Add etcd environment definition

Instead of requiring the user to define an env.d override to deploy
etcd when Calico is used, we can provide a default etcd environment
definition that will only deploy etcd containers if 'etcd_hosts'
are defined in the openstack_user_config.

There is no upgrade impact because users who already use calico
will have an out of tree environment defintion in
/etc/openstack_deploy/env.d which overrides the in-tree version.

Change-Id: Id395ae972ea821b36f3b4ae09f4c72280256e676

etc/openstack_deploy/conf.d/etcd.conf.example

@@ -0,0 +1,9 @@
+# The infra nodes that will be running the etcd containers (only used if the
+# calico plugin is enabled for Neutron)
+etcd_hosts:
+  infra1:
+    ip: 172.20.236.111
+  infra2:
+    ip: 172.20.236.112
+  infra3:
+    ip: 172.20.236.113

playbooks/inventory/env.d/etcd.yml

@@ -0,0 +1,34 @@
+---
+# Copyright 2017, Logan Vig <logan2211@gmail.com>
+#
+# 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.
+
+component_skel:
+  etcd:
+    belongs_to:
+      - etcd_all
+
+container_skel:
+  etcd_container:
+    belongs_to:
+      - etcd_containers
+    contains:
+      - etcd
+
+physical_skel:
+  etcd_containers:
+    belongs_to:
+      - all_containers
+  etcd_hosts:
+    belongs_to:
+      - hosts

tests/test_inventory.py

@@ -192,6 +192,11 @@ class TestAnsibleInventoryFormatConstraints(unittest.TestCase):
         'designate_worker',
         'designate_producer',
         'designate_sink',
+        'etcd',
+        'etcd_all',
+        'etcd_container',
+        'etcd_containers',
+        'etcd_hosts',
         'galera',
         'galera_all',
         'galera_container',