Fixed hosts inclusion when requiring the lxc_hosts role

The lxc host role was being pinned to specific hosts under the assumption
that only those host types would ever run lxc containers. This becomes an
issue when the host groups have been used outside of our "nornal" pattern
used in the gate. Simple changes to the "openstack_user_config.yml" file
can cause containers to be built in hosts not covered by our current pins.

Common example where the old group would not work:
  http://paste.openstack.org/show/565045/

To correct this issue a new play has been added under "common-plays" which
generates a group of known hosts which we know will require the "lxc_host"
role.

Change-Id: I99eb876f1d089a73ae162f5629422dc492a99d09
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

playbooks/common-plays/generate-lxc-container-hosts.yml

@@ -0,0 +1,34 @@
+---
+# Copyright 2016, Rackspace US, Inc.
+#
+# 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.
+
+- name: Generate container host list
+  hosts: localhost
+  connection: local
+  gather_facts: false
+  tasks:
+    - set_fact:
+        _container_hosts: >
+          {%- for item in groups['all_containers'] -%}
+          {%-   if hostvars[item]['physical_host'] | default(false) != item -%}
+          {{ hostvars[item]['physical_host'] }}{% if not loop.last %},{% endif %}
+          {%-   endif -%}
+          {%- endfor -%}
+    - set_fact:
+        _known_container_hosts: "{{ _container_hosts | replace('\n', '') }}"
+    - name: Create dynamic lxc_host group
+      add_host:
+        hostname: "{{ item }}"
+        groups: "known_container_hosts"
+      with_items: "{{ _known_container_hosts.split(',') | unique }}"

playbooks/lxc-hosts-setup.yml

@@ -13,19 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+- include: common-plays/generate-lxc-container-hosts.yml
+
 - name: Basic lxc host setup
-  hosts: >
+  hosts: known_container_hosts
-    {{ lxc_host_group |
-       default('
-         shared-infra_hosts
-         :os-infra_hosts
-         :repo-infra_hosts
-         :identity_hosts
-         :storage-infra_hosts
-         :log_hosts
-         :network_hosts
-       ')
-    }}
   gather_facts: "{{ gather_facts | default(True) }}"
   max_fail_percentage: 20
   user: root