Updated nova logic to correct issues with addon devices

The logic within the pre_tasks was too loose. The pre_tasks need
to have a bit more restrictive conditionals. Additionall the
`lxc-device add` command which is being used always exits 0
even when the device add fails. While the task does not have
issues with running we should be making sure that our changes
are being recoreded correctly.

Closes-Bug: 1434945
Change-Id: Icb1707db6bde6c0a26af6bca21a1f88dc3c315a8

playbooks/os-nova-install.yml

@@ -32,8 +32,14 @@
         for i in /dev/nbd*;do
           lxc-device -n {{ container_name }} add $i $i
         done
+      failed_when: false
+      register: device_add
+      changed_when: >
+        'added' in device_add.stdout.lower()
       delegate_to: "{{ physical_host }}"
-      when: is_metal == false or is_metal == "False"
+      when: >
+        inventory_hostname in groups['nova_compute'] and
+        (is_metal == false or is_metal == "False")
       tags:
         - nova-kvm
         - nova-kvm-container-devices
@@ -41,7 +47,9 @@
       shell: |
         lxc-device -n {{ container_name }} add /dev/net/tun /dev/net/tun
       delegate_to: "{{ physical_host }}"
-      when: is_metal == false or is_metal == "False"
+      when: >
+        inventory_hostname in groups['nova_compute'] and
+        (is_metal == false or is_metal == "False")
       tags:
         - nova-kvm
         - nova-kvm-container-devices
@@ -49,7 +57,14 @@
       shell: |
         lxc-device -n {{ container_name }} add /dev/kvm /dev/kvm
       delegate_to: "{{ physical_host }}"
-      when: is_metal == false or is_metal == "False"
+      register: device_add
+      failed_when: false
+      changed_when: >
+        'added' in device_add.stdout.lower()
+      when: >
+        inventory_hostname in groups['nova_compute'] and
+        (is_metal == false or is_metal == "False") and
+        nova_virt_type == 'kvm'
       tags:
         - nova-kvm
         - nova-kvm-container-devices

playbooks/roles/os_nova/tasks/nova_compute.yml

@@ -14,7 +14,9 @@
 # limitations under the License.
 
 - include: nova_compute_kvm.yml
-  when: nova_virt_type == 'kvm' or nova_virt_type == 'qemu'
+  when: >
+    nova_virt_type == 'kvm' or
+    nova_virt_type == 'qemu'
 
 - include: nova_compute_key_create.yml