diff --git a/kolla/template/methods.py b/kolla/template/methods.py
index 66c5dcfa96..fb470a65f7 100644
--- a/kolla/template/methods.py
+++ b/kolla/template/methods.py
@@ -88,6 +88,9 @@ def handle_repos(context, reponames, mode):
     else:
         raise KeyError
 
+    if not isinstance(reponames, list):
+        raise TypeError("First argument should be a list of repositories")
+
     repofile = os.path.dirname(os.path.realpath(__file__)) + '/repos.yaml'
     with open(repofile, 'r') as repos_file:
         repo_data = {}
diff --git a/kolla/tests/test_methods.py b/kolla/tests/test_methods.py
index d2f6eff9dc..c33aba7f9b 100644
--- a/kolla/tests/test_methods.py
+++ b/kolla/tests/test_methods.py
@@ -150,3 +150,16 @@ class MethodsTest(base.TestCase):
         result = methods.handle_repos(template_vars, ['grafana'], 'disable')
         expectCmd = ''
         self.assertEqual(expectCmd, result)
+
+    def test_handle_repos_string(self):
+        template_vars = {
+            'base_arch': 'x86_64',
+            'base_distro': 'debian',
+            'base_package_type': 'deb'
+        }
+
+        self.assertRaisesRegex(TypeError,
+                               r'First argument should be a list of '
+                               r'repositories',
+                               methods.handle_repos, template_vars, 'grafana',
+                               'disable')