Request a restart of memcached after a service upgrade after queens

Change-Id: I54b235de947e63e3d7b86ccfdba9f1b968b75650
Closes-Bug: #1828534

src/lib/charm/openstack/designate.py

@@ -643,6 +643,18 @@ class DesignateCharmQueens(DesignateCharm):
                                'config(dns-slaves) or both.')
         return None, None
 
+    def run_upgrade(self, interfaces_list=None):
+        """Upgrade OpenStack if an upgrade is available and action-managed
+           upgrades is not enabled.
+        :param interfaces_list: List of instances of interface classes
+        :returns: None
+        """
+        super(DesignateCharmQueens, self).run_upgrade(
+            interfaces_list=interfaces_list)
+        memcached = relations.endpoint_from_flag(
+            'coordinator-memcached.available')
+        memcached.request_restart()
+
 
 # Inheriting from DesignateCharmQueens allows to keep
 # enforcing nameservers' assignment while changing

unit_tests/test_lib_charm_openstack_designate.py

@@ -362,3 +362,16 @@ class TestDesignateCharm(Helper):
         with designate.DesignateCharm.check_zone_ids('novadom', 'neutrondom'):
             pass
         self.assertFalse(self.leader_set.called)
+
+
+class TestDesignateQueensCharm(Helper):
+
+    def test_upgrade(self):
+        self.patch(designate.DesignateCharm, 'run_upgrade')
+        self.patch(designate.relations, 'endpoint_from_flag')
+        endpoint = mock.MagicMock()
+        self.endpoint_from_flag.return_value = endpoint
+        a = designate.DesignateCharmQueens(release='queens')
+        a.run_upgrade()
+        self.run_upgrade.assert_called_once_with(interfaces_list=None)
+        endpoint.request_restart.assert_called_once_with()