diff --git a/nova/compute/api.py b/nova/compute/api.py
index b248cac1c35b..8ec554c5510b 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -4070,7 +4070,7 @@ class API(base.Base):
 
     @check_instance_lock
     @check_instance_state(vm_state=[vm_states.ACTIVE])
-    def set_admin_password(self, context, instance, password=None):
+    def set_admin_password(self, context, instance, password):
         """Set the root/admin password for the given instance.
 
         @param context: Nova auth context.
diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index fb799894391e..81c7ee51b0ae 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -3949,10 +3949,6 @@ class ComputeManager(manager.Manager):
         """
 
         context = context.elevated()
-        if new_pass is None:
-            # Generate a random password
-            new_pass = utils.generate_password()
-
         current_power_state = self._get_power_state(context, instance)
         expected_state = power_state.RUNNING
 
diff --git a/nova/tests/unit/api/openstack/compute/test_admin_password.py b/nova/tests/unit/api/openstack/compute/test_admin_password.py
index 0a274b243674..c23b9a73453d 100644
--- a/nova/tests/unit/api/openstack/compute/test_admin_password.py
+++ b/nova/tests/unit/api/openstack/compute/test_admin_password.py
@@ -14,6 +14,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 import mock
+import six
 import webob
 
 from nova.api.openstack.compute import admin_password as admin_password_v21
@@ -122,9 +123,11 @@ class AdminPasswordTestV21(test.NoDBTestCase):
 
     def test_change_password_none(self):
         body = {'changePassword': {'adminPass': None}}
-        self.assertRaises(self.validation_error,
-                          self._get_action(),
-                          self.fake_req, fakes.FAKE_UUID, body=body)
+        ex = self.assertRaises(self.validation_error,
+                               self._get_action(),
+                               self.fake_req, fakes.FAKE_UUID, body=body)
+        self.assertIn('adminPass. Value: None. None is not of type',
+                      six.text_type(ex))
 
     def test_change_password_adminpass_none(self):
         body = {'changePassword': None}
diff --git a/nova/tests/unit/compute/test_compute_api.py b/nova/tests/unit/compute/test_compute_api.py
index 51d5a751c6d5..448115fc9db7 100644
--- a/nova/tests/unit/compute/test_compute_api.py
+++ b/nova/tests/unit/compute/test_compute_api.py
@@ -4970,14 +4970,14 @@ class _ComputeAPIUnitTestMixIn(object):
                            'set_admin_password')
         def do_test(compute_rpcapi_mock, record_mock, instance_save_mock):
             # call the API
-            self.compute_api.set_admin_password(self.context, instance)
+            self.compute_api.set_admin_password(self.context, instance, 'pass')
             # make our assertions
             instance_save_mock.assert_called_once_with(
                 expected_task_state=[None])
             record_mock.assert_called_once_with(
                 self.context, instance, instance_actions.CHANGE_PASSWORD)
             compute_rpcapi_mock.assert_called_once_with(
-                self.context, instance=instance, new_pass=None)
+                self.context, instance=instance, new_pass='pass')
 
         do_test()
 
diff --git a/nova/tests/unit/compute/test_compute_mgr.py b/nova/tests/unit/compute/test_compute_mgr.py
index e6290db7ffcc..348169e7bd43 100644
--- a/nova/tests/unit/compute/test_compute_mgr.py
+++ b/nova/tests/unit/compute/test_compute_mgr.py
@@ -4369,9 +4369,7 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase,
     @mock.patch('nova.compute.manager.ComputeManager._get_power_state',
                 return_value=power_state.RUNNING)
     @mock.patch.object(objects.Instance, 'save')
-    @mock.patch('nova.utils.generate_password', return_value='fake-pass')
-    def test_set_admin_password(self, gen_password_mock, instance_save_mock,
-                                power_state_mock):
+    def test_set_admin_password(self, instance_save_mock, power_state_mock):
         # Ensure instance can have its admin password set.
         instance = fake_instance.fake_instance_obj(
             self.context,
@@ -4382,7 +4380,8 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase,
         @mock.patch.object(self.compute.driver, 'set_admin_password')
         def do_test(driver_mock, elevated_mock):
             # call the manager method
-            self.compute.set_admin_password(self.context, instance, None)
+            self.compute.set_admin_password(self.context, instance,
+                                            'fake-pass')
             # make our assertions
             self.assertEqual(vm_states.ACTIVE, instance.vm_state)
             self.assertIsNone(instance.task_state)