Move mDNS to network nodes

mDNS publish DNS services to designate service customers.
Only network node should be reachable by public networks.

Change-Id: Id2947df89d2d831d67e006a581ac88b4ecf8ce04
Closes-Bug: #1693918

ansible/inventory/all-in-one

@@ -521,7 +521,7 @@ designate
 designate
 
 [designate-mdns:children]
-designate
+network
 
 [designate-worker:children]
 designate

ansible/inventory/multinode

@@ -539,7 +539,7 @@ designate
 designate
 
 [designate-mdns:children]
-designate
+network
 
 [designate-worker:children]
 designate

ansible/roles/designate/templates/designate.conf.j2

@@ -39,9 +39,11 @@ memcached_servers = {% for host in groups['memcached'] %}{{ hostvars[host]['ansi
 enabled_notification_handlers = nova_fixed, neutron_floatingip
 workers = {{ openstack_service_workers }}
 
+{% if service_name == 'designate-mdns' %}
 [service:mdns]
 listen = {{ hostvars[inventory_hostname]['ansible_' + dns_interface]['ipv4']['address'] }}:{{ designate_mdns_port }}
 workers = {{ openstack_service_workers }}
+{% endif %}
 
 [service:worker]
 enabled = True

releasenotes/notes/mdns-network-nodes-ac8b9d4b721e9ac8.yaml

+---
+upgrade:
+  - |
+    Designate mDNS container now runs on network nodes,
+    ensure designate-mdns group in your inventory has network
+    as parent group.