Add ML2/OVN and ML2/OVS setting checks for neutron

It will check the setting of neutron_plugin_agent,
if it is set to "ovn" or "openvswitch", and run
container and volume checks to make sure the other
agent was not already deployed.

Change-Id: Ie00572f3ff9d3500abd5519bd472e2134c318886

ansible/roles/neutron/tasks/deploy.yml

@@ -1,4 +1,6 @@
 ---
+- import_tasks: neutron_plugin_agent_check.yml
+
 - import_tasks: register.yml
 
 - include_tasks: clone.yml

ansible/roles/neutron/tasks/neutron_plugin_agent_check.yml

@@ -0,0 +1,35 @@
+---
+- name: Get container facts
+  become: true
+  kolla_container_facts:
+    container_engine: "{{ kolla_container_engine }}"
+    name:
+      - neutron_openvswitch_agent
+      - ovn_controller
+  check_mode: false
+  register: container_facts
+
+- name: Get container volume facts
+  become: true
+  kolla_container_volume_facts:
+    container_engine: "{{ kolla_container_engine }}"
+    name:
+      - ovn_nb_db
+      - ovn_sb_db
+  check_mode: false
+  register: container_volume_facts
+
+- name: Check for ML2/OVN presence
+  assert:
+    that: neutron_plugin_agent == 'ovn'
+    fail_msg: "ML2/OVN agent detected, neutron_plugin_agent is not set to 'ovn', Kolla-Ansible does not support this migration operation."
+  when: (container_facts['ovn_controller'] is defined) or (container_volume_facts['ovn_nb_db'] is defined) or (container_volume_facts['ovn_sb_db'] is defined)
+
+- name: Check for ML2/OVS presence
+  assert:
+    that:
+      - neutron_plugin_agent == 'openvswitch'
+      - container_volume_facts['ovn_nb_db'] is not defined
+      - container_volume_facts['ovn_sb_db'] is not defined
+    fail_msg: "ML2/OVS agent detected, neutron_plugin_agent is not set to 'openvswitch', Kolla-Ansible does not support this migration operation."
+  when: container_facts['neutron_openvswitch_agent'] is defined

ansible/roles/neutron/tasks/precheck.yml

@@ -53,3 +53,5 @@
   run_once: True
   when:
     - enable_ironic_neutron_agent | bool
+
+- import_tasks: neutron_plugin_agent_check.yml

ansible/roles/neutron/tasks/upgrade.yml

@@ -1,4 +1,6 @@
 ---
+- import_tasks: neutron_plugin_agent_check.yml
+
 - include_tasks: rolling_upgrade.yml
   when: neutron_enable_rolling_upgrade | bool
 

releasenotes/notes/ml2ovs_precheck-c859504004f6884b.yaml

@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    Added a neutron check for ML2/OVS and ML2/OVN presence
+    at the start of deploy phase. It will fail if
+    neutron_plugin_agent is set to ``ovn`` and use of ML2/OVS
+    container detected. In case where neutron_plugin_agent
+    is set to ``openvswitch`` the check will fail when it detects
+    ML2/OVN container or any of the OVN specific volumes.