containers. One basic idea here is that we can bundle related software
into such VM or container, so there is no need to compose one big
service from other services, like it was done with `rgmanager`. In
-general, a HA enabled resource should not depend on other resources.
+general, a HA managed resource should not depend on other resources.
+
+
+Management Tasks
+----------------
+
+This section provides a short overview of common management tasks. The
+first step is to enable HA for a resource. This is done by adding the
+resource to the HA resource configuration. You can do this using the
+GUI, or simply use the command line tool, for example:
+
+----
+# ha-manager add vm:100
+----
+
+The HA stack now tries to start the resources and keeps it
+running. Please note that you can configure the ``requested''
+resources state. For example you may want that the HA stack stops the
+resource:
+
+----
+# ha-manager set vm:100 --state stopped
+----
+
+and start it again later:
+
+----
+# ha-manager set vm:100 --state started
+----
+
+You can also use the normal VM and container management commands. They
+automatically forward the commands to the HA stack, so
+
+----
+# qm start 100
+----
+
+simply sets the requested state to `started`. Same applied to `qm
+stop`, which sets the requested state to `stopped`.
+
+NOTE: The HA stack works fully asynchronous and needs to communicate
+with other cluster members. So it takes some seconds unless you see
+the result of such actions.
+
+To view the current HA resource configuration use:
+
+----
+# ha-manager config
+vm:100
+ state stopped
+----
+
+And you can view the actual HA manager and resource state with:
+
+----
+# ha-manager status
+quorum OK
+master node1 (active, Wed Nov 23 11:07:23 2016)
+lrm elsa (active, Wed Nov 23 11:07:19 2016)
+service vm:100 (node1, started)
+----
+
+You can also initiate resource migration to other nodes:
+
+----
+# ha-manager migrate vm:100 node2
+----
+
+This uses online migration and tries to keep the VM running. Online
+migration needs to transfer all used memory over the network, so it is
+sometimes faster to stop VM, then restart it on the new node. This can be
+done using the `relocate` command:
+
+----
+# ha-manager relocate vm:100 node2
+----
+
+Finally, you can remove the resource from the HA configuration using
+the following command:
+
+----
+# ha-manager remove vm:100
+----
+
+NOTE: This does not start or stop the resource.
+
+But all HA related task can be done on the GUI, so there is no need to
+use the command line at all.
How It Works
Service States
~~~~~~~~~~~~~~
-[thumbnail="gui-ha-manager-status.png"]
-
The CRM use a service state enumeration to record the current service
state. We display this state on the GUI and you can query it using
the `ha-manager` command line tool:
Service should be stopped. The CRM waits for confirmation from the
LRM.
+stopping::
+
+Pending stop request. But the CRM did not get the request so far.
+
started::
Service is active an LRM should start it ASAP if not already running.
restarts it
(see xref:ha_manager_start_failure_policy[Start Failure Policy]).
+starting::
+
+Pending start request. But the CRM has not got any confirmation from the
+LRM that the service is running.
+
fence::
Wait for node fencing (service node is not inside quorate cluster
Service is disabled because of LRM errors. Needs manual intervention
(see xref:ha_manager_error_recovery[Error Recovery]).
+queued::
+
+Service is newly added, and the CRM has not seen it so far.
+
+disabled::
+
+Service is stopped and marked as `disabled`
+
Local Resource Manager
~~~~~~~~~~~~~~~~~~~~~~
The CRM lost its lock, this means a failure happened and quorum was lost.
It main task is to manage the services which are configured to be highly
-available and try to always enforce them to the wanted state, e.g.: a
-enabled service will be started if its not running, if it crashes it will
-be started again. Thus it dictates the LRM the actions it needs to execute.
+available and try to always enforce the requested state. For example, a
+service with the requested state 'started' will be started if its not
+already running. If it crashes it will be automatically started again.
+Thus the CRM dictates the actions which the LRM needs to execute.
When an node leaves the cluster quorum, its state changes to unknown.
If the current CRM then can secure the failed nodes lock, the services
the same HA configuration.
+[[ha_manager_resource_config]]
Resources
~~~~~~~~~
-[thumbnail="gui-ha-manager-resources-view.png"]
+[thumbnail="gui-ha-manager-status.png"]
+
The resource configuration file `/etc/pve/ha/resources.cfg` stores
the list of resources managed by `ha-manager`. A resource configuration
NOTE: The relocate count state will only reset to zero when the
service had at least one successful start. That means if a service is
-re-enabled without fixing the error only the restart policy gets
+re-started without fixing the error only the restart policy gets
repeated.
If after all tries the service state could not be recovered it gets
placed in an error state. In this state the service won't get touched
-by the HA stack anymore. To recover from this state you should follow
-these steps:
+by the HA stack anymore. The only way out is disabling a service:
-* bring the resource back into a safe and consistent state (e.g.,
-killing its process)
+----
+# ha-manager set vm:100 --state disabled
+----
+
+This can also be done in the web interface.
+
+To recover from the error state you should do the following:
+
+* bring the resource back into a safe and consistent state (e.g.:
+kill its process if the service could not be stopped)
-* disable the ha resource to place it in an stopped state
+* disable the resource to remove the error flag
* fix the error which led to this failures
-* *after* you fixed all errors you may enable the service again
+* *after* you fixed all errors you may request that the service starts again
[[ha_manager_package_updates]]
in a node reboot.
-[[ha_manager_service_operations]]
-Service Operations
-------------------
-
-This are how the basic user-initiated service operations (via
-`ha-manager`) work.
-
-enable::
-
-The service will be started by the LRM if not already running.
-
-disable::
-
-The service will be stopped by the LRM if running.
-
-migrate/relocate::
-
-The service will be relocated (live) to another node.
-
-remove::
-
-The service will be removed from the HA managed resource list. Its
-current state will not be touched.
-
-start/stop::
-
-`start` and `stop` commands can be issued to the resource specific tools
-(like `qm` or `pct`), they will forward the request to the
-`ha-manager` which then will execute the action and set the resulting
-service state (enabled, disabled).
-
-
ifdef::manvolnum[]
include::pve-copyright.adoc[]
endif::manvolnum[]
projects / pve-docs.git / blobdiff