diff --git a/tempest/api/volume/test_availability_zone.py b/tempest/api/volume/test_availability_zone.py
index 1db7b7b..fe8f96e 100644
--- a/tempest/api/volume/test_availability_zone.py
+++ b/tempest/api/volume/test_availability_zone.py
@@ -22,6 +22,7 @@
     """
     Tests Availability Zone API List
     """
+    _interface = 'json'
 
     @classmethod
     def setUpClass(cls):