Add ability to change apt/yum package state

The current method of installing the distribution packages required is
set in the tasks and cannot be changed by a deployer.

Currently the apt task always installs the latest package. This results
in unexpected binary changes when a deployer may simply be trying to
execute a configuration change.

This patch adds the ability for a deployer to change the desired state
so that the results are predictable.

Change-Id: I44271278a353fc222012463431cebc12de0f2f56

defaults/main.yml

@@ -20,6 +20,10 @@ openstack_host_sysstat_enabled: true
 openstack_host_sysstat_interval: 1
 openstack_host_sysstat_statistics_hour: 23
 
+# Set the package install state for distribution packages
+# Options are 'present' and 'latest'
+openstack_hosts_package_state: "latest"
+
 ## Enable/disable /etc/hosts file management
 ## You should make other arrangements for name resolution
 ## of OSA containers and hosts if disabling this

releasenotes/notes/package-state-b41a0e911ad95d1c.yaml

@@ -0,0 +1,13 @@
+---
+features:
+  - The openstack_hosts role now supports the ability to configure whether
+    apt/yum tasks install the latest available package, or just ensure
+    that the package is present. The default action is to ensure that
+    the latest package is present. The action taken may be changed to
+    only ensure that the package is present by setting
+    ``openstack_hosts_package_state`` to ``present``.
+upgrade:
+  - The openstack_hosts role always checks whether the latest package is
+    installed when executed. If a deployer wishes to change the check to
+    only validate the presence of the package, the option
+    ``openstack_hosts_package_state`` should be set to ``present``.

tasks/openstack_host_install_apt.yml

@@ -34,7 +34,7 @@
 - name: Install host packages
   apt:
     pkg: "{{ item }}"
-    state: present
+    state: "{{ openstack_hosts_package_state }}"
   register: install_packages
   until: install_packages|success
   retries: 5