commit a9f5d9767242d617751a270db2f66cf98038c789
Author: Dmitriy Rabotyagov <noonedeadpunk@ya.ru>
Date:   Tue Oct 6 18:14:34 2020 +0300

    Define condition for the first play host one time
    
    We use the same condition, which defines against what host some "service"
    tasks should run against, several times. It's hard to keep it the same
    across the role and ansible spending additional resources to evaluate
    it each time, so it's simpler and better for the maintenance to set
    a boolean variable which will say for all tasks, that we want to run
    only against signle host, if they should run or not now.
    
    Change-Id: I78d44704a0224b2c73832a607e84ea8d9499f8c2

diff --git a/tasks/main.yml b/tasks/main.yml
index 75b287e..40d11dd 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -71,8 +71,7 @@
 
 - import_tasks: db_setup.yml
   when:
-    - "nova_services['nova-conductor']['group'] in group_names"
-    - "inventory_hostname == ((groups[nova_services['nova-conductor']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - _nova_is_first_play_host
   vars:
     _oslodb_setup_host: "{{ nova_db_setup_host }}"
     _oslodb_ansible_python_interpreter: "{{ nova_db_setup_python_interpreter }}"
@@ -97,8 +96,7 @@
 
 - import_tasks: mq_setup.yml
   when:
-    - "nova_services['nova-conductor']['group'] in group_names"
-    - "inventory_hostname == ((groups[nova_services['nova-conductor']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - _nova_is_first_play_host
   vars:
     _oslomsg_rpc_setup_host: "{{ nova_oslomsg_rpc_setup_host }}"
     _oslomsg_rpc_userid: "{{ nova_oslomsg_rpc_userid }}"
@@ -172,15 +170,13 @@
         type: "{{ nova_service_type }}"
         description: "{{ nova_service_description }}"
   when:
-    - "nova_services['nova-conductor']['group'] in group_names"
-    - "inventory_hostname == ((groups['nova_conductor'] | intersect(ansible_play_hosts)) | list)[0]"
+    - _nova_is_first_play_host
   tags:
     - nova-config
 
 - import_tasks: nova_db_setup.yml
   when:
-    - "nova_services['nova-conductor']['group'] in group_names"
-    - "inventory_hostname == ((groups['nova_conductor'] | intersect(ansible_play_hosts)) | list)[0]"
+    - _nova_is_first_play_host
   tags:
     - nova-config
 
diff --git a/vars/main.yml b/vars/main.yml
index fb6d4c6..ee67763 100644
--- a/vars/main.yml
+++ b/vars/main.yml
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+_nova_is_first_play_host: "{{ (nova_services['nova-conductor']['group'] in group_names and inventory_hostname == (groups[nova_services['nova-conductor']['group']] | intersect(ansible_play_hosts)) | first) | bool }}"
+
 nova_venv_packages: |-
   {%- set pkg_list = nova_pip_packages | union(nova_user_pip_packages) %}
   {%- if nova_oslomsg_amqp1_enabled | bool %}