Merge "Add precheck for ceilometer backend"

ansible/roles/ceilometer/tasks/bootstrap.yml

 ---
+- name: Checking backend for ceilometer
+  local_action: fail msg="No backend enabled for ceilometer. Mongodb is the only supported one for now"
+  changed_when: false
+  when: enable_ceilometer | bool and not enable_mongodb | bool
+
 - name: Creating Ceilometer database
   command: docker exec -t mongodb mongo --host {{ ceilometer_database_address }} --eval 'db = db.getSiblingDB("{{ ceilometer_database_name }}"); db.addUser({user':' "{{ ceilometer_database_user }}", pwd':' "{{ ceilometer_database_password}}", roles':' [ "readWrite", "dbAdmin" ]})'
   register: database

ansible/roles/prechecks/tasks/service_checks.yml

@@ -56,3 +56,8 @@
     - enable_neutron_agent_ha | bool
     - groups['neutron-dhcp-agent'] | length < 2
       or groups['neutron-l3-agent'] | length < 2
+
+- name: Checking backend for ceilometer
+  local_action: fail msg="No backend enabled for ceilometer. Mongodb is the only supported one for now"
+  changed_when: false
+  when: enable_ceilometer | bool and not enable_mongodb | bool