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|
===========================
Host Maintenance Strategy
===========================
Synopsis
--------
**display name**: ``Host Maintenance Strategy``
**goal**: ``cluster_maintaining``
.. watcher-term:: watcher.decision_engine.strategy.strategies.host_maintenance.HostMaintenance
Metrics
*******
None
Cluster data model
******************
Default Watcher's Compute cluster data model:
.. watcher-term:: watcher.decision_engine.model.collector.nova.NovaClusterDataModelCollector
Actions
*******
Default Watcher's actions:
.. list-table::
:widths: 30 30
:header-rows: 1
* - action
- description
* - ``migration``
- .. watcher-term:: watcher.applier.actions.migration.Migrate
* - ``change_nova_service_state``
- .. watcher-term:: watcher.applier.actions.change_nova_service_state.ChangeNovaServiceState
Planner
*******
Default Watcher's planner:
.. watcher-term:: watcher.decision_engine.planner.weight.WeightPlanner
Configuration
-------------
Strategy parameters are:
========================== ======== ========================== ==========
parameter type description required
========================== ======== ========================== ==========
``maintenance_node`` String The name of the Required
compute node
which needs maintenance.
``backup_node`` String The name of the compute Optional
node which will backup
the maintenance node.
``disable_live_migration`` Boolean False: Active instances Optional
will be live migrated.
True: Active instances
will be cold migrated
if cold migration is
not disabled. Otherwise,
they will be stopped.
False by default.
``disable_cold_migration`` Boolean False: Inactive instances Optional
will be cold migrated.
True: Inactive instances
will not be cold migrated.
False by default.
========================== ======== ========================== ==========
Efficacy Indicator
------------------
None
Algorithm
---------
For more information on the Host Maintenance Strategy please refer
to: https://specs.openstack.org/openstack/watcher-specs/specs/queens/approved/cluster-maintenance-strategy.html
How to use it ?
---------------
Run an audit using Host Maintenance strategy.
Executing the actions will move the servers from compute01 host
to a host determined by the Nova scheduler service.
.. code-block:: shell
$ openstack optimize audit create \
-g cluster_maintaining -s host_maintenance \
-p maintenance_node=compute01
Run an audit using Host Maintenance strategy with a backup node specified.
Executing the actions will move the servers from compute01 host
to compute02 host.
.. code-block:: shell
$ openstack optimize audit create \
-g cluster_maintaining -s host_maintenance \
-p maintenance_node=compute01 \
-p backup_node=compute02
Run an audit using Host Maintenance strategy with migration disabled.
This will only stop active instances on compute01, useful for maintenance
scenarios where operators do not want to migrate workloads to other hosts.
.. code-block:: shell
$ openstack optimize audit create \
-g cluster_maintaining -s host_maintenance \
-p maintenance_node=compute01 \
-p disable_live_migration=True \
-p disable_cold_migration=True
Note that after executing this strategy, the *maintenance_node* will be
marked as disabled, with the reason set to ``watcher_maintaining``.
To enable the node again:
.. code-block:: shell
$ openstack compute service set --enable compute01
External Links
--------------
None.
|
