commit a969b5ee7742d28c77df48bd89999c675bbe839a
Author: Dmitriy Rabotyagov <dmitriy.rabotyagov@citynetwork.eu>
Date:   Fri Sep 11 15:00:25 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: I6f1937c329292028e772fbe96d2466000726e4b7

diff --git a/tasks/main.yml b/tasks/main.yml
index 52c8975..f1f2119 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -28,7 +28,7 @@
 
 - import_tasks: db_setup.yml
   when:
-    - "inventory_hostname == ((groups['blazar_all'] | intersect(ansible_play_hosts)) | list)[0]"
+    - _blazar_is_first_play_host
   vars:
     _oslodb_setup_host: "{{ blazar_db_setup_host }}"
     _oslodb_ansible_python_interpreter: "{{ blazar_db_setup_python_interpreter }}"
@@ -45,7 +45,7 @@
 
 - import_tasks: mq_setup.yml
   when:
-    - "inventory_hostname == ((groups['blazar_all'] | intersect(ansible_play_hosts)) | list)[0]"
+    - _blazar_is_first_play_host
   vars:
     _oslomsg_rpc_setup_host: "{{ blazar_oslomsg_rpc_setup_host }}"
     _oslomsg_rpc_userid: "{{ blazar_oslomsg_rpc_userid }}"
@@ -88,7 +88,7 @@
 
 - import_tasks: blazar_db_setup.yml
   when:
-    - "inventory_hostname == ((groups['blazar_all'] | intersect(ansible_play_hosts)) | list)[0]"
+    - _blazar_is_first_play_host
   tags:
     - blazar-config
 
@@ -137,6 +137,6 @@
         type: "{{ blazar_service_type }}"
         description: "{{ blazar_service_description }}"
   when:
-    - "inventory_hostname == ((groups['blazar_all'] | intersect(ansible_play_hosts)) | list)[0]"
+    - _blazar_is_first_play_host
   tags:
     - blazar-config
diff --git a/vars/main.yml b/vars/main.yml
index 6f324b7..738db91 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.
 
+_blazar_is_first_play_host: "{{ (blazar_services['blazar-api']['group'] in group_names and inventory_hostname == ((groups[blazar_services['blazar-api']['group']] | intersect(ansible_play_hosts)) | list)[0]) | bool }}"
+
 #
 # Compile a list of the services on a host based on whether
 # the host is in the host group and the service is enabled.