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:
Resources
~~~~~~~~~
+[thumbnail="gui-ha-manager-resources-view.png"]
+
The resource configuration file `/etc/pve/ha/resources.cfg` stores
the list of resources managed by `ha-manager`. A resource configuration
inside that list look like this:
# Note: use default settings for everything
----
+[thumbnail="gui-ha-manager-add-resource.png"]
+
Above config was generated using the `ha-manager` command line tool:
----
Groups
~~~~~~
+[thumbnail="gui-ha-manager-groups-view.png"]
+
The HA group configuration file `/etc/pve/ha/groups.cfg` is used to
define groups of cluster nodes. A resource can be restricted to run
only on the members of such group. A group configuration look like
include::ha-groups-opts.adoc[]
+[thumbnail="gui-ha-manager-add-group.png"]
+
A commom requirement is that a resource should run on a specific
node. Usually the resource is able to run on other nodes, so you can define
an unrestricted group with a single member:
recovered services move straight back to the fenced node.
-Node Power Status
------------------
-
-If a node needs maintenance you should migrate and or relocate all
-services which are required to run always on another node first.
-After that you can stop the LRM and CRM services. But note that the
-watchdog triggers if you stop it with active services.
-
-
-[[ha_manager_package_updates]]
-Package Updates
----------------
-
-When updating the ha-manager you should do one node after the other, never
-all at once for various reasons. First, while we test our software
-thoughtfully, a bug affecting your specific setup cannot totally be ruled out.
-Upgrading one node after the other and checking the functionality of each node
-after finishing the update helps to recover from an eventual problems, while
-updating all could render you in a broken cluster state and is generally not
-good practice.
-
-Also, the {pve} HA stack uses a request acknowledge protocol to perform
-actions between the cluster and the local resource manager. For restarting,
-the LRM makes a request to the CRM to freeze all its services. This prevents
-that they get touched by the Cluster during the short time the LRM is restarting.
-After that the LRM may safely close the watchdog during a restart.
-Such a restart happens on a update and as already stated a active master
-CRM is needed to acknowledge the requests from the LRM, if this is not the case
-the update process can be too long which, in the worst case, may result in
-a watchdog reset.
-
-
[[ha_manager_fencing]]
Fencing
-------
* *after* you fixed all errors you may enable the service again
+Node Maintenance
+----------------
+
+It is sometimes possible to shutdown or reboot a node to do
+maintenance tasks. Either to replace hardware, or simply to install a
+new kernel image.
+
+
+Shutdown
+~~~~~~~~
+
+A shutdown ('poweroff') is usually done if the node is planned to stay
+down for some time. The LRM stops all managed services in that
+case. This means that other nodes will take over those service
+afterwards.
+
+NOTE: Recent hardware has large amounts of RAM. So we stop all
+resources, then restart them to avoid online migration of all that
+RAM. If you want to use online migration, you need to invoke that
+manually before you shutdown the node.
+
+
+Reboot
+~~~~~~
+
+Node reboots are initiated with the 'reboot' command. This is usually
+done after installing a new kernel. Please note that this is different
+from ``shutdown'', because the node immediately starts again.
+
+The LRM tells the CRM that it wants to restart, and waits until the
+CRM puts all resources into the `freeze` state. This prevents that
+those resources are moved to other nodes. Instead, the CRM start the
+resources after the reboot on the same node.
+
+
+Manual Resource Movement
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Last but not least, you can also move resources manually to other
+nodes before you shutdown or restart a node. The advantage is that you
+have full control, and you can decide if you want to use online
+migration or not.
+
+NOTE: Please do not 'kill' services like `pve-ha-crm`, `pve-ha-lrm` or
+`watchdog-mux`. They manage and use the watchdog, so this can result
+in a node reboot.
+
+
+[[ha_manager_package_updates]]
+Package Updates
+---------------
+
+When updating the ha-manager you should do one node after the other, never
+all at once for various reasons. First, while we test our software
+thoughtfully, a bug affecting your specific setup cannot totally be ruled out.
+Upgrading one node after the other and checking the functionality of each node
+after finishing the update helps to recover from an eventual problems, while
+updating all could render you in a broken cluster state and is generally not
+good practice.
+
+Also, the {pve} HA stack uses a request acknowledge protocol to perform
+actions between the cluster and the local resource manager. For restarting,
+the LRM makes a request to the CRM to freeze all its services. This prevents
+that they get touched by the Cluster during the short time the LRM is restarting.
+After that the LRM may safely close the watchdog during a restart.
+Such a restart happens on a update and as already stated a active master
+CRM is needed to acknowledge the requests from the LRM, if this is not the case
+the update process can be too long which, in the worst case, may result in
+a watchdog reset.
+
+
[[ha_manager_service_operations]]
Service Operations
------------------
projects / pve-docs.git / blobdiff