add doc for host_maintenance

Change-Id: If9a112d33d7586d828024dbace1863ecc04408d9

doc/source/strategies/host_maintenance.rst

@@ -0,0 +1,92 @@
+===========================
+Host Maintenance Strategy
+===========================
+
+Synopsis
+--------
+
+**display name**: ``Host Maintenance Strategy``
+
+**goal**: ``cluster_maintaining``
+
+    .. watcher-term:: watcher.decision_engine.strategy.strategies.host_maintenance.HostMaintenance
+
+Requirements
+------------
+
+None.
+
+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
+
+Planner
+*******
+
+Default Watcher's planner:
+
+    .. watcher-term:: watcher.decision_engine.planner.weight.WeightPlanner
+
+Configuration
+-------------
+
+Strategy parameters are:
+
+==================== ====== ====================================
+parameter            type   default Value description
+==================== ====== ====================================
+``maintenance_node`` String The name of the compute node which
+                            need maintenance. Required.
+``backup_node``      String The name of the compute node which
+                            will backup the maintenance node.
+                            Optional.
+==================== ====== ====================================
+
+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 ?
+---------------
+
+.. code-block:: shell
+
+    $ openstack optimize audit create \
+      -g cluster_maintaining -s host_maintenance \
+      -p maintenance_node=compute01 \
+      -p backup_node=compute02 \
+      --auto-trigger
+
+External Links
+--------------
+
+None.