Enables override of Octavia notification topics

Octavia was missing an override for enabling notification topics,
this aligns the overrides with how all the other project roles
handle the topic.

Closes-Bug: #2087997
Change-Id: Icbe25c0f4107128db899c0111af3acf3c513008f
Signed-off-by: Antony Messerli <[email protected]>
(cherry picked from commit 41b4166)

Author: antonym

ansible/roles/octavia/defaults/main.yml

@@ -270,6 +270,15 @@ octavia_ks_users:
     password: "{{ octavia_keystone_password }}"
     role: "admin"
 
+####################
+# Notification
+####################
+octavia_notification_topics:
+  - name: notifications
+    enabled: "{{ enable_ceilometer | bool }}"
+
+octavia_enabled_notification_topics: "{{ octavia_notification_topics | selectattr('enabled', 'equalto', true) | list }}"
+
 ####################
 # Kolla
 ####################

ansible/roles/octavia/templates/octavia.conf.j2

@@ -122,6 +122,12 @@ rpc_thread_pool_size = 2
 
 [oslo_messaging_notifications]
 transport_url = {{ notify_transport_url }}
+{% if octavia_enabled_notification_topics %}
+driver = messagingv2
+topics = {{ octavia_enabled_notification_topics | map(attribute='name') | join(',') }}
+{% else %}
+driver = noop
+{% endif %}
 
 [oslo_messaging_rabbit]
 use_queue_manager = true

releasenotes/notes/octavia-notifications-98a91ab02d9cbee6.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Adds a missing override for ``octavia_notification_topics`` so that
+    operators can add their own notification topics for Octavia. By
+    default it will send notifications to ceilometer when ceilometer
+    is enabled.