diff --git a/rally/plugins/openstack/context/keystone/users.py b/rally/plugins/openstack/context/keystone/users.py
index c603d22b..98596c94 100644
--- a/rally/plugins/openstack/context/keystone/users.py
+++ b/rally/plugins/openstack/context/keystone/users.py
@@ -55,7 +55,7 @@ CONF.register_opts(USER_CONTEXT_OPTS,
                                       title="benchmark context options"))
 
 
-@context.configure(name="users", order=100)
+@context.configure(name="users", namespace="openstack", order=100)
 class UserGenerator(context.Context):
     """Context class for generating temporary users/tenants for benchmarks."""
 
diff --git a/rally/plugins/openstack/scenario.py b/rally/plugins/openstack/scenario.py
index 86707c35..3f54aae2 100644
--- a/rally/plugins/openstack/scenario.py
+++ b/rally/plugins/openstack/scenario.py
@@ -13,14 +13,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import functools
 import random
 
 from rally import osclients
 from rally.task import scenario
 
-# NOTE(boris-42): Shortcut to remove import of both rally.task.scenario and
-#                 rally.plugins.openstack.scenario
-configure = scenario.configure
+configure = functools.partial(scenario.configure, namespace="openstack")
 
 
 class OpenStackScenario(scenario.Scenario):
@@ -105,3 +104,13 @@ class OpenStackScenario(scenario.Scenario):
         client = getattr(self._admin_clients, client_type)
 
         return client(version) if version is not None else client()
+
+    @classmethod
+    def validate(cls, name, config, admin=None, users=None, deployment=None):
+        if admin:
+            admin = osclients.Clients(admin)
+        if users:
+            users = [osclients.Clients(user["credential"]) for user in users]
+        super(OpenStackScenario, cls).validate(
+            name=name, config=config, admin=admin, users=users,
+            deployment=deployment)
diff --git a/tests/unit/doc/test_task_samples.py b/tests/unit/doc/test_task_samples.py
index 5e315f61..65422ec8 100644
--- a/tests/unit/doc/test_task_samples.py
+++ b/tests/unit/doc/test_task_samples.py
@@ -58,7 +58,7 @@ class TaskSampleTestCase(test.TestCase):
                         task_config = yaml.safe_load(api._Task.render_template
                                                      (task_file.read()))
                         eng = engine.TaskEngine(task_config,
-                                                     mock.MagicMock())
+                                                mock.MagicMock(), mock.Mock())
                         eng.validate()
                     except Exception:
                         print(traceback.format_exc())
diff --git a/tests/unit/plugins/openstack/test_scenario.py b/tests/unit/plugins/openstack/test_scenario.py
index 68741701..aae42e82 100644
--- a/tests/unit/plugins/openstack/test_scenario.py
+++ b/tests/unit/plugins/openstack/test_scenario.py
@@ -127,3 +127,30 @@ class OpenStackScenarioTestCase(test.TestCase):
         self.assertEqual(self.context["tenants"][tenant_id],
                          self.context["tenant"])
         self.assertEqual(expected_tenant_id, tenant_id)
+
+    @mock.patch("rally.task.scenario.Scenario.validate")
+    def test_validate(self, mock_scenario_validate):
+        cred1 = mock.Mock()
+        cred2 = mock.Mock()
+        cred3 = mock.Mock()
+        self.osclients.mock.side_effect = [cred1, cred2, cred3]
+
+        base_scenario.OpenStackScenario.validate(
+            name="foo_name",
+            config="foo_config",
+            admin="foo_admin",
+            users=[{"credential": "foo_user1"},
+                   {"credential": "foo_user2"}],
+            deployment=None)
+
+        mock_scenario_validate.assert_called_once_with(
+            name="foo_name",
+            config="foo_config",
+            admin=cred1,
+            users=[cred2, cred3],
+            deployment=None)
+        self.osclients.mock.assert_has_calls([
+            mock.call("foo_admin"),
+            mock.call("foo_user1"),
+            mock.call("foo_user2"),
+        ])
diff --git a/tests/unit/rally_jobs/test_jobs.py b/tests/unit/rally_jobs/test_jobs.py
index a7ccaab7..6a17846c 100644
--- a/tests/unit/rally_jobs/test_jobs.py
+++ b/tests/unit/rally_jobs/test_jobs.py
@@ -62,7 +62,8 @@ class RallyJobsTestCase(test.TestCase):
                     task = api._Task.render_template(task_file.read(), **args)
                     task = yaml.safe_load(task)
 
-                    eng = engine.TaskEngine(task, mock.MagicMock())
+                    eng = engine.TaskEngine(task, mock.MagicMock(),
+                                            mock.Mock())
                     eng.validate()
                 except Exception:
                     print(traceback.format_exc())