diff --git a/rally/plugins/openstack/platforms/existing.py b/rally/plugins/openstack/platforms/existing.py
index bb5336ed..592e2b05 100644
--- a/rally/plugins/openstack/platforms/existing.py
+++ b/rally/plugins/openstack/platforms/existing.py
@@ -13,7 +13,8 @@
 #    under the License.
 
 import copy
-import sys
+import json
+import traceback
 
 from rally.common import logging
 from rally.env import platform
@@ -145,21 +146,28 @@ class OpenStack(platform.Platform):
                 osclients.Clients(
                     self.platform_data["admin"]).verified_keystone()
             except Exception:
+                d = copy.deepcopy(self.platform_data["admin"])
+                d["password"] = "***"
                 return {
                     "available": False,
-                    "message": ("Bad admin creds: %s"
-                                % self.platform_data["admin"]),
-                    "traceback": list(sys.exc_info())
+                    "message": (
+                        "Bad admin creds: \n%s"
+                        % json.dumps(d, indent=2, sort_keys=True)),
+                    "traceback": traceback.format_exc()
                 }
 
         for user in self.platform_data["users"]:
             try:
                 osclients.Clients(user).keystone()
             except Exception:
+                d = copy.deepcopy(user)
+                d["password"] = "***"
                 return {
                     "available": False,
-                    "message": ("Bad user creds: %s" % user),
-                    "traceback": list(sys.exc_info())
+                    "message": (
+                        "Bad user creds: \n%s"
+                        % json.dumps(d, indent=2, sort_keys=True)),
+                    "traceback": traceback.format_exc()
                 }
 
         return {"available": True}
@@ -168,9 +176,10 @@ class OpenStack(platform.Platform):
         """Return information about cloud as dict."""
         active_user = (self.platform_data["admin"] or
                        self.platform_data["users"][0])
+        services = osclients.Clients(active_user).services()
         return {
             "info": {
-                "services": osclients.Clients(active_user).list_services()
+                "services": services
             }
         }
 
diff --git a/tests/unit/plugins/openstack/platforms/test_existing.py b/tests/unit/plugins/openstack/platforms/test_existing.py
index 4adb915e..e2bfaad0 100644
--- a/tests/unit/plugins/openstack/platforms/test_existing.py
+++ b/tests/unit/plugins/openstack/platforms/test_existing.py
@@ -12,6 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import json
+
 import mock
 
 from rally.env import platform
@@ -160,35 +162,47 @@ class ExistingPlatformTestCase(test_platform.PlatformBaseTestCase):
     @mock.patch("rally.plugins.openstack.osclients.Clients")
     def test_check_failed_admin(self, mock_clients):
         mock_clients.return_value.verified_keystone.side_effect = Exception
-        pdata = {"admin": mock.MagicMock()}
+        pdata = {"admin": {"username": "balbab", "password": "12345"}}
         result = existing.OpenStack({}, platform_data=pdata).check_health()
         self._check_health_schema(result)
         self.assertEqual(
             {"available": False,
-             "message": "Bad admin creds: %s" % pdata["admin"],
-             "traceback": [Exception, mock.ANY, mock.ANY]},
+             "message":
+                "Bad admin creds: \n%s"
+                % json.dumps({"username": "balbab", "password": "***"},
+                             indent=2, sort_keys=True),
+             "traceback": mock.ANY},
             result)
+        self.assertIn("Traceback (most recent call last)", result["traceback"])
 
     @mock.patch("rally.plugins.openstack.osclients.Clients")
     def test_check_failed_users(self, mock_clients):
         mock_clients.return_value.keystone.side_effect = Exception
-        pdata = {"admin": None, "users": [mock.MagicMock()]}
+        pdata = {"admin": None,
+                 "users": [{"username": "balbab", "password": "12345"}]}
         result = existing.OpenStack({}, platform_data=pdata).check_health()
         self._check_health_schema(result)
         self.assertEqual(
             {"available": False,
-             "message": "Bad user creds: %s" % pdata["users"][0],
-             "traceback": [Exception, mock.ANY, mock.ANY]},
+             "message":
+                "Bad user creds: \n%s"
+                % json.dumps({"username": "balbab", "password": "***"},
+                             indent=2, sort_keys=True),
+             "traceback": mock.ANY},
             result)
+        self.assertIn("Traceback (most recent call last)", result["traceback"])
 
     @mock.patch("rally.plugins.openstack.osclients.Clients")
     def test_info(self, mock_clients):
-        mock_clients.return_value.list_services.return_value = ["a", "b"]
-        p = existing.OpenStack({},
-                               platform_data={"admin": None, "users": ["u1"]})
+        mock_clients.return_value.services.return_value = ["a", "b"]
+        platform_data = {
+            "admin": None,
+            "users": [{"username": "u1", "password": "123"}]
+        }
+        p = existing.OpenStack({}, platform_data=platform_data)
 
         result = p.info()
-        mock_clients.assert_called_once_with("u1")
-        mock_clients.return_value.list_services.assert_called_once_with()
+        mock_clients.assert_called_once_with(platform_data["users"][0])
+        mock_clients.return_value.services.assert_called_once_with()
         self.assertEqual({"info": {"services": ["a", "b"]}}, result)
         self._check_info_schema(result)