Disable dhcp-agent and metadata-agent for OVN

OVN doesn't need the neutron-metadata-agent and
neutron-dhcp-agent service.

Change-Id: I58e94199a32ad300b3f70861dc7804f34518c8c2

releasenotes/notes/ovn_dhcp_metadata_agents-851b42a6923c811f.yaml

@@ -0,0 +1,10 @@
+---
+
+fixes:
+  - |
+    Fixed issue where neutron-metadata-agent and neutron-dhcp-agent were
+    started on network_hosts for OVN scenario along with
+    neutron-ovn-metadata-agent. These services will be disabled and masked
+    for existing environments. Manual clean-up of systemd services and
+    correpsonsive neutron agents is still needed.
+    New deployments won't have these services deployed from the beginning.

tasks/main.yml

@@ -157,6 +157,30 @@
   tags:
     - neutron-config
 
+# TODO(noonedeadpunk): Remove block for Bobcat release
+- name: Disable dhcp and metadata agents for OVN scenario
+  when:
+    - neutron_plugin_type == 'ml2.ovn'
+    - (neutron_services['neutron-metadata-agent']['group'] in group_names) or (neutron_services['neutron-dhcp-agent']['group'] in group_names)
+  block:
+    - name: Gather service facts
+      service_facts:
+
+    - name: Disable services if they present
+      service:
+        name: "{{ item['service_name'] }}"
+        state: stopped
+        enabled: False
+        masked: True
+      when:
+        - item['group'] in group_names
+        - item['service_name'] ~ '.service' in ansible_facts.services
+      notify:
+        - "Restart neutron services"
+      with_items:
+        - "{{ neutron_services['neutron-metadata-agent'] }}"
+        - "{{ neutron_services['neutron-dhcp-agent'] }}"
+
 - name: Run the systemd service role
   import_role:
     name: systemd_service

vars/main.yml

@@ -279,13 +279,13 @@ neutron_l3: "{% if 'router' in neutron_plugin_base or 'neutron.services.l3_route
 ### DHCP Agent Plugin Configuration
 ###
 
-neutron_dhcp: "{% if neutron_plugin_type.split('.')[0] == 'ml2' %}True{% else %}False{% endif %}"
+neutron_dhcp: "{% if (neutron_plugin_type.split('.')[0] == 'ml2') and  (neutron_plugin_type != 'ml2.ovn') %}True{% else %}False{% endif %}"
 
 ###
 ### Metadata Agent Plugin Configuration
 ###
 
-neutron_metadata: "{% if neutron_plugin_type.split('.')[0] == 'ml2' %}True{% else %}False{% endif %}"
+neutron_metadata: "{% if (neutron_plugin_type.split('.')[0] == 'ml2') and (neutron_plugin_type != 'ml2.ovn') %}True{% else %}False{% endif %}"
 
 ###
 ### FWaaS Plugin Configuration