[DOC] Add node aggregate manage docs

Change-Id: I7eb1331c5e6ae058cd88177b2875789fa049daa2

doc/source/admin/aggregates.rst

@@ -0,0 +1,59 @@
+..
+      Copyright 2012 OpenStack Foundation
+      Copyright 2012 Citrix Systems, Inc.
+      Copyright 2012, The Cloudscaling Group, Inc.
+      All Rights Reserved.
+
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+Node Aggregates
+===============
+
+Node aggregates, like nova's host aggregates for VMs, can be regarded as a mechanism
+to further partition an availability zone; while availability zones are visible to
+users, node aggregates are only visible to administrators. Allow administrators to
+assign key-value pairs to groups of bare metal nodes. Each node can have multiple
+aggregates, each aggregate can have multiple key-value pairs, and the same key-value
+pair can be assigned to multiple aggregates. This information can be used in the
+scheduler to enable advanced scheduling by setting key-value pairs to flavor resource
+aggregates field.
+
+Admin users can use the :command:`openstack baremetalcompute aggregate` command to
+create, delete and manage aggregates. To see information for this command, run:
+
+.. code-block:: console
+
+    $ openstack baremetalcompute aggregate [TAB]
+    add        create     delete     list       list_node  remove     set        show       unset
+
+Availability Zones (AZs)
+------------------------
+
+Like Nova, the availability zone is actually a specific metadata attached to
+an aggregate. Adding that specific metadata to an aggregate makes the aggregate
+visible from an end-user perspective and consequently allows to schedule upon a
+specific set of nodes (the ones belonging to the aggregate).
+
+.. note:: One node can be in multiple aggregates, but it can only be in one
+  availability zone
+
+
+Affinity Zones
+--------------
+
+The affinity zone is also a specific metadata attached to an aggregate, which
+makes server group affinity and anti-affinity happen. You may define it as
+failure domains(e.g., by power circuit, rack, room, etc).
+
+.. note:: One node can be in multiple aggregates, but it can only be in one
+  affinity zone

doc/source/index.rst

@@ -69,6 +69,7 @@ Administrator Guide
   :maxdepth: 1
 
   admin/flavors
+  admin/aggregates
   admin/gmr