diff --git a/heat/engine/resources/openstack/zaqar/subscription.py b/heat/engine/resources/openstack/zaqar/subscription.py
index 94cc6ea134..622df53bdf 100644
--- a/heat/engine/resources/openstack/zaqar/subscription.py
+++ b/heat/engine/resources/openstack/zaqar/subscription.py
@@ -193,7 +193,9 @@ class MistralTrigger(ZaqarSubscription):
 
     def _subscriber_url(self):
         mistral_client = self.client('mistral')
-        return 'trust+%s/executions' % mistral_client.http_client.base_url
+        manager = getattr(mistral_client.executions, 'client',
+                          mistral_client.executions)
+        return 'trust+%s/executions' % manager.http_client.base_url
 
     def _subscription_options(self):
         params = dict(self.properties[self.PARAMS])
diff --git a/heat/tests/openstack/zaqar/test_subscription.py b/heat/tests/openstack/zaqar/test_subscription.py
index 85cf09bf17..a9e93f046f 100644
--- a/heat/tests/openstack/zaqar/test_subscription.py
+++ b/heat/tests/openstack/zaqar/test_subscription.py
@@ -348,8 +348,10 @@ class ZaqarMistralTriggerTest(common.HeatTestCase):
         def client(name='zaqar'):
             if name == 'mistral':
                 client = mock.Mock()
-                client.http_client = mock.Mock()
-                client.http_client.base_url = 'http://mistral.example.net:8989'
+                http_client = mock.Mock()
+                client.executions = mock.Mock(spec=['http_client'])
+                client.executions.http_client = http_client
+                http_client.base_url = 'http://mistral.example.net:8989'
                 return client
             elif name == 'zaqar':
                 return self.fc