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: Ic7277f4d3c6697a5be2fa86e07f8b19f0c5db069

handlers/main.yml

@@ -56,8 +56,7 @@
   delegate_to: "{{ groups[neutron_services['neutron-server']['group']][0] }}"
   when:
     - "ansible_local['openstack_ansible']['neutron']['need_db_contract'] | bool"
-    - "neutron_services['neutron-server']['group'] in group_names"
-    - "inventory_hostname == ((groups[neutron_services['neutron-server']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - "_neutron_is_first_play_host"
   listen:
     - "Restart neutron services"
     - "venv changed"

tasks/main.yml

@@ -34,8 +34,7 @@
 
 - import_tasks: db_setup.yml
   when:
-    - "neutron_services['neutron-server']['group'] in group_names"
-    - "inventory_hostname == ((groups[neutron_services['neutron-server']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - "_neutron_is_first_play_host"
   vars:
     _oslodb_setup_host: "{{ neutron_db_setup_host }}"
     _oslodb_ansible_python_interpreter: "{{ neutron_db_setup_python_interpreter }}"
@@ -52,8 +51,7 @@
 
 - import_tasks: mq_setup.yml
   when:
-    - "neutron_services['neutron-server']['group'] in group_names"
-    - "inventory_hostname == ((groups[neutron_services['neutron-server']['group']]| intersect(ansible_play_hosts)) | list)[0]"
+    - "_neutron_is_first_play_host"
   vars:
     _oslomsg_rpc_setup_host: "{{ neutron_oslomsg_rpc_setup_host }}"
     _oslomsg_rpc_userid: "{{ neutron_oslomsg_rpc_userid }}"
@@ -208,8 +206,7 @@
         type: "{{ neutron_service_type }}"
         description: "{{ neutron_service_description }}"
   when:
-    - "neutron_services['neutron-server']['group'] in group_names"
-    - "inventory_hostname == ((groups[neutron_services['neutron-server']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - "_neutron_is_first_play_host"
   tags:
     - neutron-config
 

tasks/neutron_db_setup.yml

@@ -19,7 +19,7 @@
   become_user: "{{ neutron_system_user_name }}"
   when:
     - "ansible_local['openstack_ansible']['neutron']['need_db_expand'] | bool"
-    - "inventory_hostname == ((groups[neutron_services['neutron-server']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - "_neutron_is_first_play_host"
 
 - name: Disable the db expand fact
   ini_file:
@@ -35,7 +35,7 @@
   become: yes
   become_user: "{{ neutron_system_user_name }}"
   when:
-    - "inventory_hostname == ((groups[neutron_services['neutron-server']['group']] | intersect(ansible_play_hosts)) | list)[0]"
+    - "_neutron_is_first_play_host"
   changed_when: false
   register: _offline_migrations_check
   failed_when:

tasks/neutron_post_install.yml

@@ -100,7 +100,7 @@
     flat: yes
   changed_when: false
   with_items: "{{ neutron_core_files }}"
-  run_once: true
+  when: _neutron_is_first_play_host
 
 - name: Copy common neutron config
   config_template:

vars/main.yml

@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+_neutron_is_first_play_host: "{{ (neutron_services['neutron-server']['group'] in group_names and inventory_hostname == (groups[neutron_services['neutron-server']['group']] | intersect(ansible_play_hosts)) | first) | bool }}"
+
 ###
 ### Open vSwitch
 ###