Disable heartbeat_in_pthread by default

The default value for heartbeat_in_pthread has been reverted in
oslo.messaging to False [1] and backported back to Yoga.

At the moment this setting brings intermittent issues during live
migrations of instances and some other operations. So makes sense
to align it with default value.

[1] https://review.opendev.org/c/openstack/oslo.messaging/+/852251

Change-Id: I5601726095ff19620de2d87220efad191cf7cb6d
(cherry picked from commit d40f5a47259a8f5b22d409c470e954b6afe8a23f)

defaults/main.yml

@@ -130,7 +130,7 @@ nova_cell1_name: "cell1"
 ## Oslo Messaging
 
 # RabbitMQ
-nova_oslomsg_heartbeat_in_pthread: "{{ oslomsg_heartbeat_in_pthread | default(_nova_oslomsg_heartbeat_in_pthread) }}"
+nova_oslomsg_heartbeat_in_pthread: "{{ oslomsg_heartbeat_in_pthread | default(False) }}"
 
 # RPC
 nova_oslomsg_rpc_host_group: "{{ oslomsg_rpc_host_group | default('rabbitmq_all') }}"

releasenotes/notes/heartbeat_in_pthread_to_false-4bde8fca9a332805.yaml

@@ -0,0 +1,8 @@
+---
+other:
+  - |
+    In order to align with oslo.messaging `reverted default <https://review.opendev.org/c/openstack/oslo.messaging/+/852251>`_
+    of ``heartbeat_in_pthread`` value we remove own logic of
+    handling the value based on host groups.
+    You still can use ``oslomsg_heartbeat_in_pthread`` or specific role
+    variables to alter the behaviour.

vars/main.yml

@@ -151,8 +151,6 @@ _qemu_default_conf_dict: |-
 
 _nova_qemu_conf: "{{ _qemu_default_conf_dict | combine(qemu_conf_dict) }}"
 
-_nova_oslomsg_heartbeat_in_pthread: "{{ (nova_services['nova-compute']['group'] in group_names) | ternary(False, True) }}"
-
 _nova_cache_backend_map:
   dogpile:
     - oslo_cache.memcache_pool