MNAIO: Add access to libvirt v4 via UCA Queens

When using an Ubuntu Xenial host, this patch adds the Ubuntu
Cloud Archive Queens repository so that the MNAIO tooling
makes use of libvirt v4. This provides access to a better
snapshot and snapshot-revert implementation, among other
features.

To improve the chances of success during builds, retries
are added to the package install tasks. Also, given that
we're using Ansible > 2.1.x, we forgo the with_items loop
for the package installs and just give the package module
the list so that it installs them all at once.

Change-Id: I0373e29fb996de1538465277760a0181289cbb44

multi-node-aio/playbooks/setup-host.yml

@@ -28,13 +28,55 @@
       tags:
         - always
 
-    - name: Install host distro packages
+    - name: Install pre-requisite host distro packages
       package:
-        pkg: "{{ item }}"
+        name: "{{ mnaio_host_required_distro_packages }}"
         state: "latest"
         update_cache: yes
         cache_valid_time: 600
-      with_items: "{{ mnaio_host_distro_packages }}"
+      register: _install_required_host_packages
+      until: _install_required_host_packages | success
+      retries: 3
+      delay: 15
+      when:
+        - "mnaio_host_required_distro_packages | length > 0"
+
+    - name: Add/Remove/Update apt repositories
+      apt_repository:
+        repo: "{{ repo.repo }}"
+        state: "{{ repo.state | default('present') }}"
+        filename: "{{ repo.filename | default(omit) }}"
+        update_cache: no
+      with_items: "{{ mnaio_host_package_repos }}"
+      loop_control:
+        loop_var: repo
+      register: _add_apt_repo
+      when:
+        - "ansible_os_family == 'Debian'"
+        - "mnaio_host_package_repos | length > 0"
+        - "(repo.condition | default(True)) | bool"
+
+    - name: Update apt cache
+      apt:
+        update_cache: yes
+      register: _update_apt_cache
+      until: _update_apt_cache | success
+      retries: 3
+      delay: 15
+      when:
+        - "ansible_os_family == 'Debian'"
+        - "_add_apt_repo | changed"
+
+    - name: Install host distro packages
+      package:
+        name: "{{ mnaio_host_distro_packages }}"
+        state: "latest"
+        update_cache: yes
+        cache_valid_time: 600
+      register: _install_host_packages
+      until: _install_host_packages | success
+      retries: 3
+      delay: 15
 
   tasks:
     - name: Ensure root has a .ssh directory

multi-node-aio/playbooks/vars/ubuntu.yml

@@ -13,6 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+mnaio_host_required_distro_packages:
+  - ubuntu-cloud-keyring
+
+mnaio_host_package_repos:
+  - repo: "deb http://ubuntu-cloud.archive.canonical.com/ubuntu {{ ansible_lsb.codename }}-updates/queens main"
+    state: present
+    filename: "uca"
+    condition: "{{ ansible_lsb.codename == 'xenial' }}"
+
 mnaio_host_distro_packages:
   - bridge-utils
   - ifenslave