diff --git a/ceilometer/api/controllers/v2/alarms.py b/ceilometer/api/controllers/v2/alarms.py
index 5fdbd00b2d..be015ffa2b 100644
--- a/ceilometer/api/controllers/v2/alarms.py
+++ b/ceilometer/api/controllers/v2/alarms.py
@@ -396,18 +396,20 @@ class Alarm(base.Base):
         auth_plugin = pecan.request.environ.get('keystone.token_auth')
         for actions in (self.ok_actions, self.alarm_actions,
                         self.insufficient_data_actions):
-            for index, action in enumerate(actions[:]):
-                url = netutils.urlsplit(action)
-                if self._is_trust_url(url):
-                    if '@' not in url.netloc:
-                        # We have a trust action without a trust ID, create it
-                        trust_id = keystone_client.create_trust_id(
-                            trustor_user_id, trustor_project_id, roles,
-                            auth_plugin)
-                        netloc = '%s:delete@%s' % (trust_id, url.netloc)
-                        url = list(url)
-                        url[1] = netloc
-                        actions[index] = urlparse.urlunsplit(url)
+            if actions is not None:
+                for index, action in enumerate(actions[:]):
+                    url = netutils.urlsplit(action)
+                    if self._is_trust_url(url):
+                        if '@' not in url.netloc:
+                            # We have a trust action without a trust ID,
+                            # create it
+                            trust_id = keystone_client.create_trust_id(
+                                trustor_user_id, trustor_project_id, roles,
+                                auth_plugin)
+                            netloc = '%s:delete@%s' % (trust_id, url.netloc)
+                            url = list(url)
+                            url[1] = netloc
+                            actions[index] = urlparse.urlunsplit(url)
         if old_alarm:
             for key in ('ok_actions', 'alarm_actions',
                         'insufficient_data_actions'):
diff --git a/ceilometer/tests/api/v2/test_alarm_scenarios.py b/ceilometer/tests/api/v2/test_alarm_scenarios.py
index eb0c396397..47993508ee 100644
--- a/ceilometer/tests/api/v2/test_alarm_scenarios.py
+++ b/ceilometer/tests/api/v2/test_alarm_scenarios.py
@@ -1782,6 +1782,30 @@ class TestAlarms(v2.FunctionalTest,
         self.assertEqual(['test://', 'log://'],
                          alarms[0].alarm_actions)
 
+    def test_post_alarm_without_actions(self):
+        body = {
+            'name': 'alarm_actions_none',
+            'type': 'combination',
+            'combination_rule': {
+                'alarm_ids': ['a', 'b'],
+            },
+            'alarm_actions': None
+        }
+        headers = self.auth_headers
+        headers['X-Roles'] = 'admin'
+        self.post_json('/alarms', params=body, status=201,
+                       headers=headers)
+        alarms = list(self.alarm_conn.get_alarms(name='alarm_actions_none'))
+        self.assertEqual(1, len(alarms))
+
+        # FIXME(sileht): This should really returns [] not None
+        # but the mongodb and sql just store the json dict as is...
+        # migration script for sql will be a mess because we have
+        # to parse all JSON :(
+        # I guess we assume that wsme convert the None input to []
+        # because of the array type, but it won't...
+        self.assertIsNone(alarms[0].alarm_actions)
+
     def test_post_alarm_trust(self):
         json = {
             'name': 'added_alarm_defaults',