Automate collectd_container var

This patch automates collectd_container var to set to true  if running on OpenStack version
Stein or later and set to false for below OpenStack version which was manually done earlier.

Change-Id: Idd61f060a088caa1eae9d2a80e3c7ceb5debc424

ansible/install/collectd.yml

@@ -1,9 +1,11 @@
 ---
+- name: set fact collectd_container
+  import_playbook: pre-collectd.yml
+
 - name: Run containerized collectd (Stein and greater recommended)
   import_playbook: collectd-container.yml
-  when: collectd_container
+  when: hostvars['undercloud']['collectd_container']
 
 - name: Run collectd installed through RPMs
   import_playbook: collectd-baremetal.yml
-  when: not collectd_container
-
+  when: not hostvars['undercloud']['collectd_container']

ansible/install/group_vars/all.yml

@@ -144,8 +144,6 @@ repos: {}
 # Collectd Configuration
 ########################################
 # Install release specific templates
-# Set collectd_container true for OSP >= 15
-collectd_container: true
 # Install collectd from EPEL
 collectd_from_epel: true
 # Interval in seconds

ansible/install/pre-collectd.yml

@@ -0,0 +1,8 @@
+---
+- hosts: undercloud
+  roles:
+    - { role: osp_version }
+  tasks:
+    - name: set fact collectd_container
+      set_fact:
+        collectd_container: "{{ (rhosp_major|int > 14)| ternary(true, false) }}"

doc/source/installation.rst

@@ -82,8 +82,7 @@ has been installed. To skip directly to this task execute:
 (Optional) Install Collectd
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Set ``collectd_container`` to true in ``ansible/install/group_vars/all.yml`` if running on OpenStack version Stein or later. The containerized collectd work
-can also work with Queens release but it is not recommended.
+``collectd_container`` is set to true if running on OpenStack version Stein or later. The containerized collectd can also work with Queens release but it is not recommended.
 
 ::