r--r-- | doc/sphinx/Pacemaker_Explained/resources.rst | 424 |
1 files changed, 23 insertions, 401 deletions
diff --git a/doc/sphinx/Pacemaker_Explained/resources.rst b/doc/sphinx/Pacemaker_Explained/resources.rst index 3b7520f..a971c44 100644 --- a/doc/sphinx/Pacemaker_Explained/resources.rst +++ b/doc/sphinx/Pacemaker_Explained/resources.rst @@ -362,8 +362,8 @@ behave and can be easily set using the ``--meta`` option of the | | | all :ref:`colocation constraints | | | | <s-resource-colocation>` involving this resource, | | | | as well as the implicit colocation constraints | - | | | created if this resource is in a :ref:`group | - | | | <group-resources>`. For details, see | + | | | created if this resource is in a | + | | | :ref:`group <group-resources>`. For details, see | | | | :ref:`s-coloc-influence`. *(since 2.1.0)* | +----------------------------+----------------------------------+------------------------------------------------------+ | target-role | Started | .. index:: | @@ -375,31 +375,39 @@ behave and can be easily set using the ``--meta`` option of the | | | | | | | * ``Stopped:`` Force the resource to be stopped | | | | * ``Started:`` Allow the resource to be started | - | | | (and in the case of :ref:`promotable clone | - | | | resources <s-resource-promotable>`, promoted | - | | | if appropriate) | + | | | (and in the case of | + | | | :ref:`promotable <s-resource-promotable>` clone | + | | | resources, promoted if appropriate) | | | | * ``Unpromoted:`` Allow the resource to be started, | | | | but only in the unpromoted role if the resource is | | | | :ref:`promotable <s-resource-promotable>` | | | | * ``Promoted:`` Equivalent to ``Started`` | +----------------------------+----------------------------------+------------------------------------------------------+ - | is-managed | TRUE | .. index:: | + | is-managed | TRUE | .. _is_managed: | + | | | | + | | | .. index:: | | | | single: is-managed; resource option | | | | single: resource; option, is-managed | | | | | - | | | Is the cluster allowed to start and stop | - | | | the resource? Allowed values: ``true``, ``false`` | + | | | If false, the cluster will not start or stop the | + | | | resource on any node. Recurring actions for the | + | | | resource are unaffected. Maintenance mode overrides | + | | | this setting. Allowed values: ``true``, ``false`` | +----------------------------+----------------------------------+------------------------------------------------------+ - | maintenance | FALSE | .. index:: | + | maintenance | FALSE | .. _rsc_maintenance: | + | | | | + | | | .. index:: | | | | single: maintenance; resource option | | | | single: resource; option, maintenance | | | | | - | | | Similar to the ``maintenance-mode`` | - | | | :ref:`cluster option <cluster_options>`, 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`` | + | | | If true, the cluster will not start or stop the | + | | | resource on any node, and will pause any recurring | + | | | monitors (except those specifying ``role`` as | + | | | ``Stopped``). If true, the | + | | | :ref:`maintenance-mode <maintenance_mode>` cluster | + | | | option or :ref:`maintenance <node_maintenance>` | + | | | node attribute override this. Allowed values: | + | | | ``true``, ``false`` | +----------------------------+----------------------------------+------------------------------------------------------+ | resource-stickiness | 1 for individual clone | .. _resource-stickiness: | | | instances, 0 for all | | @@ -686,389 +694,3 @@ attributes, their purpose and default values. <action name="meta-data" timeout="5s" /> </actions> </resource-agent> - -.. index:: - single: resource; action - single: resource; operation - -.. _operation: - -Resource Operations -################### - -*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). - -.. topic:: An OCF resource with a non-default start timeout - - .. code-block:: xml - - <primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat"> - <operations> - <op id="Public-IP-start" name="start" timeout="60s"/> - </operations> - <instance_attributes id="params-public-ip"> - <nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/> - </instance_attributes> - </primitive> - -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 -____________________ - -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. - -.. table:: **Properties of an Operation** - :class: longtable - :widths: 1 2 3 - - +----------------+-----------------------------------+-----------------------------------------------------+ - | Field | Default | Description | - +================+===================================+=====================================================+ - | id | | .. index:: | - | | | single: id; action property | - | | | single: action; property, id | - | | | | - | | | A unique name for the operation. | - +----------------+-----------------------------------+-----------------------------------------------------+ - | name | | .. index:: | - | | | single: name; action property | - | | | single: action; property, name | - | | | | - | | | The action to perform. This can be any action | - | | | supported by the agent; common values include | - | | | ``monitor``, ``start``, and ``stop``. | - +----------------+-----------------------------------+-----------------------------------------------------+ - | interval | 0 | .. index:: | - | | | single: interval; action property | - | | | single: action; property, interval | - | | | | - | | | 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 | - | | | :ref:`monitor <s-resource-monitoring>`. | - +----------------+-----------------------------------+-----------------------------------------------------+ - | timeout | | .. index:: | - | | | single: timeout; action property | - | | | single: action; property, timeout | - | | | | - | | | How long to wait before declaring the action | - | | | has failed | - +----------------+-----------------------------------+-----------------------------------------------------+ - | on-fail | Varies by action: | .. index:: | - | | | single: on-fail; action property | - | | * ``stop``: ``fence`` if | single: action; property, on-fail | - | | ``stonith-enabled`` is true | | - | | or ``block`` otherwise | The action to take if this action ever fails. | - | | * ``demote``: ``on-fail`` of the | Allowed values: | - | | ``monitor`` action with | | - | | ``role`` set to ``Promoted``, | * ``ignore:`` Pretend the resource did not fail. | - | | if present, enabled, and | * ``block:`` Don't perform any further operations | - | | configured to a value other | on the resource. | - | | than ``demote``, or ``restart`` | * ``stop:`` Stop the resource and do not start | - | | otherwise | it elsewhere. | - | | * all other actions: ``restart`` | * ``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 | - | | | ``Promoted``; for any other action, a | - | | | configuration error will be logged, and the | - | | | default behavior will be used. *(since 2.0.5)* | - | | | * ``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. | - +----------------+-----------------------------------+-----------------------------------------------------+ - | enabled | TRUE | .. index:: | - | | | single: enabled; action property | - | | | single: action; property, enabled | - | | | | - | | | 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 :ref:`not block any configured monitoring | - | | | <s-monitoring-unmanaged>`. Disabling the operation | - | | | does not suppress all actions of the given type. | - | | | Allowed values: ``true``, ``false``. | - +----------------+-----------------------------------+-----------------------------------------------------+ - | record-pending | TRUE | .. index:: | - | | | single: record-pending; action property | - | | | single: action; property, record-pending | - | | | | - | | | 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 :ref:`s-operation-defaults`). Allowed values: | - | | | ``true``, ``false``. | - +----------------+-----------------------------------+-----------------------------------------------------+ - | role | | .. index:: | - | | | single: role; action property | - | | | single: action; property, 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 :ref:`promotable | - | | | clone resources <s-resource-promotable>`, | - | | | ``Unpromoted`` and ``Promoted``. | - +----------------+-----------------------------------+-----------------------------------------------------+ - -.. 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 promotion - scores have not changed, it will be promoted again. - - There is no direct equivalent of ``migration-threshold`` for the promoted - role, but the same effect can be achieved with a location constraint using a - :ref:`rule <rules>` with a node attribute expression for the resource's fail - count. - - For example, to immediately ban the promoted role from a node with any - failed promote or promoted instance monitor: - - .. code-block:: xml - - <rsc_location id="loc1" rsc="my_primitive"> - <rule id="rule1" score="-INFINITY" role="Promoted" boolean-op="or"> - <expression id="expr1" attribute="fail-count-my_primitive#promote_0" - operation="gte" value="1"/> - <expression id="expr2" attribute="fail-count-my_primitive#monitor_10000" - operation="gte" value="1"/> - </rule> - </rsc_location> - - 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 promoted 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 [#]_. You must configure ``monitor`` -operations explicitly to perform these checks. - -.. topic:: An OCF resource with a recurring health check - - .. code-block:: xml - - <primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat"> - <operations> - <op id="Public-IP-start" name="start" timeout="60s"/> - <op id="Public-IP-monitor" name="monitor" interval="60s"/> - </operations> - <instance_attributes id="params-public-ip"> - <nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/> - </instance_attributes> - </primitive> - -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 - :ref:`clone <s-resource-clone>` 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 resource is put into maintenance mode (by setting - ``maintenance=true``): The resource will be marked as unmanaged. (This - overrides ``is-managed=true``.) - - Additionally, all monitor operations will be stopped, except those specifying - ``role`` as ``Stopped`` (which will be newly initiated if appropriate). As - with unmanaged resources in general, starting a resource on a node other than - where the cluster expects it to be will cause problems. - -* 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 a node is put into maintenance mode: All resources that are active on the - node will be marked as in maintenance mode. See above for more details. - -* When the cluster is put into maintenance mode: All resources in the cluster - will be marked as in maintenance mode. See above for more details. - -A resource is in maintenance mode if the cluster, the node where the resource -is active, or the resource itself is configured to be in maintenance mode. If a -resource is in maintenance mode, then it is also unmanaged. However, if a -resource is unmanaged, it is not necessarily in maintenance mode. - -.. _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, - -.. code-block:: none - - # 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. - -.. topic:: An OCF resource with custom timeouts for its implicit actions - - .. code-block:: xml - - <primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat"> - <operations> - <op id="public-ip-startup" name="monitor" interval="0" timeout="90s"/> - <op id="public-ip-start" name="start" interval="0" timeout="180s"/> - <op id="public-ip-stop" name="stop" interval="0" timeout="15min"/> - </operations> - <instance_attributes id="params-public-ip"> - <nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/> - </instance_attributes> - </primitive> - -Multiple Monitor Operations -___________________________ - -Provided no two operations (for a single resource) have the same name -and interval, you can have as many ``monitor`` operations as you like. -In this way, you can do a superficial health check every minute and -progressively more intense ones at higher intervals. - -To tell the resource agent what kind of check to perform, you need to -provide each monitor with a different value for a common parameter. -The OCF standard creates a special parameter called ``OCF_CHECK_LEVEL`` -for this purpose and dictates that it is "made available to the -resource agent without the normal ``OCF_RESKEY`` prefix". - -Whatever name you choose, you can specify it by adding an -``instance_attributes`` block to the ``op`` tag. It is up to each -resource agent to look for the parameter and decide how to use it. - -.. topic:: An OCF resource with two recurring health checks, performing - different levels of checks specified via ``OCF_CHECK_LEVEL``. - - .. code-block:: xml - - <primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat"> - <operations> - <op id="public-ip-health-60" name="monitor" interval="60"> - <instance_attributes id="params-public-ip-depth-60"> - <nvpair id="public-ip-depth-60" name="OCF_CHECK_LEVEL" value="10"/> - </instance_attributes> - </op> - <op id="public-ip-health-300" name="monitor" interval="300"> - <instance_attributes id="params-public-ip-depth-300"> - <nvpair id="public-ip-depth-300" name="OCF_CHECK_LEVEL" value="20"/> - </instance_attributes> - </op> - </operations> - <instance_attributes id="params-public-ip"> - <nvpair id="public-ip-level" name="ip" value="192.0.2.2"/> - </instance_attributes> - </primitive> - -Disabling a Monitor Operation -_____________________________ - -The easiest way to stop a recurring monitor is to just delete it. -However, there can be times when you only want to disable it -temporarily. In such cases, simply add ``enabled=false`` to the -operation's definition. - -.. topic:: Example of an OCF resource with a disabled health check - - .. code-block:: xml - - <primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat"> - <operations> - <op id="public-ip-check" name="monitor" interval="60s" enabled="false"/> - </operations> - <instance_attributes id="params-public-ip"> - <nvpair id="public-ip-addr" name="ip" value="192.0.2.2"/> - </instance_attributes> - </primitive> - -This can be achieved from the command line by executing: - -.. code-block:: none - - # cibadmin --modify --xml-text '<op id="public-ip-check" enabled="false"/>' - -Once you've done whatever you needed to do, you can then re-enable it with - -.. code-block:: none - - # cibadmin --modify --xml-text '<op id="public-ip-check" enabled="true"/>' - -.. [#] Currently, anyway. Automatic monitoring operations may be added in a future - version of Pacemaker. |