Change defaults for octavia topology and affinity

In most of production deployments it's preferable to have ACTIVE_STANDBY
topology with enable anti-affinity to ensure that loadbalancer
can survive compute node downtime and won't lead to service disruption.

Without these settings it will take quite some time to re-spawn failed
Amphora.

Depends-On: https://review.opendev.org/c/openstack/openstack-ansible/+/866061
Depends-On: https://review.opendev.org/c/openstack/openstack-ansible/+/867052
Change-Id: I4fa437117dce1c973512c09b1bc7d43d411276da

defaults/main.yml

@@ -239,8 +239,7 @@ octavia_required_secrets:
 
 ## Octavia configs
 # Load balancer topology options are SINGLE, ACTIVE_STANDBY
-# ACTIVE_STANDBY is recommended for production settings
-octavia_loadbalancer_topology: SINGLE
+octavia_loadbalancer_topology: ACTIVE_STANDBY
 
 # Image tag for the amphora image in glance
 octavia_glance_image_tag: octavia-amphora-image
@@ -308,8 +307,7 @@ octavia_neutron_oslomsg_rpc_password: "{{ neutron_oslomsg_rpc_password }}"
 # this controls if Octavia should add an anti-affinity hint to make sure
 # two amphora are not placed pn the same host (the most common setup of
 # ant affinity features in Nova).
-# Since AIO only has one compute host this is set to false
-octavia_enable_anti_affinity: False
+octavia_enable_anti_affinity: True
 
 # Some installations put hardware more suited for load balancing in special
 # availability zones. This allows to target a specific availability zone

releasenotes/notes/octavia_default_topology-91f574bbaed85249.yaml

@@ -0,0 +1,8 @@
+---
+upgrade:
+  - |
+    Default values for variables ``octavia_loadbalancer_topology`` and
+    ``octavia_enable_anti_affinity`` has been switched to ``ACTIVE_STANDBY``
+    and ``True`` accordingly to reflect most reasonable production setup.
+    You can define these variables to their previous defaults if you want
+    to preserve behaviour.