diff --git a/magnum/api/validation.py b/magnum/api/validation.py
index c17c673cd6..dd87ba90d2 100644
--- a/magnum/api/validation.py
+++ b/magnum/api/validation.py
@@ -94,8 +94,12 @@ def enforce_cluster_master_size_supported():
     @decorator.decorator
     def wrapper(func, *args, **kwargs):
         cluster = args[1]
-        cluster_driver = driver.Driver.get_driver_for_cluster(
-            pecan.request.context, cluster)
+        cluster_template = objects.ClusterTemplate.get(
+            pecan.request.context, cluster.cluster_template_id)
+        cluster_type = (cluster_template.server_type,
+                        cluster_template.cluster_distro,
+                        cluster_template.coe)
+        cluster_driver = driver.Driver.get_driver(*cluster_type)
         # Call into the driver to validate initial master size
         cluster_driver.validate_master_size(cluster.master_count)
         return func(*args, **kwargs)
diff --git a/magnum/tests/unit/api/controllers/v1/test_cluster.py b/magnum/tests/unit/api/controllers/v1/test_cluster.py
index 60f8f6c6ce..5e70ea9a12 100644
--- a/magnum/tests/unit/api/controllers/v1/test_cluster.py
+++ b/magnum/tests/unit/api/controllers/v1/test_cluster.py
@@ -706,10 +706,10 @@ def test_create_cluster_with_non_existent_cluster_template_name(self):
         self.assertEqual(400, response.status_int)
         self.assertTrue(response.json['errors'])
 
-    def test_create_cluster_with_cluster_template_name(self):
+    def test_create_cluster_with_cluster_template_name_as_id(self):
         modelname = self.cluster_template.name
-        bdict = apiutils.cluster_post_data(name=modelname)
-        response = self.post_json('/clusters', bdict, expect_errors=True)
+        bdict = apiutils.cluster_post_data(cluster_template_id=modelname)
+        response = self.post_json('/clusters', bdict)
         self.assertEqual('application/json', response.content_type)
         self.assertEqual(202, response.status_int)