Workaround: stop bifrost services before seed upgrade

This avoids mariadb being ungracefully shut down, which prevents it from
being started again.

This should be reverted once bug 1834332 has been fixed in kolla ansible
stein.

Change-Id: Ic3932d4af5c0a7639dfeb6cda7e1cd3f61d287c6
Story: 2006050
Task: 34743

ansible/seed-service-upgrade-prep.yml

@@ -46,3 +46,17 @@
             ironic-dbsync online_data_migrations
         fi'
       changed_when: true
+
+    # TODO(mgoddard): Remove this once bug 1834332 is fixed in kolla-ansible.
+    # Ensure that all services are stopped gracefully, and in a sensible
+    # order.
+    - name: Stop services gracefully
+      command: docker exec bifrost_deploy systemctl stop {{ item }}.service
+      with_items:
+        - ironic-api
+        - ironic-conductor
+        - ironic-inspector
+        - mariadb
+        - rabbitmq-server
+        - nginx
+      changed_when: true