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.

Depends-On: https://review.opendev.org/758953
Change-Id: Iab3194322e133282fcb71830f2b94e1279106ebd

tasks/ironic_db_setup.yml

@@ -25,5 +25,4 @@
   become: yes
   changed_when: false
   when:
-    - ironic_services['ironic-inspector']['group'] in group_names
-    - inventory_hostname == groups[ironic_services['ironic-inspector']['group']][0]
+    - _ironic_inspector_is_first_play_host

tasks/ironic_post_install.yml

@@ -25,7 +25,7 @@
     OS_ENDPOINT_TYPE: internalURL
   when:
     - not ironic_enable_web_server_for_images | bool
-    - inventory_hostname == groups['ironic_all'][0]
+    - _ironic_api_is_first_play_host
     - not ironic_standalone | bool
   tags:
     - always

tasks/main.yml

@@ -26,8 +26,7 @@
 
 - import_tasks: db_setup.yml
   when:
-    - "ironic_services['ironic-api']['group'] in group_names"
-    - "inventory_hostname == ((groups[ironic_services['ironic-api']['group']]| intersect(ansible_play_hosts)) | list)[0]"
+    - _ironic_api_is_first_play_host
   vars:
     _oslodb_setup_host: "{{ ironic_db_setup_host }}"
     _oslodb_ansible_python_interpreter: "{{ ironic_db_setup_python_interpreter }}"
@@ -44,8 +43,7 @@
 
 - import_tasks: db_setup.yml
   when:
-    - "ironic_services['ironic-inspector']['group'] in group_names"
-    - "inventory_hostname == ((groups[ironic_services['ironic-inspector']['group']]| intersect(ansible_play_hosts)) | list)[0]"
+    - _ironic_inspector_is_first_play_host
   vars:
     _oslodb_setup_host: "{{ ironic_inspector_db_setup_host }}"
     _oslodb_ansible_python_interpreter: "{{ ironic_inspector_db_setup_python_interpreter }}"
@@ -62,8 +60,7 @@
 
 - import_tasks: mq_setup.yml
   when:
-    - "ironic_services['ironic-api']['group'] in group_names"
-    - "inventory_hostname == ((groups[ironic_services['ironic-api']['group']]| intersect(ansible_play_hosts)) | list)[0]"
+    - _ironic_api_is_first_play_host
   vars:
     _oslomsg_rpc_setup_host: "{{ ironic_oslomsg_rpc_setup_host }}"
     _oslomsg_rpc_userid: "{{ ironic_oslomsg_rpc_userid }}"
@@ -153,7 +150,7 @@
     _service_users: "{{ ironic_service_user_list }}"
     _service_endpoints: "{{ ironic_service_endpoint_list }}"
     _service_catalog: "{{ ironic_service_catalog_list }}"
-  when: (inventory_hostname == groups['ironic_api'][0] or inventory_hostname == groups['ironic_inspector'][0])
+  when: (_ironic_api_is_first_play_host or _ironic_inspector_is_first_play_host)
   tags:
     - ironic-config
 

vars/main.yml

@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+_ironic_api_is_first_play_host: "{{ (ironic_services['ironic-api']['group'] in group_names and inventory_hostname == (groups[ironic_services['ironic-api']['group']] | intersect(ansible_play_hosts)) | first) | bool }}"
+_ironic_inspector_is_first_play_host: "{{ (ironic_services['ironic-inspector']['group'] in group_names and inventory_hostname == (groups[ironic_services['ironic-inspector']['group']] | intersect(ansible_play_hosts)) | first) | bool }}"
+
 # This special list brings together all of the package installations into one
 # task to save time.