diff --git a/doc/sphinx/Pacemaker_Administration/agents.rst b/doc/sphinx/Pacemaker_Administration/agents.rst index e65600e797..1f80aaa124 100644 --- a/doc/sphinx/Pacemaker_Administration/agents.rst +++ b/doc/sphinx/Pacemaker_Administration/agents.rst @@ -1,518 +1,928 @@ .. index:: single: resource agent Resource Agents --------------- Action Completion ################# If one resource depends on another resource via constraints, the cluster will interpret an expected result as sufficient to continue with dependent actions. This may cause timing issues if the resource agent start returns before the service is not only launched but fully ready to perform its function, or if the resource agent stop returns before the service has fully released all its claims on system resources. At a minimum, the start or stop should not return before a status command would return the expected (started or stopped) result. .. index:: single: OCF resource agent single: resource agent; OCF OCF Resource Agents ################### .. index:: single: OCF resource agent; location Location of Custom Scripts __________________________ OCF Resource Agents are found in ``/usr/lib/ocf/resource.d/$PROVIDER`` When creating your own agents, you are encouraged to create a new directory under ``/usr/lib/ocf/resource.d/`` so that they are not confused with (or overwritten by) the agents shipped by existing providers. So, for example, if you choose the provider name of big-corp and want a new resource named big-app, you would create a resource agent called ``/usr/lib/ocf/resource.d/big-corp/big-app`` and define a resource: .. code-block: xml .. index:: single: OCF resource agent; action Actions _______ All OCF resource agents are required to implement the following actions. .. list-table:: **Required Actions for OCF Agents** :class: longtable :widths: 1 4 3 :header-rows: 1 * - Action - Description - Instructions * - .. _start_action: .. index:: single: OCF resource agent; start single: start action start - Start the resource - Return :ref:`OCF_SUCCESS ` on success and an appropriate error code otherwise. Must not report success until the resource is fully active. * - .. _stop_action: .. index:: single: OCF resource agent; stop single: stop action stop - Stop the resource - Return :ref:`OCF_SUCCESS ` on success and an appropriate error code otherwise. Must not report success until the resource is fully stopped. * - .. _monitor_action: .. index:: single: OCF resource agent; monitor single: monitor action monitor - Check the resource's state - Return :ref:`OCF_SUCCESS ` if the resource is running, :ref:`OCF_NOT_RUNNING ` if it is stopped, and any other :ref:`OCF exit code ` if it is failed. **Note:** The monitor action should test the state of the resource on the local machine only. * - .. _meta_data_action: .. index:: single: OCF resource agent; meta-data single: meta-data action meta-data - Describe the resource - Provide information about this resource in the XML format defined by the OCF standard. Return :ref:`OCF_SUCCESS `. **Note:** This is *not* required to be performed as root. OCF resource agents may optionally implement additional actions. Some are used only with advanced resource types such as clones. .. list-table:: **Optional Actions for OCF Resource Agents** :class: longtable: :widths: 1 4 3 :header-rows: 1 * - Action - Description - Instructions * - .. _validate_all_action: .. index:: single: OCF resource agent; validate-all single: validate-all action validate-all - Validate the instance parameters provided. - Return :ref:`OCF_SUCCESS ` if parameters are valid, :ref:`OCF_ERR_ARGS ` if not valid, and :ref:`OCF_ERR_CONFIGURED ` if resource is not configured. * - .. _promote_action: .. index:: single: OCF resource agent; promote single: promote action promote - Bring the local instance of a promotable clone resource to the promoted role. - Return :ref:`OCF_SUCCESS ` on success. * - .. _demote_action: .. index:: single: OCF resource agent; demote single: demote action demote - Bring the local instance of a promotable clone resource to the unpromoted role. - Return :ref:`OCF_SUCCESS ` on success. * - .. _notify_action: .. index:: single: OCF resource agent; notify single: notify action notify - Used by the cluster to send the agent pre- and post-notification events telling the resource what has happened and what will happen. - Must not fail. Must return :ref:`OCF_SUCCESS `. * - .. _reload_action: .. index:: single: OCF resource agent; reload single: reload action reload - Reload the service's own configuration. - Not used by Pacemaker. * - .. _reload_agent_action: .. index:: single: OCF resource agent; reload-agent single: reload-agent action reload-agent - Make effective any changes in instance parameters marked as reloadable in the agent's meta-data. - This is used when the agent can handle a change in some of its parameters more efficiently than stopping and starting the resource. * - .. _recover_action: .. index:: single: OCF resource agent; recover single: recover action recover - Restart the service. - Not used by Pacemaker. .. important:: If you create a new OCF resource agent, use `ocf-tester` to verify that the agent complies with the OCF standard properly. .. index:: single: OCF resource agent; return code How Are OCF Return Codes Interpreted? _____________________________________ The first thing the cluster does is to check the return code against the expected result. If the result does not match the expected value, then the operation is considered to have failed, and recovery action is initiated. There are three types of failure recovery: .. list-table:: **Types of Recovery Performed by the Cluster** :class: longtable :widths: 1 5 5 :header-rows: 1 * - Type - Description - Action Taken by the Cluster * - .. _soft_error: .. index:: single: OCF resource agent; soft error soft - A transient error - Restart the resource or move it to a new location * - .. _hard_error: .. index:: single: OCF resource agent; hard error hard - A non-transient error that may be specific to the current node - Move the resource elsewhere and prevent it from being retried on the current node * - .. _fatal_error: .. index:: single: OCF resource agent; fatal error fatal - A non-transient error that will be common to all cluster nodes (for example, a bad configuration was specified) - Stop the resource and prevent it from being started on any cluster node .. _ocf_return_codes: OCF Return Codes ________________ The following table outlines the various OCF return codes and the type of recovery the cluster will initiate when a failure code is received. Although counterintuitive, even actions that return ``OCF_SUCCESS`` can be considered to have failed, if ``OCF_SUCCESS`` was not the expected return value. .. list-table:: **OCF Exit Codes and Their Recovery Types** :class: longtable :widths: 1 3 6 2 :header-rows: 1 * - Exit Code - OCF Alias - Description - Recovery * - .. _OCF_SUCCESS: .. index:: single: OCF_SUCCESS single: OCF return code; OCF_SUCCESS pair: OCF return code; 0 0 - OCF_SUCCESS - Success. The command completed successfully. This is the expected result for all start, stop, promote, and demote actions. - :ref:`soft ` * - .. _OCF_ERR_GENERIC: .. index:: single: OCF_ERR_GENERIC single: OCF return code; OCF_ERR_GENERIC pair: OCF return code; 1 1 - OCF_ERR_GENERIC - Generic "there was a problem" error code. - :ref:`hard ` * - .. _OCF_ERR_ARGS: .. index:: single: OCF_ERR_ARGS single: OCF return code; OCF_ERR_ARGS pair: OCF return code; 2 2 - OCF_ERR_ARGS - The resource's parameter values are not valid on this machine (for example, a value refers to a file not found on the local host). - :ref:`hard ` * - .. _OCF_ERR_UNIMPLEMENTED: .. index:: single: OCF_ERR_UNIMPLEMENTED single: OCF return code; OCF_ERR_UNIMPLEMENTED pair: OCF return code; 3 3 - OCF_ERR_UNIMPLEMENTED - The requested action is not implemented. - :ref:`hard ` * - .. _OCF_ERR_PERM: .. index:: single: OCF_ERR_PERM single: OCF return code; OCF_ERR_PERM pair: OCF return code; 4 4 - OCF_ERR_PERM - The resource agent does not have sufficient privileges to complete the task. - :ref:`hard ` * - .. _OCF_ERR_INSTALLED: .. index:: single: OCF_ERR_INSTALLED single: OCF return code; OCF_ERR_INSTALLED pair: OCF return code; 5 5 - OCF_ERR_INSTALLED - The tools required by the resource are not installed on this machine. - :ref:`hard ` * - .. _OCF_ERR_CONFIGURED: .. index:: single: OCF_ERR_CONFIGURED single: OCF return code; OCF_ERR_CONFIGURED pair: OCF return code; 6 6 - OCF_ERR_CONFIGURED - The resource's parameter values are inherently invalid (for example, a required parameter was not given). - :ref:`fatal ` * - .. _OCF_NOT_RUNNING: .. index:: single: OCF_NOT_RUNNING single: OCF return code; OCF_NOT_RUNNING pair: OCF return code; 7 7 - OCF_NOT_RUNNING - The resource is safely stopped. This should only be returned by monitor actions, not stop actions. - N/A * - .. _OCF_RUNNING_PROMOTED: .. index:: single: OCF_RUNNING_PROMOTED single: OCF return code; OCF_RUNNING_PROMOTED pair: OCF return code; 8 8 - OCF_RUNNING_PROMOTED - The resource is running in the promoted role. - :ref:`soft ` * - .. _OCF_FAILED_PROMOTED: .. index:: single: OCF_FAILED_PROMOTED single: OCF return code; OCF_FAILED_PROMOTED pair: OCF return code; 9 9 - OCF_FAILED_PROMOTED - The resource is (or might be) in the promoted role but has failed. The resource will be demoted, stopped, and then started (and possibly promoted) again. - :ref:`soft ` * - .. _OCF_DEGRADED: .. index:: single: OCF_DEGRADED single: OCF return code; OCF_DEGRADED pair: OCF return code; 190 190 - OCF_DEGRADED - The resource is properly active, but in such a condition that future failures are more likely. - none * - .. _OCF_DEGRADED_PROMOTED: .. index:: single: OCF_DEGRADED_PROMOTED single: OCF return code; OCF_DEGRADED_PROMOTED pair: OCF return code; 191 191 - OCF_DEGRADED_PROMOTED - The resource is properly active in the promoted role, but in such a condition that future failures are more likely. - none * - other - *none* - Custom error code. - soft Exceptions to the recovery handling described above: * Probes (non-recurring monitor actions) that find a resource active (or in the promoted role) will not result in recovery action unless it is also found active elsewhere. * The recovery action taken when a resource is found active more than once is determined by the resource's ``multiple-active`` property. * Recurring actions that return ``OCF_ERR_UNIMPLEMENTED`` do not cause any type of recovery. * Actions that return one of the "degraded" codes will be treated the same as if they had returned success, but status output will indicate that the resource is degraded. +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 respond with ``OCF_SUCCESS`` only 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 (for example, ``apache:2``). + +A resource agent 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 is not always an unbroken sequence, nor +does it 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 +begin in the unpromoted role. From there, the cluster will decide which +instances to promote. + +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. + +.. list-table:: **Role Implications of OCF Return Codes** + :class: longtable + :widths: 1 3 + :header-rows: 1 + + * - Monitor Return Code + - Description + * - :ref:`OCF_NOT_RUNNING ` + - .. index:: + single: OCF_NOT_RUNNING + single: OCF return code; OCF_NOT_RUNNING + + Stopped + * - :ref:`OCF_SUCCESS ` + - .. index:: + single: OCF_SUCCESS + single: OCF return code; OCF_SUCCESS + + Running (Unpromoted) + * - :ref:`OCF_RUNNING_PROMOTED ` + - .. index:: + single: OCF_RUNNING_PROMOTED + single: OCF return code; OCF_RUNNING_PROMOTED + + Running (Promoted) + * - :ref:`OCF_FAILED_PROMOTED ` + - .. index:: + single: OCF_FAILED_PROMOTED + single: OCF return code; OCF_FAILED_PROMOTED + + Failed (Promoted) + * - Other + - Failed (Unpromoted) + +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. These variables, when combined +with additional context, can be used to calculate the current state of the +cluster and what is about to happen to it. + +.. index:: + single: clone; environment variables + single: notify; environment variables + +.. list-table:: **Environment Variables Supplied with Clone Notify Actions** + :class: longtable + :widths: 1 1 + :header-rows: 1 + + * - Variable + - Description + * - .. _OCF_RESKEY_CRM_meta_notify_type: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_type + single: OCF_RESKEY_CRM_meta_notify_type + + OCF_RESKEY_CRM_meta_notify_type + - Allowed values: ``pre``, ``post`` + * - .. _OCF_RESKEY_CRM_meta_notify_operation: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_operation + single: OCF_RESKEY_CRM_meta_notify_operation + + OCF_RESKEY_CRM_meta_notify_operation + - Allowed values: ``start``, ``stop`` + * - .. _OCF_RESKEY_CRM_meta_notify_start_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_start_resource + single: OCF_RESKEY_CRM_meta_notify_start_resource + + OCF_RESKEY_CRM_meta_notify_start_resource + - Resources to be started + * - .. _OCF_RESKEY_CRM_meta_notify_stop_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_stop_resource + single: OCF_RESKEY_CRM_meta_notify_stop_resource + + OCF_RESKEY_CRM_meta_notify_stop_resource + - Resources to be stopped + * - .. _OCF_RESKEY_CRM_meta_notify_active_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_active_resource + single: OCF_RESKEY_CRM_meta_notify_active_resource + + OCF_RESKEY_CRM_meta_notify_active_resource + - Resources that are running + * - .. _OCF_RESKEY_CRM_meta_notify_inactive_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_inactive_resource + single: OCF_RESKEY_CRM_meta_notify_inactive_resource + + OCF_RESKEY_CRM_meta_notify_inactive_resource + - Resources that are not running + * - .. _OCF_RESKEY_CRM_meta_notify_start_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_start_uname + single: OCF_RESKEY_CRM_meta_notify_start_uname + + OCF_RESKEY_CRM_meta_notify_start_uname + - Nodes on which resources will be started + * - .. _OCF_RESKEY_CRM_meta_notify_stop_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_stop_uname + single: OCF_RESKEY_CRM_meta_notify_stop_uname + + OCF_RESKEY_CRM_meta_notify_stop_uname + - Nodes on which resources will be stopped + * - .. _OCF_RESKEY_CRM_meta_notify_active_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_active_uname + single: OCF_RESKEY_CRM_meta_notify_active_uname + + OCF_RESKEY_CRM_meta_notify_active_uname + - Nodes on which resources are running + +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: + +.. topic:: Notification Variables + + .. code-block:: none + + 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 +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. index:: + single: clone; environment variables + single: promotable; environment variables + +.. list-table:: **Extra Environment Variables Supplied for Promotable Clones** + :class: longtable + :widths: 1 1 + :header-rows: 1 + + * - Variable + - Description + * - .. _OCF_RESKEY_CRM_meta_notify_promoted_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_promoted_resource + single: OCF_RESKEY_CRM_meta_notify_promoted_resource + + OCF_RESKEY_CRM_meta_notify_promoted_resource + - Resources that are running in the promoted role + * - .. _OCF_RESKEY_CRM_meta_notify_unpromoted_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_unpromoted_resource + single: OCF_RESKEY_CRM_meta_notify_unpromoted_resource + + OCF_RESKEY_CRM_meta_notify_unpromoted_resource + - Resources that are running in the unpromoted role + * - .. _OCF_RESKEY_CRM_meta_notify_promote_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_promote_resource + single: OCF_RESKEY_CRM_meta_notify_promote_resource + + OCF_RESKEY_CRM_meta_notify_promote_resource + - Resources to be promoted + * - .. _OCF_RESKEY_CRM_meta_notify_demote_resource: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_demote_resource + single: OCF_RESKEY_CRM_meta_notify_demote_resource + + OCF_RESKEY_CRM_meta_notify_demote_resource + - Resources to be demoted + * - .. _OCF_RESKEY_CRM_meta_notify_promote_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_promote_uname + single: OCF_RESKEY_CRM_meta_notify_promote_uname + + OCF_RESKEY_CRM_meta_notify_promote_uname + - Nodes on which resources will be promoted + * - .. _OCF_RESKEY_CRM_meta_notify_demote_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_demote_uname + single: OCF_RESKEY_CRM_meta_notify_demote_uname + + OCF_RESKEY_CRM_meta_notify_demote_uname + - Nodes on which resources will be demoted + * - .. _OCF_RESKEY_CRM_meta_notify_promoted_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_promoted_uname + single: OCF_RESKEY_CRM_meta_notify_promoted_uname + + OCF_RESKEY_CRM_meta_notify_promoted_uname + - Nodes on which resources are running in the promoted role + * - .. _OCF_RESKEY_CRM_meta_notify_unpromoted_uname: + + .. index:: + single: environment variable; OCF_RESKEY_CRM_meta_notify_unpromoted_uname + single: OCF_RESKEY_CRM_meta_notify_unpromoted_uname + + OCF_RESKEY_CRM_meta_notify_unpromoted_uname + - Nodes on which resources are running in the unpromoted role + +Interpretation of Promotable Notification Variables +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +**Pre-notification (demote):** + +* Active resources: ``$OCF_RESKEY_CRM_meta_notify_active_resource`` +* Promoted resources: ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` +* Unpromoted resources: ``$OCF_RESKEY_CRM_meta_notify_unpromoted_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`` +* Promoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` + * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` +* Unpromoted resources: ``$OCF_RESKEY_CRM_meta_notify_unpromoted_resource`` +* Inactive resources: ``$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 ``$OCF_RESKEY_CRM_meta_notify_stop_resource`` +* Promoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` + * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` +* Unpromoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_unpromoted_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`` +* Promoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` + * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` +* Unpromoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_unpromoted_resource`` + * minus ``$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`` +* Promoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` + * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` + * plus ``$OCF_RESKEY_CRM_meta_notify_promote_resource`` +* Unpromoted resources: + * ``$OCF_RESKEY_CRM_meta_notify_unpromoted_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`` + .. index:: single: resource agent; LSB single: LSB resource agent single: init script LSB Resource Agents (Init Scripts) ################################## LSB Compliance ______________ The relevant part of the `LSB specifications `_ includes a description of all the return codes listed here. Assuming `some_service` is configured correctly and currently inactive, the following sequence will help you determine if it is LSB-compatible: #. Start (stopped): .. code-block:: none # /etc/init.d/some_service start ; echo "result: $?" * Did the service start? * Did the echo command print ``result: 0`` (in addition to the init script's usual output)? #. Status (running): .. code-block:: none # /etc/init.d/some_service status ; echo "result: $?" * Did the script accept the command? * Did the script indicate the service was running? * Did the echo command print ``result: 0`` (in addition to the init script's usual output)? #. Start (running): .. code-block:: none # /etc/init.d/some_service start ; echo "result: $?" * Is the service still running? * Did the echo command print ``result: 0`` (in addition to the init script's usual output)? #. Stop (running): .. code-block:: none # /etc/init.d/some_service stop ; echo "result: $?" * Was the service stopped? * Did the echo command print ``result: 0`` (in addition to the init script's usual output)? #. Status (stopped): .. code-block:: none # /etc/init.d/some_service status ; echo "result: $?" * Did the script accept the command? * Did the script indicate the service was not running? * Did the echo command print ``result: 3`` (in addition to the init script's usual output)? #. Stop (stopped): .. code-block:: none # /etc/init.d/some_service stop ; echo "result: $?" * Is the service still stopped? * Did the echo command print ``result: 0`` (in addition to the init script's usual output)? #. Status (failed): This step is not readily testable and relies on manual inspection of the script. The script can use one of the error codes (other than 3) listed in the LSB spec to indicate that it is active but failed. This tells the cluster that before moving the resource to another node, it needs to stop it on the existing one first. If the answer to any of the above questions is no, then the script is not LSB-compliant. Your options are then to either fix the script or write an OCF agent based on the existing script. diff --git a/doc/sphinx/Pacemaker_Explained/collective.rst b/doc/sphinx/Pacemaker_Explained/collective.rst index a4fa9dc65b..dc6832c061 100644 --- a/doc/sphinx/Pacemaker_Explained/collective.rst +++ b/doc/sphinx/Pacemaker_Explained/collective.rst @@ -1,1637 +1,1226 @@ .. index: single: collective resource single: resource; collective Collective Resources -------------------- Pacemaker supports several types of *collective* resources, which consist of multiple, related resource instances. .. index: single: group resource single: resource; group .. _group-resources: Groups - A Syntactic Shortcut ############################# 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. .. topic:: A group of two primitive resources .. code-block:: 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: .. topic:: How the cluster sees a group resource .. code-block:: 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. .. index:: pair: XML element; group Group Properties ________________ .. table:: **Properties of a Group Resource** :widths: 1 4 +-------------+------------------------------------------------------------------+ | Field | Description | +=============+==================================================================+ | id | .. index:: | | | single: group; property, id | | | single: property; id (group) | | | single: id; group property | | | | | | A unique name for the group | +-------------+------------------------------------------------------------------+ | description | .. index:: | | | single: group; attribute, description | | | single: attribute; description (group) | | | single: description; group attribute | | | | | | An optional description of the group, for the user's own | | | purposes. | | | E.g. ``resources needed for website`` | +-------------+------------------------------------------------------------------+ Group Options _____________ Groups inherit the ``priority``, ``target-role``, and ``is-managed`` properties from primitive resources. See :ref:`resource_options` for information about those properties. Group Instance Attributes _________________________ Groups have no instance attributes. However, any that are set for the group object will be inherited by the group's children. Group Contents ______________ Groups may only contain a collection of cluster resources (see :ref:`primitive-resource`). To refer to a child of a group resource, just use the child's ``id`` instead of the group's. Group Constraints _________________ Although it is possible to reference a group's children in constraints, it is usually preferable to reference the group itself. .. topic:: Some constraints involving groups .. code-block:: xml .. index:: pair: resource-stickiness; group Group Stickiness ________________ 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. .. index:: single: clone single: resource; clone .. _s-resource-clone: Clones - Resources That Can Have Multiple Active Instances ########################################################## *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 [#]_. 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. .. index:: single: promotable clone single: resource; promotable .. _s-resource-promotable: Promotable clones _________________ 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 *promoted* and *unpromoted* to be agnostic to what the service calls them or what they do. All that Pacemaker cares about is that an instance comes up in the unpromoted role when started, and the resource agent supports the ``promote`` and ``demote`` actions to manage entering and exiting the promoted role. .. index:: pair: XML element; clone Clone Properties ________________ .. table:: **Properties of a Clone Resource** :widths: 1 4 +-------------+------------------------------------------------------------------+ | Field | Description | +=============+==================================================================+ | id | .. index:: | | | single: clone; property, id | | | single: property; id (clone) | | | single: id; clone property | | | | | | A unique name for the clone | +-------------+------------------------------------------------------------------+ | description | .. index:: | | | single: clone; attribute, description | | | single: attribute; description (clone) | | | single: description; clone attribute | | | | | | An optional description of the clone, for the user's own | | | purposes. | | | E.g. ``IP address for website`` | +-------------+------------------------------------------------------------------+ .. index:: pair: options; clone Clone Options _____________ :ref:`Options ` inherited from primitive resources: ``priority, target-role, is-managed`` .. table:: **Clone-specific configuration options** :class: longtable :widths: 1 1 3 +-------------------+-----------------+-------------------------------------------------------+ | Field | Default | Description | +===================+=================+=======================================================+ | globally-unique | false | .. index:: | | | | single: clone; option, globally-unique | | | | single: option; globally-unique (clone) | | | | single: globally-unique; clone option | | | | | | | | If **true**, each clone instance performs a | | | | distinct function | +-------------------+-----------------+-------------------------------------------------------+ | clone-max | 0 | .. index:: | | | | single: clone; option, clone-max | | | | single: option; clone-max (clone) | | | | single: clone-max; clone option | | | | | | | | The maximum number of clone instances that can | | | | be started across the entire cluster. If 0, the | | | | number of nodes in the cluster will be used. | +-------------------+-----------------+-------------------------------------------------------+ | clone-node-max | 1 | .. index:: | | | | single: clone; option, clone-node-max | | | | single: option; clone-node-max (clone) | | | | single: clone-node-max; clone option | | | | | | | | If ``globally-unique`` is **true**, the maximum | | | | number of clone instances that can be started | | | | on a single node | +-------------------+-----------------+-------------------------------------------------------+ | clone-min | 0 | .. index:: | | | | single: clone; option, clone-min | | | | single: option; clone-min (clone) | | | | single: clone-min; clone option | | | | | | | | 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. | +-------------------+-----------------+-------------------------------------------------------+ | notify | false | .. index:: | | | | single: clone; option, notify | | | | single: option; notify (clone) | | | | single: notify; clone option | | | | | | | | 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** | +-------------------+-----------------+-------------------------------------------------------+ | ordered | false | .. index:: | | | | single: clone; option, ordered | | | | single: option; ordered (clone) | | | | single: ordered; clone option | | | | | | | | If **true**, clone instances must be started | | | | sequentially instead of in parallel. | | | | Allowed values: **false**, **true** | +-------------------+-----------------+-------------------------------------------------------+ | interleave | false | .. index:: | | | | single: clone; option, interleave | | | | single: option; interleave (clone) | | | | single: interleave; clone option | | | | | | | | 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** | +-------------------+-----------------+-------------------------------------------------------+ | promotable | false | .. index:: | | | | single: clone; option, promotable | | | | single: option; promotable (clone) | | | | single: promotable; clone option | | | | | | | | 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** | +-------------------+-----------------+-------------------------------------------------------+ | promoted-max | 1 | .. index:: | | | | single: clone; option, promoted-max | | | | single: option; promoted-max (clone) | | | | single: promoted-max; clone option | | | | | | | | If ``promotable`` is **true**, the number of | | | | instances that can be promoted at one time | | | | across the entire cluster | +-------------------+-----------------+-------------------------------------------------------+ | promoted-node-max | 1 | .. index:: | | | | single: clone; option, promoted-node-max | | | | single: option; promoted-node-max (clone) | | | | single: promoted-node-max; clone option | | | | | | | | If ``promotable`` is **true** and ``globally-unique`` | | | | is **false**, the number of clone instances can be | | | | promoted at one time on a single node | +-------------------+-----------------+-------------------------------------------------------+ .. note:: **Deprecated Terminology** In older documentation and online examples, you may see promotable clones referred to as *multi-state*, *stateful*, or *master/slave*; these mean the same thing as *promotable*. Certain syntax is supported for backward compatibility, but is deprecated and will be removed in a future version: * Using a ``master`` tag, instead of a ``clone`` tag with the ``promotable`` meta-attribute set to ``true`` * Using the ``master-max`` meta-attribute instead of ``promoted-max`` * Using the ``master-node-max`` meta-attribute instead of ``promoted-node-max`` * Using ``Master`` as a role name instead of ``Promoted`` * Using ``Slave`` as a role name instead of ``Unpromoted`` Clone Contents ______________ Clones must contain exactly one primitive or group resource. .. topic:: A clone that runs a web server on all nodes .. code-block:: 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 Attribute ________________________ Clones have no instance attributes; however, any that are set here will be inherited by the clone's child. .. index:: single: clone; constraint 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. .. topic:: Some constraints involving clones .. code-block:: 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. .. index:: single: promotable clone; constraint .. _promotable-clone-constraints: 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 promoted role, and colocation constraints may contain ``rsc-role`` and/or ``with-rsc-role`` fields. .. topic:: Constraints involving promotable clone resources .. code-block:: xml In the example above, **myApp** will wait until one of the database copies has been started and promoted 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 (``Promoted`` or ``Unpromoted``). In the example above, the cluster will choose a location based on where database is running in the promoted role, and if there are multiple promoted 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When a promotable clone is used in a :ref:`resource set ` inside a colocation constraint, the resource set may take a ``role`` attribute. In the following example, an instance of **B** may be promoted only on a node where **A** is in the promoted role. Additionally, resources **C** and **D** must be located on a node where both **A** and **B** are promoted. .. topic:: Colocate C and D with A's and B's promoted instances .. code-block:: xml Using Promotable Clone Resources in Ordered Sets ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When a promotable clone is used in a :ref:`resource set ` inside an ordering constraint, the resource set may take an ``action`` attribute. .. topic:: Start C and D after first promoting A and B .. code-block:: xml In the above example, **B** cannot be promoted until **A** has been promoted. Additionally, resources **C** and **D** must wait until **A** and **B** have been promoted before they can start. .. index:: pair: resource-stickiness; clone .. _s-clone-stickiness: Clone Stickiness ________________ To achieve stable assignments, 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 instances 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 unpromoted role. From there, the -cluster will decide which instances to promote. - -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. - -.. table:: **Role implications of OCF return codes** - :widths: 1 3 - - +----------------------+--------------------------------------------------+ - | Monitor Return Code | Description | - +======================+==================================================+ - | OCF_NOT_RUNNING | .. index:: | - | | single: OCF_NOT_RUNNING | - | | single: OCF return code; OCF_NOT_RUNNING | - | | | - | | Stopped | - +----------------------+--------------------------------------------------+ - | OCF_SUCCESS | .. index:: | - | | single: OCF_SUCCESS | - | | single: OCF return code; OCF_SUCCESS | - | | | - | | Running (Unpromoted) | - +----------------------+--------------------------------------------------+ - | OCF_RUNNING_PROMOTED | .. index:: | - | | single: OCF_RUNNING_PROMOTED | - | | single: OCF return code; OCF_RUNNING_PROMOTED | - | | | - | | Running (Promoted) | - +----------------------+--------------------------------------------------+ - | OCF_FAILED_PROMOTED | .. index:: | - | | single: OCF_FAILED_PROMOTED | - | | single: OCF return code; OCF_FAILED_PROMOTED | - | | | - | | Failed (Promoted) | - +----------------------+--------------------------------------------------+ - | Other | .. index:: | - | | single: return code | - | | | - | | Failed (Unpromoted) | - +----------------------+--------------------------------------------------+ - -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. - -.. index:: - single: clone; environment variables - single: notify; environment variables - -.. table:: **Environment variables supplied with Clone notify actions** - :widths: 1 1 - - +----------------------------------------------+-------------------------------------------------------------------------------+ - | Variable | Description | - +==============================================+===============================================================================+ - | OCF_RESKEY_CRM_meta_notify_type | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_type | - | | single: OCF_RESKEY_CRM_meta_notify_type | - | | | - | | Allowed values: **pre**, **post** | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_operation | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_operation | - | | single: OCF_RESKEY_CRM_meta_notify_operation | - | | | - | | Allowed values: **start**, **stop** | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_start_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_start_resource | - | | single: OCF_RESKEY_CRM_meta_notify_start_resource | - | | | - | | Resources to be started | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_stop_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_stop_resource | - | | single: OCF_RESKEY_CRM_meta_notify_stop_resource | - | | | - | | Resources to be stopped | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_active_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_active_resource | - | | single: OCF_RESKEY_CRM_meta_notify_active_resource | - | | | - | | Resources that are running | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_inactive_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_inactive_resource | - | | single: OCF_RESKEY_CRM_meta_notify_inactive_resource | - | | | - | | Resources that are not running | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_start_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_start_uname | - | | single: OCF_RESKEY_CRM_meta_notify_start_uname | - | | | - | | Nodes on which resources will be started | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_stop_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_stop_uname | - | | single: OCF_RESKEY_CRM_meta_notify_stop_uname | - | | | - | | Nodes on which resources will be stopped | - +----------------------------------------------+-------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_active_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_active_uname | - | | single: OCF_RESKEY_CRM_meta_notify_active_uname | - | | | - | | Nodes on which resources are running | - +----------------------------------------------+-------------------------------------------------------------------------------+ - -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: - -.. topic:: Notification variables - - .. code-block:: none - - 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 -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -.. index:: - single: clone; environment variables - single: promotable; environment variables - -.. table:: **Extra environment variables supplied for promotable clones** - :widths: 1 1 - - +------------------------------------------------+---------------------------------------------------------------------------------+ - | Variable | Description | - +================================================+=================================================================================+ - | OCF_RESKEY_CRM_meta_notify_promoted_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_promoted_resource | - | | single: OCF_RESKEY_CRM_meta_notify_promoted_resource | - | | | - | | Resources that are running in the promoted role | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_unpromoted_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_unpromoted_resource | - | | single: OCF_RESKEY_CRM_meta_notify_unpromoted_resource | - | | | - | | Resources that are running in the unpromoted role | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_promote_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_promote_resource | - | | single: OCF_RESKEY_CRM_meta_notify_promote_resource | - | | | - | | Resources to be promoted | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_demote_resource | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_demote_resource | - | | single: OCF_RESKEY_CRM_meta_notify_demote_resource | - | | | - | | Resources to be demoted | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_promote_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_promote_uname | - | | single: OCF_RESKEY_CRM_meta_notify_promote_uname | - | | | - | | Nodes on which resources will be promoted | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_demote_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_demote_uname | - | | single: OCF_RESKEY_CRM_meta_notify_demote_uname | - | | | - | | Nodes on which resources will be demoted | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_promoted_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_promoted_uname | - | | single: OCF_RESKEY_CRM_meta_notify_promoted_uname | - | | | - | | Nodes on which resources are running in the promoted role | - +------------------------------------------------+---------------------------------------------------------------------------------+ - | OCF_RESKEY_CRM_meta_notify_unpromoted_uname | .. index:: | - | | single: environment variable; OCF_RESKEY_CRM_meta_notify_unpromoted_uname | - | | single: OCF_RESKEY_CRM_meta_notify_unpromoted_uname | - | | | - | | Nodes on which resources are running in the unpromoted role | - +------------------------------------------------+---------------------------------------------------------------------------------+ - -Interpretation of Promotable Notification Variables -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -**Pre-notification (demote):** - -* Active resources: ``$OCF_RESKEY_CRM_meta_notify_active_resource`` -* Promoted resources: ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` -* Unpromoted resources: ``$OCF_RESKEY_CRM_meta_notify_unpromoted_resource`` -* Inactive resources: ``$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: ``$OCF_RESKEY_CRM_meta_notify_active_resource`` -* Promoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` - * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` - -* Unpromoted resources: ``$OCF_RESKEY_CRM_meta_notify_unpromoted_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`` - -* Promoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` - * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` - -* Unpromoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_unpromoted_resource`` - * minus ``$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 ``$OCF_RESKEY_CRM_meta_notify_start_resource`` - -* Promoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` - * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` - -* Unpromoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_unpromoted_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 ``$OCF_RESKEY_CRM_meta_notify_start_resource`` - -* Promoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_promoted_resource`` - * minus ``$OCF_RESKEY_CRM_meta_notify_demote_resource`` - * plus ``$OCF_RESKEY_CRM_meta_notify_promote_resource`` - -* Unpromoted resources: - - * ``$OCF_RESKEY_CRM_meta_notify_unpromoted_resource`` - * minus ``$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 unpromoted role, and an additional one with ``role="Promoted"`` will cover the promoted role. .. topic:: Monitoring both states of a promotable clone resource .. code-block:: 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_attribute`` command using the ``--promotion`` option, 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 to be promoted. .. topic:: Explicitly preferring node1 to be promoted .. code-block:: xml .. index: single: bundle single: resource; bundle pair: container; Docker pair: container; podman pair: container; rkt .. _s-resource-bundle: Bundles - Containerized Resources ################################# Pacemaker supports a special syntax for launching a service inside a `container `_ with any infrastructure it requires: the *bundle*. Pacemaker bundles support `Docker `_, `podman `_ *(since 2.0.1)*, and `rkt `_ container technologies. [#]_ .. topic:: A bundle for a containerized web server .. code-block:: xml 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. .. index:: pair: XML element; bundle Bundle Properties _________________ .. table:: **XML Attributes of a bundle Element** :widths: 1 4 +-------------+------------------------------------------------------------------+ | Field | Description | +=============+==================================================================+ | id | .. index:: | | | single: bundle; attribute, id | | | single: attribute; id (bundle) | | | single: id; bundle attribute | | | | | | A unique name for the bundle (required) | +-------------+------------------------------------------------------------------+ | description | .. index:: | | | single: bundle; attribute, description | | | single: attribute; description (bundle) | | | single: description; bundle attribute | | | | | | An optional description of the group, for the user's own | | | purposes. | | | E.g. ``manages the container that runs the service`` | +-------------+------------------------------------------------------------------+ A bundle must contain exactly one ``docker``, ``podman``, or ``rkt`` element. .. index:: pair: XML element; docker pair: XML element; podman pair: XML element; rkt Bundle Container Properties ___________________________ .. table:: **XML attributes of a docker, podman, or rkt Element** :class: longtable :widths: 2 3 4 +-------------------+------------------------------------+---------------------------------------------------+ | Attribute | Default | Description | +===================+====================================+===================================================+ | image | | .. index:: | | | | single: docker; attribute, image | | | | single: attribute; image (docker) | | | | single: image; docker attribute | | | | single: podman; attribute, image | | | | single: attribute; image (podman) | | | | single: image; podman attribute | | | | single: rkt; attribute, image | | | | single: attribute; image (rkt) | | | | single: image; rkt attribute | | | | | | | | Container image tag (required) | +-------------------+------------------------------------+---------------------------------------------------+ | replicas | Value of ``promoted-max`` | .. index:: | | | if that is positive, else 1 | single: docker; attribute, replicas | | | | single: attribute; replicas (docker) | | | | single: replicas; docker attribute | | | | single: podman; attribute, replicas | | | | single: attribute; replicas (podman) | | | | single: replicas; podman attribute | | | | single: rkt; attribute, replicas | | | | single: attribute; replicas (rkt) | | | | single: replicas; rkt attribute | | | | | | | | A positive integer specifying the number of | | | | container instances to launch | +-------------------+------------------------------------+---------------------------------------------------+ | replicas-per-host | 1 | .. index:: | | | | single: docker; attribute, replicas-per-host | | | | single: attribute; replicas-per-host (docker) | | | | single: replicas-per-host; docker attribute | | | | single: podman; attribute, replicas-per-host | | | | single: attribute; replicas-per-host (podman) | | | | single: replicas-per-host; podman attribute | | | | single: rkt; attribute, replicas-per-host | | | | single: attribute; replicas-per-host (rkt) | | | | single: replicas-per-host; rkt attribute | | | | | | | | A positive integer specifying the number of | | | | container instances allowed to run on a | | | | single node | +-------------------+------------------------------------+---------------------------------------------------+ | promoted-max | 0 | .. index:: | | | | single: docker; attribute, promoted-max | | | | single: attribute; promoted-max (docker) | | | | single: promoted-max; docker attribute | | | | single: podman; attribute, promoted-max | | | | single: attribute; promoted-max (podman) | | | | single: promoted-max; podman attribute | | | | single: rkt; attribute, promoted-max | | | | single: attribute; promoted-max (rkt) | | | | single: promoted-max; rkt attribute | | | | | | | | 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 promoted role | +-------------------+------------------------------------+---------------------------------------------------+ | network | | .. index:: | | | | single: docker; attribute, network | | | | single: attribute; network (docker) | | | | single: network; docker attribute | | | | single: podman; attribute, network | | | | single: attribute; network (podman) | | | | single: network; podman attribute | | | | single: rkt; attribute, network | | | | single: attribute; network (rkt) | | | | single: network; rkt attribute | | | | | | | | If specified, this will be passed to the | | | | ``docker run``, ``podman run``, or | | | | ``rkt run`` command as the network setting | | | | for the container. | +-------------------+------------------------------------+---------------------------------------------------+ | run-command | ``/usr/sbin/pacemaker-remoted`` if | .. index:: | | | bundle contains a **primitive**, | single: docker; attribute, run-command | | | otherwise none | single: attribute; run-command (docker) | | | | single: run-command; docker attribute | | | | single: podman; attribute, run-command | | | | single: attribute; run-command (podman) | | | | single: run-command; podman attribute | | | | single: rkt; attribute, run-command | | | | single: attribute; run-command (rkt) | | | | single: run-command; rkt attribute | | | | | | | | 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). | +-------------------+------------------------------------+---------------------------------------------------+ | options | | .. index:: | | | | single: docker; attribute, options | | | | single: attribute; options (docker) | | | | single: options; docker attribute | | | | single: podman; attribute, options | | | | single: attribute; options (podman) | | | | single: options; podman attribute | | | | single: rkt; attribute, options | | | | single: attribute; options (rkt) | | | | single: options; rkt attribute | | | | | | | | Extra command-line options to pass to the | | | | ``docker run``, ``podman run``, or ``rkt run`` | | | | command | +-------------------+------------------------------------+---------------------------------------------------+ .. 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. .. index:: pair: XML element; network single: bundle; network .. table:: **XML attributes of a network Element** :widths: 2 1 5 +----------------+---------+------------------------------------------------------------+ | Attribute | Default | Description | +================+=========+============================================================+ | add-host | TRUE | .. index:: | | | | single: network; attribute, add-host | | | | single: attribute; add-host (network) | | | | single: add-host; network attribute | | | | | | | | If TRUE, and ``ip-range-start`` is used, Pacemaker will | | | | automatically ensure that ``/etc/hosts`` inside the | | | | containers has entries for each | | | | :ref:`replica name ` | | | | and its assigned IP. | +----------------+---------+------------------------------------------------------------+ | ip-range-start | | .. index:: | | | | single: network; attribute, ip-range-start | | | | single: attribute; ip-range-start (network) | | | | single: ip-range-start; network attribute | | | | | | | | 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. | +----------------+---------+------------------------------------------------------------+ | host-netmask | 32 | .. index:: | | | | single: network; attribute; host-netmask | | | | single: attribute; host-netmask (network) | | | | single: host-netmask; network attribute | | | | | | | | If ``ip-range-start`` is specified, the IP addresses | | | | are created with this CIDR netmask (as a number of bits). | +----------------+---------+------------------------------------------------------------+ | host-interface | | .. index:: | | | | single: network; attribute; host-interface | | | | single: attribute; host-interface (network) | | | | single: host-interface; network attribute | | | | | | | | 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). | +----------------+---------+------------------------------------------------------------+ | control-port | 3121 | .. index:: | | | | single: network; attribute; control-port | | | | single: attribute; control-port (network) | | | | single: control-port; network attribute | | | | | | | | 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. | +----------------+---------+------------------------------------------------------------+ .. _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**. .. index:: pair: XML element; port-mapping Additionally, a ``network`` element may optionally contain one or more ``port-mapping`` elements. .. table:: **Attributes of a port-mapping Element** :widths: 2 1 5 +---------------+-------------------+------------------------------------------------------+ | Attribute | Default | Description | +===============+===================+======================================================+ | id | | .. index:: | | | | single: port-mapping; attribute, id | | | | single: attribute; id (port-mapping) | | | | single: id; port-mapping attribute | | | | | | | | A unique name for the port mapping (required) | +---------------+-------------------+------------------------------------------------------+ | port | | .. index:: | | | | single: port-mapping; attribute, port | | | | single: attribute; port (port-mapping) | | | | single: port; port-mapping attribute | | | | | | | | 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``. | +---------------+-------------------+------------------------------------------------------+ | internal-port | value of ``port`` | .. index:: | | | | single: port-mapping; attribute, internal-port | | | | single: attribute; internal-port (port-mapping) | | | | single: internal-port; port-mapping attribute | | | | | | | | If ``port`` and this are specified, connections | | | | to ``port`` on the host's network will be | | | | forwarded to this port on the container network. | +---------------+-------------------+------------------------------------------------------+ | range | | .. index:: | | | | single: port-mapping; attribute, range | | | | single: attribute; range (port-mapping) | | | | single: range; port-mapping attribute | | | | | | | | 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``. | +---------------+-------------------+------------------------------------------------------+ .. 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``. .. index: pair: XML element; storage pair: XML element; storage-mapping single: bundle; storage .. _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. .. table:: **Attributes of a storage-mapping Element** :widths: 2 1 5 +-----------------+---------+-------------------------------------------------------------+ | Attribute | Default | Description | +=================+=========+=============================================================+ | id | | .. index:: | | | | single: storage-mapping; attribute, id | | | | single: attribute; id (storage-mapping) | | | | single: id; storage-mapping attribute | | | | | | | | A unique name for the storage mapping (required) | +-----------------+---------+-------------------------------------------------------------+ | source-dir | | .. index:: | | | | single: storage-mapping; attribute, source-dir | | | | single: attribute; source-dir (storage-mapping) | | | | single: source-dir; storage-mapping attribute | | | | | | | | 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``. | +-----------------+---------+-------------------------------------------------------------+ | source-dir-root | | .. index:: | | | | single: storage-mapping; attribute, source-dir-root | | | | single: attribute; source-dir-root (storage-mapping) | | | | single: source-dir-root; storage-mapping attribute | | | | | | | | 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 | | | | :ref:`replica name `. | | | | Exactly one of ``source-dir`` and ``source-dir-root`` | | | | must be specified in a ``storage-mapping``. | +-----------------+---------+-------------------------------------------------------------+ | target-dir | | .. index:: | | | | single: storage-mapping; attribute, target-dir | | | | single: attribute; target-dir (storage-mapping) | | | | single: target-dir; storage-mapping attribute | | | | | | | | The path name within the container where the host | | | | storage will be mapped (required) | +-----------------+---------+-------------------------------------------------------------+ | options | | .. index:: | | | | single: storage-mapping; attribute, options | | | | single: attribute; options (storage-mapping) | | | | single: options; storage-mapping attribute | | | | | | | | A comma-separated list of file system mount | | | | options to use when mapping the storage | +-----------------+---------+-------------------------------------------------------------+ .. 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. .. index:: single: bundle; primitive Bundle Primitive ________________ A bundle may optionally contain one :ref:`primitive ` 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 :ref:`clone ` -- a :ref:`promotable clone ` if the bundle has ``promoted-max`` 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 :ref:`storage-mapping ` element to map a file on the host as ``/etc/pacemaker/pcmk-init.env`` in the container *(since 2.0.3)*. 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. .. index:: single: bundle; node attributes .. _s-bundle-attributes: Bundle Node Attributes ______________________ If the bundle has a ``primitive``, the primitive's resource agent may want to set node attributes such as :ref:`promotion scores `. However, with containers, it is not apparent which node should get the attribute. If the container uses shared storage that is the same no matter which node the container is hosted on, then it is appropriate to use the promotion score on the bundle node itself. On the other hand, if the container uses storage exported from the underlying host, then it may be more appropriate to use the promotion score on the underlying host. Since this depends on the particular situation, the ``container-attribute-target`` resource meta-attribute allows the user to specify which approach to use. If it is set to ``host``, then user-defined node attributes will be checked on the underlying host. If it is anything else, the local node (in this case the bundle node) is used as usual. This only applies to user-defined attributes; the cluster will always check the local node for cluster-defined attributes such as ``#uname``. If ``container-attribute-target`` is ``host``, the cluster will pass additional environment variables to the primitive's resource agent that allow it to set node attributes appropriately: ``CRM_meta_container_attribute_target`` (identical to the meta-attribute value) and ``CRM_meta_physical_host`` (the name of the underlying host). .. note:: When called by a resource agent, the ``attrd_updater`` and ``crm_attribute`` commands will automatically check those environment variables and set attributes appropriately. .. index:: single: bundle; meta-attributes 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 :ref:`resource_options` for more information. Bundles support clone meta-attributes including ``notify``, ``ordered``, and ``interleave``. 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``. .. [#] Of course, the service must support running multiple instances. .. [#] Docker is a trademark of Docker, Inc. No endorsement by or association with Docker, Inc. is implied.