Ensuring the openvswitch_db is ready before creating bridges

Change-Id: I42550c57222de4ad5556e95d40bb96528bc1d085
Closes-Bug: #1533942

ansible/roles/neutron/tasks/start.yml

@@ -16,6 +16,20 @@
        or inventory_hostname in groups['neutron-metadata-agent'])
     - neutron_plugin_agent == "openvswitch"
 
+- name: Waiting the openvswtich_db service to be ready
+  command: docker exec openvswitch_db ovs-vsctl --no-wait show
+  register: check_result
+  until: check_result | success
+  changed_when: False
+  retries: 30
+  delay: 2
+  when:
+    - (inventory_hostname in groups['compute']
+       or inventory_hostname in groups['neutron-dhcp-agent']
+       or inventory_hostname in groups['neutron-l3-agent']
+       or inventory_hostname in groups['neutron-metadata-agent'])
+    - neutron_plugin_agent == "openvswitch"
+
 - name: Ensuring OVS bridge is properly setup
   command: docker exec openvswitch_db /usr/local/bin/kolla_ensure_openvswitch_configured {{ neutron_bridge_name }} {{ neutron_external_interface }}
   register: status