diff --git a/requirements.txt b/requirements.txt
index 94c6fb0..ebb23c3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,7 +11,7 @@
 netaddr>=0.7.12
 python-ceilometerclient>=1.0.6
 python-glanceclient>=0.15.0
-python-keystoneclient>=1.0.0
+python-keystoneclient>=1.1.0
 python-novaclient>=2.18.0
 python-neutronclient>=2.3.6,<3
 python-cinderclient>=1.1.0
@@ -25,4 +25,4 @@
 iso8601>=0.1.9
 fixtures>=0.3.14
 testscenarios>=0.4
-tempest-lib>=0.1.0
+tempest-lib>=0.2.0
diff --git a/tempest/api/compute/admin/test_flavors_negative.py b/tempest/api/compute/admin/test_flavors_negative.py
index 34d8e3f..d1060c5 100644
--- a/tempest/api/compute/admin/test_flavors_negative.py
+++ b/tempest/api/compute/admin/test_flavors_negative.py
@@ -106,6 +106,5 @@
 @test.SimpleNegativeAutoTest
 class FlavorCreateNegativeTestJSON(base.BaseV2ComputeAdminTest,
                                    test.NegativeAutoTest):
-    _interface = 'json'
     _service = CONF.compute.catalog_type
     _schema = flavors.flavor_create
diff --git a/tempest/api/compute/base.py b/tempest/api/compute/base.py
index 21e342a..4120a9a 100644
--- a/tempest/api/compute/base.py
+++ b/tempest/api/compute/base.py
@@ -329,20 +329,17 @@
 
 class BaseV2ComputeTest(BaseComputeTest):
     _api_version = 2
-    _interface = "json"
 
 
 class BaseComputeAdminTest(BaseComputeTest):
     """Base test case class for Compute Admin API tests."""
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
         super(BaseComputeAdminTest, cls).resource_setup()
         try:
             creds = cls.isolated_creds.get_admin_creds()
-            cls.os_adm = clients.Manager(
-                credentials=creds, interface=cls._interface)
+            cls.os_adm = clients.Manager(credentials=creds)
         except NotImplementedError:
             msg = ("Missing Compute Admin API credentials in configuration.")
             raise cls.skipException(msg)
diff --git a/tempest/api/compute/images/test_list_image_filters.py b/tempest/api/compute/images/test_list_image_filters.py
index 0d3fe7d..a2e5f56 100644
--- a/tempest/api/compute/images/test_list_image_filters.py
+++ b/tempest/api/compute/images/test_list_image_filters.py
@@ -172,8 +172,6 @@
         # Verify only the expected number of results are returned
         params = {'limit': '1'}
         images = self.client.list_images(params)
-        # when _interface='xml', one element for images_links in images
-        # ref: Question #224349
         self.assertEqual(1, len([x for x in images if 'id' in x]))
 
     @test.attr(type='gate')
diff --git a/tempest/api/compute/servers/test_list_servers_negative.py b/tempest/api/compute/servers/test_list_servers_negative.py
index a017f5f..3827ad9 100644
--- a/tempest/api/compute/servers/test_list_servers_negative.py
+++ b/tempest/api/compute/servers/test_list_servers_negative.py
@@ -101,7 +101,6 @@
         # List servers by specifying limits
         resp, body = self.client.list_servers({'limit': 1})
         self.assertEqual('200', resp['status'])
-        # when _interface='xml', one element for servers_links in servers
         self.assertEqual(1, len([x for x in body['servers'] if 'id' in x]))
 
     @test.attr(type=['negative', 'gate'])
diff --git a/tempest/api/compute/volumes/test_volumes_get.py b/tempest/api/compute/volumes/test_volumes_get.py
index 53f5ac0..69998d2 100644
--- a/tempest/api/compute/volumes/test_volumes_get.py
+++ b/tempest/api/compute/volumes/test_volumes_get.py
@@ -38,7 +38,7 @@
     def test_volume_create_get_delete(self):
         # CREATE, GET, DELETE Volume
         volume = None
-        v_name = data_utils.rand_name('Volume-%s-') % self._interface
+        v_name = data_utils.rand_name('Volume')
         metadata = {'Type': 'work'}
         # Create volume
         volume = self.client.create_volume(size=1,
diff --git a/tempest/api/compute/volumes/test_volumes_list.py b/tempest/api/compute/volumes/test_volumes_list.py
index c0ac99b..ba7ee6b 100644
--- a/tempest/api/compute/volumes/test_volumes_list.py
+++ b/tempest/api/compute/volumes/test_volumes_list.py
@@ -42,7 +42,7 @@
         cls.volume_list = []
         cls.volume_id_list = []
         for i in range(3):
-            v_name = data_utils.rand_name('volume-%s' % cls._interface)
+            v_name = data_utils.rand_name('volume')
             metadata = {'Type': 'work'}
             try:
                 volume = cls.client.create_volume(size=1,
diff --git a/tempest/api/data_processing/base.py b/tempest/api/data_processing/base.py
index 4c53a57..5992921 100644
--- a/tempest/api/data_processing/base.py
+++ b/tempest/api/data_processing/base.py
@@ -22,16 +22,26 @@
 
 
 class BaseDataProcessingTest(tempest.test.BaseTestCase):
-    _interface = 'json'
+
+    @classmethod
+    def skip_checks(cls):
+        super(BaseDataProcessingTest, cls).skip_checks()
+        if not CONF.service_available.sahara:
+            raise cls.skipException('Sahara support is required')
+
+    @classmethod
+    def setup_credentials(cls):
+        super(BaseDataProcessingTest, cls).setup_credentials()
+        cls.os = cls.get_client_manager()
+
+    @classmethod
+    def setup_clients(cls):
+        super(BaseDataProcessingTest, cls).setup_clients()
+        cls.client = cls.os.data_processing_client
 
     @classmethod
     def resource_setup(cls):
         super(BaseDataProcessingTest, cls).resource_setup()
-        if not CONF.service_available.sahara:
-            raise cls.skipException('Sahara support is required')
-
-        cls.os = cls.get_client_manager()
-        cls.client = cls.os.data_processing_client
 
         cls.flavor_ref = CONF.compute.flavor_ref
 
diff --git a/tempest/api/database/base.py b/tempest/api/database/base.py
index dd4c684..31c5d2a 100644
--- a/tempest/api/database/base.py
+++ b/tempest/api/database/base.py
@@ -24,22 +24,30 @@
 class BaseDatabaseTest(tempest.test.BaseTestCase):
     """Base test case class for all Database API tests."""
 
-    _interface = 'json'
-
     @classmethod
-    def resource_setup(cls):
-        super(BaseDatabaseTest, cls).resource_setup()
+    def skip_checks(cls):
+        super(BaseDatabaseTest, cls).skip_checks()
         if not CONF.service_available.trove:
             skip_msg = ("%s skipped as trove is not available" % cls.__name__)
             raise cls.skipException(skip_msg)
 
-        cls.catalog_type = CONF.database.catalog_type
-        cls.db_flavor_ref = CONF.database.db_flavor_ref
-        cls.db_current_version = CONF.database.db_current_version
+    @classmethod
+    def setup_credentials(cls):
+        super(BaseDatabaseTest, cls).setup_credentials()
+        cls.os = cls.get_client_manager()
 
-        os = cls.get_client_manager()
-        cls.os = os
+    @classmethod
+    def setup_clients(cls):
+        super(BaseDatabaseTest, cls).setup_clients()
         cls.database_flavors_client = cls.os.database_flavors_client
         cls.os_flavors_client = cls.os.flavors_client
         cls.database_limits_client = cls.os.database_limits_client
         cls.database_versions_client = cls.os.database_versions_client
+
+    @classmethod
+    def resource_setup(cls):
+        super(BaseDatabaseTest, cls).resource_setup()
+
+        cls.catalog_type = CONF.database.catalog_type
+        cls.db_flavor_ref = CONF.database.db_flavor_ref
+        cls.db_current_version = CONF.database.db_current_version
diff --git a/tempest/api/database/flavors/test_flavors.py b/tempest/api/database/flavors/test_flavors.py
index ed172e9..bb7035b 100644
--- a/tempest/api/database/flavors/test_flavors.py
+++ b/tempest/api/database/flavors/test_flavors.py
@@ -20,8 +20,8 @@
 class DatabaseFlavorsTest(base.BaseDatabaseTest):
 
     @classmethod
-    def resource_setup(cls):
-        super(DatabaseFlavorsTest, cls).resource_setup()
+    def setup_clients(cls):
+        super(DatabaseFlavorsTest, cls).setup_clients()
         cls.client = cls.database_flavors_client
 
     @test.attr(type='smoke')
diff --git a/tempest/api/database/flavors/test_flavors_negative.py b/tempest/api/database/flavors/test_flavors_negative.py
index c6acacf..bb9c05d 100644
--- a/tempest/api/database/flavors/test_flavors_negative.py
+++ b/tempest/api/database/flavors/test_flavors_negative.py
@@ -22,8 +22,8 @@
 class DatabaseFlavorsNegativeTest(base.BaseDatabaseTest):
 
     @classmethod
-    def resource_setup(cls):
-        super(DatabaseFlavorsNegativeTest, cls).resource_setup()
+    def setup_clients(cls):
+        super(DatabaseFlavorsNegativeTest, cls).setup_clients()
         cls.client = cls.database_flavors_client
 
     @test.attr(type=['negative', 'gate'])
diff --git a/tempest/api/database/limits/test_limits.py b/tempest/api/database/limits/test_limits.py
index 30d0a77..68a3884 100644
--- a/tempest/api/database/limits/test_limits.py
+++ b/tempest/api/database/limits/test_limits.py
@@ -18,7 +18,6 @@
 
 
 class DatabaseLimitsTest(base.BaseDatabaseTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/database/versions/test_versions.py b/tempest/api/database/versions/test_versions.py
index 80fcecf..37a7407 100644
--- a/tempest/api/database/versions/test_versions.py
+++ b/tempest/api/database/versions/test_versions.py
@@ -18,11 +18,10 @@
 
 
 class DatabaseVersionsTest(base.BaseDatabaseTest):
-    _interface = 'json'
 
     @classmethod
-    def resource_setup(cls):
-        super(DatabaseVersionsTest, cls).resource_setup()
+    def setup_clients(cls):
+        super(DatabaseVersionsTest, cls).setup_clients()
         cls.client = cls.database_versions_client
 
     @test.attr(type='smoke')
diff --git a/tempest/api/identity/admin/test_roles.py b/tempest/api/identity/admin/test_roles.py
index c6c7dc3..80ad6db 100644
--- a/tempest/api/identity/admin/test_roles.py
+++ b/tempest/api/identity/admin/test_roles.py
@@ -21,7 +21,6 @@
 
 
 class RolesTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/test_roles_negative.py b/tempest/api/identity/admin/test_roles_negative.py
index 789e8b6..2c51715 100644
--- a/tempest/api/identity/admin/test_roles_negative.py
+++ b/tempest/api/identity/admin/test_roles_negative.py
@@ -23,7 +23,6 @@
 
 
 class RolesNegativeTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     def _get_role_params(self):
         self.data.setup_test_user()
diff --git a/tempest/api/identity/admin/test_services.py b/tempest/api/identity/admin/test_services.py
index 30e0058..af38afc 100644
--- a/tempest/api/identity/admin/test_services.py
+++ b/tempest/api/identity/admin/test_services.py
@@ -22,7 +22,6 @@
 
 
 class ServicesTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     def _del_service(self, service_id):
         # Deleting the service created in this method
diff --git a/tempest/api/identity/admin/test_tenant_negative.py b/tempest/api/identity/admin/test_tenant_negative.py
index a4bf263..16ea96a 100644
--- a/tempest/api/identity/admin/test_tenant_negative.py
+++ b/tempest/api/identity/admin/test_tenant_negative.py
@@ -23,7 +23,6 @@
 
 
 class TenantsNegativeTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @test.attr(type=['negative', 'gate'])
     def test_list_tenants_by_unauthorized_user(self):
diff --git a/tempest/api/identity/admin/test_tenants.py b/tempest/api/identity/admin/test_tenants.py
index 549e952..cfae3a1 100644
--- a/tempest/api/identity/admin/test_tenants.py
+++ b/tempest/api/identity/admin/test_tenants.py
@@ -21,7 +21,6 @@
 
 
 class TenantsTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_tenant_list_delete(self):
diff --git a/tempest/api/identity/admin/test_tokens.py b/tempest/api/identity/admin/test_tokens.py
index bec621c..5323fde 100644
--- a/tempest/api/identity/admin/test_tokens.py
+++ b/tempest/api/identity/admin/test_tokens.py
@@ -19,7 +19,6 @@
 
 
 class TokensTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_create_get_delete_token(self):
diff --git a/tempest/api/identity/admin/test_users.py b/tempest/api/identity/admin/test_users.py
index 25312e8..9159468 100644
--- a/tempest/api/identity/admin/test_users.py
+++ b/tempest/api/identity/admin/test_users.py
@@ -21,7 +21,6 @@
 
 
 class UsersTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/test_users_negative.py b/tempest/api/identity/admin/test_users_negative.py
index 33a2f35..db8c564 100644
--- a/tempest/api/identity/admin/test_users_negative.py
+++ b/tempest/api/identity/admin/test_users_negative.py
@@ -23,7 +23,6 @@
 
 
 class UsersNegativeTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_credentials.py b/tempest/api/identity/admin/v3/test_credentials.py
index 6f2f6d4..f22ceec 100644
--- a/tempest/api/identity/admin/v3/test_credentials.py
+++ b/tempest/api/identity/admin/v3/test_credentials.py
@@ -19,7 +19,6 @@
 
 
 class CredentialsTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_default_project_id.py b/tempest/api/identity/admin/v3/test_default_project_id.py
index bd29cb8..72d323a 100644
--- a/tempest/api/identity/admin/v3/test_default_project_id.py
+++ b/tempest/api/identity/admin/v3/test_default_project_id.py
@@ -18,7 +18,6 @@
 
 
 class TestDefaultProjectId (base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
@@ -74,8 +73,7 @@
                                            domain_name=dom_name)
         auth_provider = auth.KeystoneV3AuthProvider(creds)
         creds = auth_provider.fill_credentials()
-        admin_client = clients.Manager(interface=self._interface,
-                                       credentials=creds)
+        admin_client = clients.Manager(credentials=creds)
 
         # verify the user's token and see that it is scoped to the project
         token, auth_data = admin_client.auth_provider.get_auth()
diff --git a/tempest/api/identity/admin/v3/test_domains.py b/tempest/api/identity/admin/v3/test_domains.py
index c1bc705..0914674 100644
--- a/tempest/api/identity/admin/v3/test_domains.py
+++ b/tempest/api/identity/admin/v3/test_domains.py
@@ -20,7 +20,6 @@
 
 
 class DomainsTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     def _delete_domain(self, domain_id):
         # It is necessary to disable the domain before deleting,
@@ -62,10 +61,7 @@
         self.assertIsNotNone(domain['id'])
         self.assertEqual(d_name, domain['name'])
         self.assertEqual(d_desc, domain['description'])
-        if self._interface == "json":
-            self.assertEqual(True, domain['enabled'])
-        else:
-            self.assertEqual('true', str(domain['enabled']).lower())
+        self.assertEqual(True, domain['enabled'])
         new_desc = data_utils.rand_name('new-desc-')
         new_name = data_utils.rand_name('new-name-')
 
diff --git a/tempest/api/identity/admin/v3/test_endpoints.py b/tempest/api/identity/admin/v3/test_endpoints.py
index eed0eb5..2283c21 100644
--- a/tempest/api/identity/admin/v3/test_endpoints.py
+++ b/tempest/api/identity/admin/v3/test_endpoints.py
@@ -19,7 +19,6 @@
 
 
 class EndPointsTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_endpoints_negative.py b/tempest/api/identity/admin/v3/test_endpoints_negative.py
index 9da0a57..9846010 100644
--- a/tempest/api/identity/admin/v3/test_endpoints_negative.py
+++ b/tempest/api/identity/admin/v3/test_endpoints_negative.py
@@ -22,7 +22,6 @@
 
 
 class EndpointsNegativeTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_groups.py b/tempest/api/identity/admin/v3/test_groups.py
index d8c7063..6dfddb0 100644
--- a/tempest/api/identity/admin/v3/test_groups.py
+++ b/tempest/api/identity/admin/v3/test_groups.py
@@ -19,7 +19,6 @@
 
 
 class GroupsV3TestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_list_projects.py b/tempest/api/identity/admin/v3/test_list_projects.py
index c0187f9..24b130c 100644
--- a/tempest/api/identity/admin/v3/test_list_projects.py
+++ b/tempest/api/identity/admin/v3/test_list_projects.py
@@ -19,7 +19,6 @@
 
 
 class ListProjectsTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_list_users.py b/tempest/api/identity/admin/v3/test_list_users.py
index e728867..a6c3309 100644
--- a/tempest/api/identity/admin/v3/test_list_users.py
+++ b/tempest/api/identity/admin/v3/test_list_users.py
@@ -19,7 +19,6 @@
 
 
 class UsersV3TestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     def _list_users_with_params(self, params, key, expected, not_expected):
         # Helper method to list users filtered with params and
diff --git a/tempest/api/identity/admin/v3/test_policies.py b/tempest/api/identity/admin/v3/test_policies.py
index 23df13d..0d5dc47 100644
--- a/tempest/api/identity/admin/v3/test_policies.py
+++ b/tempest/api/identity/admin/v3/test_policies.py
@@ -19,7 +19,6 @@
 
 
 class PoliciesTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     def _delete_policy(self, policy_id):
         self.policy_client.delete_policy(policy_id)
diff --git a/tempest/api/identity/admin/v3/test_projects.py b/tempest/api/identity/admin/v3/test_projects.py
index 2cf6458..d879c7a 100644
--- a/tempest/api/identity/admin/v3/test_projects.py
+++ b/tempest/api/identity/admin/v3/test_projects.py
@@ -19,7 +19,6 @@
 
 
 class ProjectsTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_project_create_with_description(self):
diff --git a/tempest/api/identity/admin/v3/test_projects_negative.py b/tempest/api/identity/admin/v3/test_projects_negative.py
index 23a16d1..fc013c5 100644
--- a/tempest/api/identity/admin/v3/test_projects_negative.py
+++ b/tempest/api/identity/admin/v3/test_projects_negative.py
@@ -22,7 +22,6 @@
 
 
 class ProjectsNegativeTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @test.attr(type=['negative', 'gate'])
     def test_list_projects_by_unauthorized_user(self):
diff --git a/tempest/api/identity/admin/v3/test_regions.py b/tempest/api/identity/admin/v3/test_regions.py
index 2ca3538..359c0cf 100644
--- a/tempest/api/identity/admin/v3/test_regions.py
+++ b/tempest/api/identity/admin/v3/test_regions.py
@@ -21,7 +21,6 @@
 
 
 class RegionsTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_roles.py b/tempest/api/identity/admin/v3/test_roles.py
index b8b309d..15ca21e 100644
--- a/tempest/api/identity/admin/v3/test_roles.py
+++ b/tempest/api/identity/admin/v3/test_roles.py
@@ -19,7 +19,6 @@
 
 
 class RolesV3TestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/identity/admin/v3/test_services.py b/tempest/api/identity/admin/v3/test_services.py
index c060094..13e6d66 100644
--- a/tempest/api/identity/admin/v3/test_services.py
+++ b/tempest/api/identity/admin/v3/test_services.py
@@ -21,7 +21,6 @@
 
 
 class ServicesTestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     def _del_service(self, service_id):
         # Used for deleting the services created in this class
diff --git a/tempest/api/identity/admin/v3/test_tokens.py b/tempest/api/identity/admin/v3/test_tokens.py
index de142e0..36be098 100644
--- a/tempest/api/identity/admin/v3/test_tokens.py
+++ b/tempest/api/identity/admin/v3/test_tokens.py
@@ -21,7 +21,6 @@
 
 
 class TokensV3TestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @test.attr(type='smoke')
     def test_tokens(self):
diff --git a/tempest/api/identity/admin/v3/test_trusts.py b/tempest/api/identity/admin/v3/test_trusts.py
index 13c47eb..fd62004 100644
--- a/tempest/api/identity/admin/v3/test_trusts.py
+++ b/tempest/api/identity/admin/v3/test_trusts.py
@@ -16,8 +16,8 @@
 from tempest_lib import exceptions as lib_exc
 
 from tempest.api.identity import base
-from tempest import auth
 from tempest import clients
+from tempest.common import cred_provider
 from tempest.common.utils import data_utils
 from tempest import config
 from tempest import exceptions
@@ -89,13 +89,11 @@
         self.assertIsNotNone(self.trustee_user_id)
 
         # Initialize a new client with the trustor credentials
-        creds = auth.get_credentials(
+        creds = cred_provider.get_credentials(
             username=self.trustor_username,
             password=self.trustor_password,
             tenant_name=self.trustor_project_name)
-        os = clients.Manager(
-            credentials=creds,
-            interface=self._interface)
+        os = clients.Manager(credentials=creds)
         self.trustor_client = os.identity_v3_client
 
     def cleanup_user_and_roles(self):
@@ -187,7 +185,6 @@
 
 
 class TrustsV3TestJSON(BaseTrustsV3Test):
-    _interface = 'json'
 
     def setUp(self):
         super(TrustsV3TestJSON, self).setUp()
diff --git a/tempest/api/identity/admin/v3/test_users.py b/tempest/api/identity/admin/v3/test_users.py
index 4f3ec05..2481d9d 100644
--- a/tempest/api/identity/admin/v3/test_users.py
+++ b/tempest/api/identity/admin/v3/test_users.py
@@ -19,7 +19,6 @@
 
 
 class UsersV3TestJSON(base.BaseIdentityV3AdminTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_user_update(self):
diff --git a/tempest/api/identity/base.py b/tempest/api/identity/base.py
index 90e1a9e..8f07a6a 100644
--- a/tempest/api/identity/base.py
+++ b/tempest/api/identity/base.py
@@ -15,8 +15,8 @@
 
 from tempest_lib import exceptions as lib_exc
 
-from tempest import auth
 from tempest import clients
+from tempest.common import cred_provider
 from tempest.common.utils import data_utils
 from tempest import config
 from tempest.openstack.common import log as logging
@@ -31,8 +31,8 @@
     @classmethod
     def resource_setup(cls):
         super(BaseIdentityAdminTest, cls).resource_setup()
-        cls.os_adm = clients.AdminManager(interface=cls._interface)
-        cls.os = clients.Manager(interface=cls._interface)
+        cls.os_adm = clients.AdminManager()
+        cls.os = clients.Manager()
 
     @classmethod
     def disable_user(cls, user_name):
@@ -149,11 +149,11 @@
 
         @property
         def test_credentials(self):
-            return auth.get_credentials(username=self.test_user,
-                                        user_id=self.user['id'],
-                                        password=self.test_password,
-                                        tenant_name=self.test_tenant,
-                                        tenant_id=self.tenant['id'])
+            return cred_provider.get_credentials(username=self.test_user,
+                                                 user_id=self.user['id'],
+                                                 password=self.test_password,
+                                                 tenant_name=self.test_tenant,
+                                                 tenant_id=self.tenant['id'])
 
         def setup_test_user(self):
             """Set up a test user."""
diff --git a/tempest/api/identity/test_extension.py b/tempest/api/identity/test_extension.py
index e3badfc..bbc4c13 100644
--- a/tempest/api/identity/test_extension.py
+++ b/tempest/api/identity/test_extension.py
@@ -18,7 +18,6 @@
 
 
 class ExtensionTestJSON(base.BaseIdentityV2AdminTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_list_extensions(self):
diff --git a/tempest/api/image/base.py b/tempest/api/image/base.py
index 4d33d37..344742b 100644
--- a/tempest/api/image/base.py
+++ b/tempest/api/image/base.py
@@ -35,7 +35,6 @@
         cls.set_network_resources()
         super(BaseImageTest, cls).resource_setup()
         cls.created_images = []
-        cls._interface = 'json'
         cls.isolated_creds = credentials.get_isolated_credentials(
             cls.__name__, network_resources=cls.network_resources)
         if not CONF.service_available.glance:
diff --git a/tempest/api/image/v2/test_images_member.py b/tempest/api/image/v2/test_images_member.py
index ec1cf14..956829e 100644
--- a/tempest/api/image/v2/test_images_member.py
+++ b/tempest/api/image/v2/test_images_member.py
@@ -15,7 +15,6 @@
 
 
 class ImagesMemberTest(base.BaseV2MemberImageTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_image_share_accept(self):
diff --git a/tempest/api/image/v2/test_images_member_negative.py b/tempest/api/image/v2/test_images_member_negative.py
index 9965286..4402af9 100644
--- a/tempest/api/image/v2/test_images_member_negative.py
+++ b/tempest/api/image/v2/test_images_member_negative.py
@@ -18,7 +18,6 @@
 
 
 class ImagesMemberNegativeTest(base.BaseV2MemberImageTest):
-    _interface = 'json'
 
     @test.attr(type=['negative', 'gate'])
     def test_image_share_invalid_status(self):
diff --git a/tempest/api/messaging/test_claims.py b/tempest/api/messaging/test_claims.py
index 1aab8d2..c9064b0 100644
--- a/tempest/api/messaging/test_claims.py
+++ b/tempest/api/messaging/test_claims.py
@@ -29,7 +29,6 @@
 
 
 class TestClaims(base.BaseMessagingTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/messaging/test_messages.py b/tempest/api/messaging/test_messages.py
index 3c27ac2..dca95fc 100644
--- a/tempest/api/messaging/test_messages.py
+++ b/tempest/api/messaging/test_messages.py
@@ -26,7 +26,6 @@
 
 
 class TestMessages(base.BaseMessagingTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/messaging/test_queues.py b/tempest/api/messaging/test_queues.py
index 04ba8a3..24656bf 100644
--- a/tempest/api/messaging/test_queues.py
+++ b/tempest/api/messaging/test_queues.py
@@ -48,7 +48,6 @@
 
 
 class TestManageQueue(base.BaseMessagingTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/admin/test_agent_management.py b/tempest/api/network/admin/test_agent_management.py
index e7fd016..20948cc 100644
--- a/tempest/api/network/admin/test_agent_management.py
+++ b/tempest/api/network/admin/test_agent_management.py
@@ -18,7 +18,6 @@
 
 
 class AgentManagementTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/admin/test_dhcp_agent_scheduler.py b/tempest/api/network/admin/test_dhcp_agent_scheduler.py
index a89f25c..4eb6b87 100644
--- a/tempest/api/network/admin/test_dhcp_agent_scheduler.py
+++ b/tempest/api/network/admin/test_dhcp_agent_scheduler.py
@@ -17,7 +17,6 @@
 
 
 class DHCPAgentSchedulersTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/admin/test_external_network_extension.py b/tempest/api/network/admin/test_external_network_extension.py
index 06cce48..6e24f8e 100644
--- a/tempest/api/network/admin/test_external_network_extension.py
+++ b/tempest/api/network/admin/test_external_network_extension.py
@@ -15,7 +15,6 @@
 
 
 class ExternalNetworksTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/admin/test_external_networks_negative.py b/tempest/api/network/admin/test_external_networks_negative.py
index 8eb6888..aa8dd9a 100644
--- a/tempest/api/network/admin/test_external_networks_negative.py
+++ b/tempest/api/network/admin/test_external_networks_negative.py
@@ -23,7 +23,6 @@
 
 
 class ExternalNetworksAdminNegativeTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     @test.attr(type=['negative'])
     def test_create_port_with_precreated_floatingip_as_fixed_ip(self):
diff --git a/tempest/api/network/admin/test_floating_ips_admin_actions.py b/tempest/api/network/admin/test_floating_ips_admin_actions.py
index 62ba1b3..ee3b0bb 100644
--- a/tempest/api/network/admin/test_floating_ips_admin_actions.py
+++ b/tempest/api/network/admin/test_floating_ips_admin_actions.py
@@ -22,7 +22,7 @@
 
 
 class FloatingIPAdminTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
+
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/network/admin/test_l3_agent_scheduler.py b/tempest/api/network/admin/test_l3_agent_scheduler.py
index a6de581..05a8e35 100644
--- a/tempest/api/network/admin/test_l3_agent_scheduler.py
+++ b/tempest/api/network/admin/test_l3_agent_scheduler.py
@@ -18,7 +18,6 @@
 
 
 class L3AgentSchedulerTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/admin/test_lbaas_agent_scheduler.py b/tempest/api/network/admin/test_lbaas_agent_scheduler.py
index da1af36..8cfd5c2 100644
--- a/tempest/api/network/admin/test_lbaas_agent_scheduler.py
+++ b/tempest/api/network/admin/test_lbaas_agent_scheduler.py
@@ -18,7 +18,6 @@
 
 
 class LBaaSAgentSchedulerTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/admin/test_load_balancer_admin_actions.py b/tempest/api/network/admin/test_load_balancer_admin_actions.py
index e81616b..2537b28 100644
--- a/tempest/api/network/admin/test_load_balancer_admin_actions.py
+++ b/tempest/api/network/admin/test_load_balancer_admin_actions.py
@@ -19,7 +19,6 @@
 
 
 class LoadBalancerAdminTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     """
     Test admin actions for load balancer.
diff --git a/tempest/api/network/admin/test_quotas.py b/tempest/api/network/admin/test_quotas.py
index f8dfca9..39850f5 100644
--- a/tempest/api/network/admin/test_quotas.py
+++ b/tempest/api/network/admin/test_quotas.py
@@ -20,7 +20,6 @@
 
 
 class QuotasTest(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/base.py b/tempest/api/network/base.py
index 520bec7..4cb1485 100644
--- a/tempest/api/network/base.py
+++ b/tempest/api/network/base.py
@@ -50,7 +50,6 @@
         neutron as True
     """
 
-    _interface = 'json'
     force_tenant_isolation = False
 
     # Default to ipv4.
@@ -421,8 +420,7 @@
 
         try:
             creds = cls.isolated_creds.get_admin_creds()
-            cls.os_adm = clients.Manager(
-                credentials=creds, interface=cls._interface)
+            cls.os_adm = clients.Manager(credentials=creds)
         except NotImplementedError:
             msg = ("Missing Administrative Network API credentials "
                    "in configuration.")
diff --git a/tempest/api/network/test_allowed_address_pair.py b/tempest/api/network/test_allowed_address_pair.py
index 57887ac..a4954af 100644
--- a/tempest/api/network/test_allowed_address_pair.py
+++ b/tempest/api/network/test_allowed_address_pair.py
@@ -23,7 +23,6 @@
 
 
 class AllowedAddressPairTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the Neutron Allowed Address Pair API extension using the Tempest
diff --git a/tempest/api/network/test_extensions.py b/tempest/api/network/test_extensions.py
index 54c3cb9..2b4ccaf 100644
--- a/tempest/api/network/test_extensions.py
+++ b/tempest/api/network/test_extensions.py
@@ -19,7 +19,6 @@
 
 
 class ExtensionsTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/test_extra_dhcp_options.py b/tempest/api/network/test_extra_dhcp_options.py
index bd70323..1faac58 100644
--- a/tempest/api/network/test_extra_dhcp_options.py
+++ b/tempest/api/network/test_extra_dhcp_options.py
@@ -19,7 +19,6 @@
 
 
 class ExtraDHCPOptionsTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations with the Extra DHCP Options Neutron API
diff --git a/tempest/api/network/test_floating_ips.py b/tempest/api/network/test_floating_ips.py
index 1151c5d..43b296c 100644
--- a/tempest/api/network/test_floating_ips.py
+++ b/tempest/api/network/test_floating_ips.py
@@ -24,7 +24,6 @@
 
 
 class FloatingIPTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Quantum API using the REST client for
diff --git a/tempest/api/network/test_floating_ips_negative.py b/tempest/api/network/test_floating_ips_negative.py
index 7e91ba2..81eedd4 100644
--- a/tempest/api/network/test_floating_ips_negative.py
+++ b/tempest/api/network/test_floating_ips_negative.py
@@ -26,7 +26,7 @@
 
 
 class FloatingIPNegativeTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
+
     """
     Test the following negative  operations for floating ips:
 
diff --git a/tempest/api/network/test_fwaas_extensions.py b/tempest/api/network/test_fwaas_extensions.py
index b0318c9..280c5bb 100644
--- a/tempest/api/network/test_fwaas_extensions.py
+++ b/tempest/api/network/test_fwaas_extensions.py
@@ -24,7 +24,6 @@
 
 
 class FWaaSExtensionTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/test_load_balancer.py b/tempest/api/network/test_load_balancer.py
index df76757..107d8cd 100644
--- a/tempest/api/network/test_load_balancer.py
+++ b/tempest/api/network/test_load_balancer.py
@@ -21,7 +21,6 @@
 
 
 class LoadBalancerTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/test_metering_extensions.py b/tempest/api/network/test_metering_extensions.py
index 6ba1ea4..c80d0e9 100644
--- a/tempest/api/network/test_metering_extensions.py
+++ b/tempest/api/network/test_metering_extensions.py
@@ -24,7 +24,6 @@
 
 
 class MeteringTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/test_networks.py b/tempest/api/network/test_networks.py
index a5f9667..0df455e 100644
--- a/tempest/api/network/test_networks.py
+++ b/tempest/api/network/test_networks.py
@@ -27,7 +27,6 @@
 
 
 class NetworksTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
@@ -399,7 +398,6 @@
 
 
 class BulkNetworkOpsTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/network/test_networks_negative.py b/tempest/api/network/test_networks_negative.py
index b694728..09bd9c3 100644
--- a/tempest/api/network/test_networks_negative.py
+++ b/tempest/api/network/test_networks_negative.py
@@ -22,7 +22,6 @@
 
 
 class NetworksNegativeTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     @test.attr(type=['negative', 'smoke'])
     def test_show_non_existent_network(self):
diff --git a/tempest/api/network/test_ports.py b/tempest/api/network/test_ports.py
index bf85e90..2460092 100644
--- a/tempest/api/network/test_ports.py
+++ b/tempest/api/network/test_ports.py
@@ -27,7 +27,6 @@
 
 
 class PortsTestJSON(sec_base.BaseSecGroupTest):
-    _interface = 'json'
 
     """
     Test the following operations for ports:
@@ -300,7 +299,6 @@
 
 
 class PortsAdminExtendedAttrsTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/test_routers.py b/tempest/api/network/test_routers.py
index 210a8af..b0ee00d 100644
--- a/tempest/api/network/test_routers.py
+++ b/tempest/api/network/test_routers.py
@@ -25,7 +25,6 @@
 
 
 class RoutersTest(base.BaseRouterTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/test_routers_negative.py b/tempest/api/network/test_routers_negative.py
index 32dcf74..655fa58 100644
--- a/tempest/api/network/test_routers_negative.py
+++ b/tempest/api/network/test_routers_negative.py
@@ -26,7 +26,6 @@
 
 
 class RoutersNegativeTest(base.BaseRouterTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/test_security_groups.py b/tempest/api/network/test_security_groups.py
index 415dedd..3d26b48 100644
--- a/tempest/api/network/test_security_groups.py
+++ b/tempest/api/network/test_security_groups.py
@@ -24,7 +24,7 @@
 
 
 class SecGroupTest(base.BaseSecGroupTest):
-    _interface = 'json'
+
     _tenant_network_cidr = CONF.network.tenant_network_cidr
 
     @classmethod
diff --git a/tempest/api/network/test_security_groups_negative.py b/tempest/api/network/test_security_groups_negative.py
index 0398c66..47b218c 100644
--- a/tempest/api/network/test_security_groups_negative.py
+++ b/tempest/api/network/test_security_groups_negative.py
@@ -26,7 +26,7 @@
 
 
 class NegativeSecGroupTest(base.BaseSecGroupTest):
-    _interface = 'json'
+
     _tenant_network_cidr = CONF.network.tenant_network_cidr
 
     @classmethod
diff --git a/tempest/api/network/test_service_type_management.py b/tempest/api/network/test_service_type_management.py
index 0492fe3..e620ae6 100644
--- a/tempest/api/network/test_service_type_management.py
+++ b/tempest/api/network/test_service_type_management.py
@@ -17,7 +17,6 @@
 
 
 class ServiceTypeManagementTestJSON(base.BaseNetworkTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/network/test_vpnaas_extensions.py b/tempest/api/network/test_vpnaas_extensions.py
index 9ff406c..d869b55 100644
--- a/tempest/api/network/test_vpnaas_extensions.py
+++ b/tempest/api/network/test_vpnaas_extensions.py
@@ -24,7 +24,6 @@
 
 
 class VPNaaSTestJSON(base.BaseAdminNetworkTest):
-    _interface = 'json'
 
     """
     Tests the following operations in the Neutron API using the REST client for
diff --git a/tempest/api/orchestration/base.py b/tempest/api/orchestration/base.py
index 2a99630..6873756 100644
--- a/tempest/api/orchestration/base.py
+++ b/tempest/api/orchestration/base.py
@@ -59,7 +59,7 @@
     @classmethod
     def _get_identity_admin_client(cls):
         """Returns an instance of the Identity Admin API client."""
-        manager = clients.AdminManager(interface=cls._interface)
+        manager = clients.AdminManager()
         admin_client = manager.identity_client
         return admin_client
 
diff --git a/tempest/api/telemetry/test_telemetry_alarming_api.py b/tempest/api/telemetry/test_telemetry_alarming_api.py
index 2457438..05aed08 100644
--- a/tempest/api/telemetry/test_telemetry_alarming_api.py
+++ b/tempest/api/telemetry/test_telemetry_alarming_api.py
@@ -18,7 +18,6 @@
 
 
 class TelemetryAlarmingAPITestJSON(base.BaseTelemetryTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/telemetry/test_telemetry_notification_api.py b/tempest/api/telemetry/test_telemetry_notification_api.py
index 4223dfc..048e305 100644
--- a/tempest/api/telemetry/test_telemetry_notification_api.py
+++ b/tempest/api/telemetry/test_telemetry_notification_api.py
@@ -21,7 +21,6 @@
 
 
 class TelemetryNotificationAPITestJSON(base.BaseTelemetryTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_multi_backend.py b/tempest/api/volume/admin/test_multi_backend.py
index 65c4bd3..245161a 100644
--- a/tempest/api/volume/admin/test_multi_backend.py
+++ b/tempest/api/volume/admin/test_multi_backend.py
@@ -22,7 +22,6 @@
 
 
 class VolumeMultiBackendV2Test(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_snapshots_actions.py b/tempest/api/volume/admin/test_snapshots_actions.py
index 6c64298..e7d9d7b 100644
--- a/tempest/api/volume/admin/test_snapshots_actions.py
+++ b/tempest/api/volume/admin/test_snapshots_actions.py
@@ -19,7 +19,6 @@
 
 
 class SnapshotsActionsV2Test(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_volume_hosts.py b/tempest/api/volume/admin/test_volume_hosts.py
index a214edf..8189aab 100644
--- a/tempest/api/volume/admin/test_volume_hosts.py
+++ b/tempest/api/volume/admin/test_volume_hosts.py
@@ -18,7 +18,6 @@
 
 
 class VolumeHostsAdminV2TestsJSON(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     @test.attr(type='gate')
     def test_list_hosts(self):
diff --git a/tempest/api/volume/admin/test_volume_quotas.py b/tempest/api/volume/admin/test_volume_quotas.py
index 52f2d90..2a30b54 100644
--- a/tempest/api/volume/admin/test_volume_quotas.py
+++ b/tempest/api/volume/admin/test_volume_quotas.py
@@ -23,7 +23,6 @@
 
 
 class BaseVolumeQuotasAdminV2TestJSON(base.BaseVolumeAdminTest):
-    _interface = "json"
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/volume/admin/test_volume_quotas_negative.py b/tempest/api/volume/admin/test_volume_quotas_negative.py
index d5eb05a..f972457 100644
--- a/tempest/api/volume/admin/test_volume_quotas_negative.py
+++ b/tempest/api/volume/admin/test_volume_quotas_negative.py
@@ -20,7 +20,6 @@
 
 
 class BaseVolumeQuotasNegativeV2TestJSON(base.BaseVolumeAdminTest):
-    _interface = "json"
     force_tenant_isolation = True
 
     @classmethod
diff --git a/tempest/api/volume/admin/test_volume_services.py b/tempest/api/volume/admin/test_volume_services.py
index 46db70f..3bab185 100644
--- a/tempest/api/volume/admin/test_volume_services.py
+++ b/tempest/api/volume/admin/test_volume_services.py
@@ -22,7 +22,6 @@
     Tests Volume Services API.
     volume service list requires admin privileges.
     """
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_volume_types.py b/tempest/api/volume/admin/test_volume_types.py
index 58f1551..f2c1dda 100644
--- a/tempest/api/volume/admin/test_volume_types.py
+++ b/tempest/api/volume/admin/test_volume_types.py
@@ -22,7 +22,6 @@
 
 
 class VolumeTypesV2Test(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     def _delete_volume(self, volume_id):
         self.volumes_client.delete_volume(volume_id)
diff --git a/tempest/api/volume/admin/test_volume_types_extra_specs.py b/tempest/api/volume/admin/test_volume_types_extra_specs.py
index 460a6c3..1ce1402 100644
--- a/tempest/api/volume/admin/test_volume_types_extra_specs.py
+++ b/tempest/api/volume/admin/test_volume_types_extra_specs.py
@@ -19,7 +19,6 @@
 
 
 class VolumeTypesExtraSpecsV2Test(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_volume_types_extra_specs_negative.py b/tempest/api/volume/admin/test_volume_types_extra_specs_negative.py
index 2e2cfd2..2f3b382 100644
--- a/tempest/api/volume/admin/test_volume_types_extra_specs_negative.py
+++ b/tempest/api/volume/admin/test_volume_types_extra_specs_negative.py
@@ -24,7 +24,6 @@
 
 
 class ExtraSpecsNegativeV2Test(base.BaseVolumeAdminTest):
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_volume_types_negative.py b/tempest/api/volume/admin/test_volume_types_negative.py
index 18d54fa..77ca34c 100644
--- a/tempest/api/volume/admin/test_volume_types_negative.py
+++ b/tempest/api/volume/admin/test_volume_types_negative.py
@@ -23,7 +23,6 @@
 
 
 class VolumeTypesNegativeV2Test(base.BaseVolumeAdminTest):
-    _interface = 'json'
 
     @test.attr(type='gate')
     def test_create_with_nonexistent_volume_type(self):
diff --git a/tempest/api/volume/admin/test_volumes_actions.py b/tempest/api/volume/admin/test_volumes_actions.py
index 4feba73..439dd35 100644
--- a/tempest/api/volume/admin/test_volumes_actions.py
+++ b/tempest/api/volume/admin/test_volumes_actions.py
@@ -19,7 +19,6 @@
 
 
 class VolumesActionsV2Test(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/admin/test_volumes_backup.py b/tempest/api/volume/admin/test_volumes_backup.py
index 0739480..d572893 100644
--- a/tempest/api/volume/admin/test_volumes_backup.py
+++ b/tempest/api/volume/admin/test_volumes_backup.py
@@ -24,7 +24,6 @@
 
 
 class VolumesBackupsV2Test(base.BaseVolumeAdminTest):
-    _interface = "json"
 
     @classmethod
     def resource_setup(cls):
diff --git a/tempest/api/volume/base.py b/tempest/api/volume/base.py
index a1858de..2489b79 100644
--- a/tempest/api/volume/base.py
+++ b/tempest/api/volume/base.py
@@ -31,7 +31,6 @@
     """Base test case class for all Cinder API tests."""
 
     _api_version = 2
-    _interface = 'json'
 
     @classmethod
     def resource_setup(cls):
@@ -155,8 +154,7 @@
 
         try:
             cls.adm_creds = cls.isolated_creds.get_admin_creds()
-            cls.os_adm = clients.Manager(
-                credentials=cls.adm_creds, interface=cls._interface)
+            cls.os_adm = clients.Manager(credentials=cls.adm_creds)
         except NotImplementedError:
             msg = "Missing Volume Admin API credentials in configuration."
             raise cls.skipException(msg)
diff --git a/tempest/api/volume/test_volume_transfers.py b/tempest/api/volume/test_volume_transfers.py
index b2961bd..7451050 100644
--- a/tempest/api/volume/test_volume_transfers.py
+++ b/tempest/api/volume/test_volume_transfers.py
@@ -30,13 +30,11 @@
         super(VolumesV2TransfersTest, cls).resource_setup()
 
         # Add another tenant to test volume-transfer
-        cls.os_alt = clients.Manager(cls.isolated_creds.get_alt_creds(),
-                                     interface=cls._interface)
+        cls.os_alt = clients.Manager(cls.isolated_creds.get_alt_creds())
         # Add admin tenant to cleanup resources
         try:
             creds = cls.isolated_creds.get_admin_creds()
-            cls.os_adm = clients.Manager(
-                credentials=creds, interface=cls._interface)
+            cls.os_adm = clients.Manager(credentials=creds)
         except NotImplementedError:
             msg = "Missing Volume Admin API credentials in configuration."
             raise cls.skipException(msg)
diff --git a/tempest/api/volume/test_volumes_get.py b/tempest/api/volume/test_volumes_get.py
index 6d9c438..2a49210 100644
--- a/tempest/api/volume/test_volumes_get.py
+++ b/tempest/api/volume/test_volumes_get.py
@@ -37,15 +37,6 @@
         self.client.delete_volume(volume_id)
         self.client.wait_for_resource_deletion(volume_id)
 
-    def _is_true(self, val):
-        # NOTE(jdg): Temporary conversion method to get cinder patch
-        # merged.  Then we'll make this strict again and
-        # specifically check "true" or "false"
-        if val in ['true', 'True', True]:
-            return True
-        else:
-            return False
-
     def _volume_create_get_update_delete(self, **kwargs):
         # Create a volume, Get it's details and Delete the volume
         volume = {}
@@ -79,13 +70,10 @@
                         'The fetched Volume metadata misses data '
                         'from the created Volume')
 
-        # NOTE(jdg): Revert back to strict true/false checking
-        # after fix for bug #1227837 merges
-        boot_flag = self._is_true(fetched_volume['bootable'])
         if 'imageRef' in kwargs:
-            self.assertEqual(boot_flag, True)
+            self.assertEqual('true', fetched_volume['bootable'])
         if 'imageRef' not in kwargs:
-            self.assertEqual(boot_flag, False)
+            self.assertEqual('false', fetched_volume['bootable'])
 
         # Update Volume
         # Test volume update when display_name is same with original value
@@ -125,13 +113,10 @@
                   self.descrip_field: volume[self.descrip_field]}
         self.client.update_volume(new_volume['id'], **params)
 
-        # NOTE(jdg): Revert back to strict true/false checking
-        # after fix for bug #1227837 merges
-        boot_flag = self._is_true(updated_volume['bootable'])
         if 'imageRef' in kwargs:
-            self.assertEqual(boot_flag, True)
+            self.assertEqual('true', updated_volume['bootable'])
         if 'imageRef' not in kwargs:
-            self.assertEqual(boot_flag, False)
+            self.assertEqual('false', updated_volume['bootable'])
 
     @test.attr(type='smoke')
     def test_volume_create_get_update_delete(self):
diff --git a/tempest/auth.py b/tempest/auth.py
index 5820893..7e1928f 100644
--- a/tempest/auth.py
+++ b/tempest/auth.py
@@ -38,34 +38,21 @@
     Provide authentication
     """
 
-    def __init__(self, credentials, interface=None):
+    def __init__(self, credentials):
         """
         :param credentials: credentials for authentication
-        :param interface: 'json' or 'xml'. Applicable for tempest client only
-            (deprecated: only json now supported)
         """
-        credentials = self._convert_credentials(credentials)
         if self.check_credentials(credentials):
             self.credentials = credentials
         else:
             raise TypeError("Invalid credentials")
-        self.interface = 'json'
         self.cache = None
         self.alt_auth_data = None
         self.alt_part = None
 
-    def _convert_credentials(self, credentials):
-        # Support dict credentials for backwards compatibility
-        if isinstance(credentials, dict):
-            return get_credentials(**credentials)
-        else:
-            return credentials
-
     def __str__(self):
-        return "Creds :{creds}, interface: {interface}, " \
-               "cached auth data: {cache}".format(
-                   creds=self.credentials, interface=self.interface,
-                   cache=self.cache)
+        return "Creds :{creds}, cached auth data: {cache}".format(
+            creds=self.credentials, cache=self.cache)
 
     @abc.abstractmethod
     def _decorate_request(self, filters, method, url, headers=None, body=None,
@@ -201,8 +188,8 @@
 
     token_expiry_threshold = datetime.timedelta(seconds=60)
 
-    def __init__(self, credentials, interface=None):
-        super(KeystoneAuthProvider, self).__init__(credentials, interface)
+    def __init__(self, credentials):
+        super(KeystoneAuthProvider, self).__init__(credentials)
         self.auth_client = self._auth_client()
 
     def _decorate_request(self, filters, method, url, headers=None, body=None,
@@ -440,7 +427,11 @@
             datetime.datetime.utcnow()
 
 
-def get_credentials(fill_in=True, **kwargs):
+def is_identity_version_supported(identity_version):
+    return identity_version in IDENTITY_VERSION
+
+
+def get_credentials(fill_in=True, identity_version='v2', **kwargs):
     """
     Builds a credentials object based on the configured auth_version
 
@@ -448,6 +439,8 @@
            details provided by the identity service. When fill_in is not
            specified, credentials are not validated. Validation can be invoked
            by invoking ``is_valid()``
+    :param identity_version (string): identity API version is used to
+           select the matching auth provider and credentials class
     :param kwargs (dict): Dict of credential key/value pairs
 
     Examples:
@@ -458,14 +451,13 @@
         Returns credentials including IDs:
         >>> get_credentials(username='foo', password='bar', fill_in=True)
     """
-    if CONF.identity.auth_version == 'v2':
-        credential_class = KeystoneV2Credentials
-        auth_provider_class = KeystoneV2AuthProvider
-    elif CONF.identity.auth_version == 'v3':
-        credential_class = KeystoneV3Credentials
-        auth_provider_class = KeystoneV3AuthProvider
-    else:
-        raise exceptions.InvalidConfiguration('Unsupported auth version')
+    if not is_identity_version_supported(identity_version):
+        raise exceptions.InvalidIdentityVersion(
+            identity_version=identity_version)
+
+    credential_class, auth_provider_class = IDENTITY_VERSION.get(
+        identity_version)
+
     creds = credential_class(**kwargs)
     # Fill in the credentials fields that were not specified
     if fill_in:
@@ -638,3 +630,7 @@
              self.project_id is not None,
              self.project_name is not None and valid_project_domain])
         return all([self.password is not None, valid_user, valid_project])
+
+
+IDENTITY_VERSION = {'v2': (KeystoneV2Credentials, KeystoneV2AuthProvider),
+                    'v3': (KeystoneV3Credentials, KeystoneV3AuthProvider)}
diff --git a/tempest/cli/simple_read_only/compute/__init__.py b/tempest/cli/simple_read_only/compute/__init__.py
deleted file mode 100644
index e69de29..0000000
--- a/tempest/cli/simple_read_only/compute/__init__.py
+++ /dev/null
diff --git a/tempest/cli/simple_read_only/compute/test_nova.py b/tempest/cli/simple_read_only/compute/test_nova.py
deleted file mode 100644
index aee92fa..0000000
--- a/tempest/cli/simple_read_only/compute/test_nova.py
+++ /dev/null
@@ -1,209 +0,0 @@
-# Copyright 2013 OpenStack Foundation
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-from tempest_lib import decorators
-from tempest_lib import exceptions
-import testtools
-
-from tempest import cli
-from tempest import config
-from tempest.openstack.common import log as logging
-
-CONF = config.CONF
-
-LOG = logging.getLogger(__name__)
-
-
-class SimpleReadOnlyNovaClientTest(cli.ClientTestBase):
-
-    """
-    This is a first pass at a simple read only python-novaclient test. This
-    only exercises client commands that are read only.
-
-    This should test commands:
-    * as a regular user
-    * as a admin user
-    * with and without optional parameters
-    * initially just check return codes, and later test command outputs
-
-    """
-
-    @classmethod
-    def resource_setup(cls):
-        if not CONF.service_available.nova:
-            msg = ("%s skipped as Nova is not available" % cls.__name__)
-            raise cls.skipException(msg)
-        super(SimpleReadOnlyNovaClientTest, cls).resource_setup()
-
-    def nova(self, *args, **kwargs):
-        return self.clients.nova(*args,
-                                 endpoint_type=CONF.compute.endpoint_type,
-                                 **kwargs)
-
-    def test_admin_fake_action(self):
-        self.assertRaises(exceptions.CommandFailed,
-                          self.nova,
-                          'this-does-nova-exist')
-
-    # NOTE(jogo): Commands in order listed in 'nova help'
-
-    # Positional arguments:
-
-    def test_admin_absolute_limites(self):
-        self.nova('absolute-limits')
-        self.nova('absolute-limits', params='--reserved')
-
-    def test_admin_aggregate_list(self):
-        self.nova('aggregate-list')
-
-    def test_admin_availability_zone_list(self):
-        self.assertIn("internal", self.nova('availability-zone-list'))
-
-    def test_admin_cloudpipe_list(self):
-        self.nova('cloudpipe-list')
-
-    def test_admin_credentials(self):
-        self.nova('credentials')
-
-    @testtools.skipIf(CONF.service_available.neutron,
-                      "Neutron does not provide this feature")
-    def test_admin_dns_domains(self):
-        self.nova('dns-domains')
-
-    @decorators.skip_because(bug="1157349")
-    def test_admin_dns_list(self):
-        self.nova('dns-list')
-
-    def test_admin_endpoints(self):
-        self.nova('endpoints')
-
-    def test_admin_flavor_acces_list(self):
-        self.assertRaises(exceptions.CommandFailed,
-                          self.nova,
-                          'flavor-access-list')
-        # Failed to get access list for public flavor type
-        self.assertRaises(exceptions.CommandFailed,
-                          self.nova,
-                          'flavor-access-list',
-                          params='--flavor m1.tiny')
-
-    def test_admin_flavor_list(self):
-        self.assertIn("Memory_MB", self.nova('flavor-list'))
-
-    def test_admin_floating_ip_bulk_list(self):
-        self.nova('floating-ip-bulk-list')
-
-    def test_admin_floating_ip_list(self):
-        self.nova('floating-ip-list')
-
-    def test_admin_floating_ip_pool_list(self):
-        self.nova('floating-ip-pool-list')
-
-    def test_admin_host_list(self):
-        self.nova('host-list')
-
-    def test_admin_hypervisor_list(self):
-        self.nova('hypervisor-list')
-
-    def test_admin_image_list(self):
-        self.nova('image-list')
-
-    @decorators.skip_because(bug="1157349")
-    def test_admin_interface_list(self):
-        self.nova('interface-list')
-
-    def test_admin_keypair_list(self):
-        self.nova('keypair-list')
-
-    def test_admin_list(self):
-        self.nova('list')
-        self.nova('list', params='--all-tenants 1')
-        self.nova('list', params='--all-tenants 0')
-        self.assertRaises(exceptions.CommandFailed,
-                          self.nova,
-                          'list',
-                          params='--all-tenants bad')
-
-    def test_admin_network_list(self):
-        self.nova('network-list')
-
-    def test_admin_rate_limits(self):
-        self.nova('rate-limits')
-
-    def test_admin_secgroup_list(self):
-        self.nova('secgroup-list')
-
-    @decorators.skip_because(bug="1157349")
-    def test_admin_secgroup_list_rules(self):
-        self.nova('secgroup-list-rules')
-
-    @cli.min_client_version(client='nova', version='2.18')
-    def test_admin_server_group_list(self):
-        self.nova('server-group-list')
-
-    def test_admin_servce_list(self):
-        self.nova('service-list')
-
-    def test_admin_usage(self):
-        self.nova('usage')
-
-    def test_admin_usage_list(self):
-        self.nova('usage-list')
-
-    @testtools.skipIf(not CONF.service_available.cinder,
-                      "Skipped as Cinder is not available")
-    def test_admin_volume_list(self):
-        self.nova('volume-list')
-
-    @testtools.skipIf(not CONF.service_available.cinder,
-                      "Skipped as Cinder is not available")
-    def test_admin_volume_snapshot_list(self):
-        self.nova('volume-snapshot-list')
-
-    @testtools.skipIf(not CONF.service_available.cinder,
-                      "Skipped as Cinder is not available")
-    def test_admin_volume_type_list(self):
-        self.nova('volume-type-list')
-
-    def test_admin_help(self):
-        self.nova('help')
-
-    def test_admin_list_extensions(self):
-        self.nova('list-extensions')
-
-    def test_admin_net_list(self):
-        self.nova('net-list')
-
-    def test_agent_list(self):
-        self.nova('agent-list')
-        self.nova('agent-list', flags='--debug')
-
-    def test_migration_list(self):
-        self.nova('migration-list')
-        self.nova('migration-list', flags='--debug')
-
-    # Optional arguments:
-
-    def test_admin_version(self):
-        self.nova('', flags='--version')
-
-    def test_admin_debug_list(self):
-        self.nova('list', flags='--debug')
-
-    def test_admin_timeout(self):
-        self.nova('list', flags='--timeout %d' % CONF.cli.timeout)
-
-    def test_admin_timing(self):
-        self.nova('list', flags='--timing')
diff --git a/tempest/clients.py b/tempest/clients.py
index cbc6571..786e05f 100644
--- a/tempest/clients.py
+++ b/tempest/clients.py
@@ -64,7 +64,8 @@
     TenantUsagesClientJSON
 from tempest.services.compute.json.volumes_extensions_client import \
     VolumesExtensionsClientJSON
-from tempest.services.data_processing.v1_1.client import DataProcessingClient
+from tempest.services.data_processing.v1_1.data_processing_client import \
+    DataProcessingClient
 from tempest.services.database.json.flavors_client import \
     DatabaseFlavorsClientJSON
 from tempest.services.database.json.limits_client import \
@@ -155,10 +156,7 @@
     }
     default_params_with_timeout_values.update(default_params)
 
-    def __init__(self, credentials=None, interface='json', service=None):
-        # Set interface and client type first
-        self.interface = interface
-        # super cares for credentials validation
+    def __init__(self, credentials=None, service=None):
         super(Manager, self).__init__(credentials=credentials)
 
         self._set_compute_clients()
@@ -204,6 +202,12 @@
             build_interval=CONF.orchestration.build_interval,
             build_timeout=CONF.orchestration.build_timeout,
             **self.default_params)
+        self.data_processing_client = DataProcessingClient(
+            self.auth_provider,
+            CONF.data_processing.catalog_type,
+            CONF.identity.region,
+            endpoint_type=CONF.data_processing.endpoint_type,
+            **self.default_params_with_timeout_values)
         self.negative_client = negative_rest_client.NegativeRestClient(
             self.auth_provider, service)
 
@@ -214,8 +218,6 @@
                            self.credentials.tenant_name)
         self.ec2api_client = botoclients.APIClientEC2(*ec2_client_args)
         self.s3_client = botoclients.ObjectClientS3(*ec2_client_args)
-        self.data_processing_client = DataProcessingClient(
-            self.auth_provider)
 
     def _set_compute_clients(self):
         params = {
@@ -330,9 +332,12 @@
                                                     **params)
         self.snapshots_v2_client = SnapshotsV2ClientJSON(self.auth_provider,
                                                          **params)
-        self.volumes_client = VolumesClientJSON(self.auth_provider, **params)
-        self.volumes_v2_client = VolumesV2ClientJSON(self.auth_provider,
-                                                     **params)
+        self.volumes_client = VolumesClientJSON(
+            self.auth_provider, default_volume_size=CONF.volume.volume_size,
+            **params)
+        self.volumes_v2_client = VolumesV2ClientJSON(
+            self.auth_provider, default_volume_size=CONF.volume.volume_size,
+            **params)
         self.volume_types_client = VolumeTypesClientJSON(self.auth_provider,
                                                          **params)
         self.volume_services_client = VolumesServicesClientJSON(
@@ -376,9 +381,8 @@
     managed client objects
     """
 
-    def __init__(self, interface='json', service=None):
+    def __init__(self, service=None):
         super(AdminManager, self).__init__(
             credentials=cred_provider.get_configured_credentials(
                 'identity_admin'),
-            interface=interface,
             service=service)
diff --git a/tempest/cmd/cleanup.py b/tempest/cmd/cleanup.py
index 28992b9..c52704a 100755
--- a/tempest/cmd/cleanup.py
+++ b/tempest/cmd/cleanup.py
@@ -54,9 +54,9 @@
 import json
 import sys
 
-from tempest import auth
 from tempest import clients
 from tempest.cmd import cleanup_service
+from tempest.common import cred_provider
 from tempest import config
 from tempest.openstack.common import log as logging
 
@@ -159,7 +159,8 @@
         kwargs = {"username": CONF.identity.admin_username,
                   "password": CONF.identity.admin_password,
                   "tenant_name": tenant['name']}
-        mgr = clients.Manager(credentials=auth.get_credentials(**kwargs))
+        mgr = clients.Manager(credentials=cred_provider.get_credentials(
+            **kwargs))
         kwargs = {'data': tenant_data,
                   'is_dry_run': is_dry_run,
                   'saved_state_json': None,
diff --git a/tempest/cmd/verify_tempest_config.py b/tempest/cmd/verify_tempest_config.py
index 65a3a95..87f5ca6 100755
--- a/tempest/cmd/verify_tempest_config.py
+++ b/tempest/cmd/verify_tempest_config.py
@@ -327,7 +327,7 @@
         CONF_PARSER = moves.configparser.SafeConfigParser()
         CONF_PARSER.optionxform = str
         CONF_PARSER.readfp(conf_file)
-    os = clients.AdminManager(interface='json')
+    os = clients.AdminManager()
     services = check_service_availability(os, update)
     results = {}
     for service in ['nova', 'cinder', 'neutron', 'swift']:
diff --git a/tempest/common/accounts.py b/tempest/common/accounts.py
index 35a1f86..dd8d498 100644
--- a/tempest/common/accounts.py
+++ b/tempest/common/accounts.py
@@ -17,7 +17,6 @@
 
 import yaml
 
-from tempest import auth
 from tempest.common import cred_provider
 from tempest import config
 from tempest import exceptions
@@ -123,7 +122,7 @@
         if self.isolated_creds.get('primary'):
             return self.isolated_creds.get('primary')
         creds = self._get_creds()
-        primary_credential = auth.get_credentials(**creds)
+        primary_credential = cred_provider.get_credentials(**creds)
         self.isolated_creds['primary'] = primary_credential
         return primary_credential
 
@@ -131,7 +130,7 @@
         if self.isolated_creds.get('alt'):
             return self.isolated_creds.get('alt')
         creds = self._get_creds()
-        alt_credential = auth.get_credentials(**creds)
+        alt_credential = cred_provider.get_credentials(**creds)
         self.isolated_creds['alt'] = alt_credential
         return alt_credential
 
@@ -189,7 +188,7 @@
             return self.isolated_creds.get('primary')
         if not self.use_default_creds:
             creds = self.get_creds(0)
-            primary_credential = auth.get_credentials(**creds)
+            primary_credential = cred_provider.get_credentials(**creds)
         else:
             primary_credential = cred_provider.get_configured_credentials(
                 'user')
@@ -201,7 +200,7 @@
             return self.isolated_creds.get('alt')
         if not self.use_default_creds:
             creds = self.get_creds(1)
-            alt_credential = auth.get_credentials(**creds)
+            alt_credential = cred_provider.get_credentials(**creds)
         else:
             alt_credential = cred_provider.get_configured_credentials(
                 'alt_user')
diff --git a/tempest/common/cred_provider.py b/tempest/common/cred_provider.py
index 07fd03f..f40ed7a 100644
--- a/tempest/common/cred_provider.py
+++ b/tempest/common/cred_provider.py
@@ -56,7 +56,7 @@
             params[attr] = getattr(_section, prefix + "_" + attr)
     # Build and validate credentials. We are reading configured credentials,
     # so validate them even if fill_in is False
-    credentials = auth.get_credentials(fill_in=fill_in, **params)
+    credentials = get_credentials(fill_in=fill_in, **params)
     if not fill_in:
         if not credentials.is_valid():
             msg = ("The %s credentials are incorrectly set in the config file."
@@ -66,10 +66,18 @@
     return credentials
 
 
+# Wrapper around auth.get_credentials to use the configured identity version
+# is none is specified
+def get_credentials(fill_in=True, identity_version=None, **kwargs):
+    identity_version = identity_version or CONF.identity.auth_version
+    return auth.get_credentials(fill_in=fill_in,
+                                identity_version=identity_version,
+                                **kwargs)
+
+
 @six.add_metaclass(abc.ABCMeta)
 class CredentialProvider(object):
-    def __init__(self, name, interface='json', password='pass',
-                 network_resources=None):
+    def __init__(self, name, password='pass', network_resources=None):
         self.name = name
 
     @abc.abstractmethod
diff --git a/tempest/common/isolated_creds.py b/tempest/common/isolated_creds.py
index 5c2fa58..1cfb963 100644
--- a/tempest/common/isolated_creds.py
+++ b/tempest/common/isolated_creds.py
@@ -15,7 +15,6 @@
 import netaddr
 from tempest_lib import exceptions as lib_exc
 
-from tempest import auth
 from tempest import clients
 from tempest.common import cred_provider
 from tempest.common.utils import data_utils
@@ -29,15 +28,12 @@
 
 class IsolatedCreds(cred_provider.CredentialProvider):
 
-    def __init__(self, name, interface='json', password='pass',
-                 network_resources=None):
-        super(IsolatedCreds, self).__init__(name, interface, password,
-                                            network_resources)
+    def __init__(self, name, password='pass', network_resources=None):
+        super(IsolatedCreds, self).__init__(name, password, network_resources)
         self.network_resources = network_resources
         self.isolated_creds = {}
         self.isolated_net_resources = {}
         self.ports = []
-        self.interface = interface
         self.password = password
         self.identity_admin_client, self.network_admin_client = (
             self._get_admin_clients())
@@ -49,7 +45,7 @@
             identity
             network
         """
-        os = clients.AdminManager(interface=self.interface)
+        os = clients.AdminManager()
         return os.identity_client, os.network_client
 
     def _create_tenant(self, name, description):
@@ -130,7 +126,7 @@
         return self._get_credentials(user, tenant)
 
     def _get_credentials(self, user, tenant):
-        return auth.get_credentials(
+        return cred_provider.get_credentials(
             username=user['name'], user_id=user['id'],
             tenant_name=tenant['name'], tenant_id=tenant['id'],
             password=self.password)
diff --git a/tempest/exceptions.py b/tempest/exceptions.py
index 81db5d9..09f7016 100644
--- a/tempest/exceptions.py
+++ b/tempest/exceptions.py
@@ -63,6 +63,10 @@
     message = "Invalid service tag"
 
 
+class InvalidIdentityVersion(TempestException):
+    message = "Invalid version %(identity_version) of the identity service"
+
+
 class TimeoutException(TempestException):
     message = "Request timed out"
 
diff --git a/tempest/manager.py b/tempest/manager.py
index 2b00e89..421d2de 100644
--- a/tempest/manager.py
+++ b/tempest/manager.py
@@ -64,5 +64,4 @@
                 'Credentials must be specified')
         auth_provider_class = self.get_auth_provider_class(credentials)
         return auth_provider_class(
-            interface=getattr(self, 'interface', None),
             credentials=credentials)
diff --git a/tempest/services/data_processing/v1_1/client.py b/tempest/services/data_processing/v1_1/data_processing_client.py
similarity index 97%
rename from tempest/services/data_processing/v1_1/client.py
rename to tempest/services/data_processing/v1_1/data_processing_client.py
index 8879373..04cf9a3 100644
--- a/tempest/services/data_processing/v1_1/client.py
+++ b/tempest/services/data_processing/v1_1/data_processing_client.py
@@ -15,20 +15,10 @@
 import json
 
 from tempest.common import service_client
-from tempest import config
-
-CONF = config.CONF
 
 
 class DataProcessingClient(service_client.ServiceClient):
 
-    def __init__(self, auth_provider):
-        super(DataProcessingClient, self).__init__(
-            auth_provider,
-            CONF.data_processing.catalog_type,
-            CONF.identity.region,
-            endpoint_type=CONF.data_processing.endpoint_type)
-
     def _request_and_check_resp(self, request_func, uri, resp_status):
         """Make a request using specified request_func and check response
         status code.
diff --git a/tempest/services/database/json/limits_client.py b/tempest/services/database/json/limits_client.py
index 4daf028..6168bfd 100644
--- a/tempest/services/database/json/limits_client.py
+++ b/tempest/services/database/json/limits_client.py
@@ -15,11 +15,8 @@
 
 import urllib
 
-from tempest import config
 from tempest_lib.common import rest_client
 
-CONF = config.CONF
-
 
 class DatabaseLimitsClientJSON(rest_client.RestClient):
 
diff --git a/tempest/services/identity/v3/json/identity_client.py b/tempest/services/identity/v3/json/identity_client.py
index f3d9d2d..95c52bf 100644
--- a/tempest/services/identity/v3/json/identity_client.py
+++ b/tempest/services/identity/v3/json/identity_client.py
@@ -17,11 +17,8 @@
 import urllib
 
 from tempest.common import service_client
-from tempest import config
 from tempest.services.identity.v3.json import base
 
-CONF = config.CONF
-
 
 class IdentityV3ClientJSON(base.IdentityV3Client):
 
diff --git a/tempest/services/volume/json/volumes_client.py b/tempest/services/volume/json/volumes_client.py
index b906cec..9ef1686 100644
--- a/tempest/services/volume/json/volumes_client.py
+++ b/tempest/services/volume/json/volumes_client.py
@@ -20,11 +20,8 @@
 from tempest_lib import exceptions as lib_exc
 
 from tempest.common import service_client
-from tempest import config
 from tempest import exceptions
 
-CONF = config.CONF
-
 
 class BaseVolumesClientJSON(service_client.ServiceClient):
     """
@@ -33,6 +30,12 @@
 
     create_resp = 200
 
+    def __init__(self, auth_provider, service, region,
+                 default_volume_size=1, **kwargs):
+        super(BaseVolumesClientJSON, self).__init__(
+            auth_provider, service, region, **kwargs)
+        self.default_volume_size = default_volume_size
+
     def get_attachment_from_volume(self, volume):
         """Return the element 'attachment' from input volumes."""
         return volume['attachments'][0]
@@ -79,10 +82,8 @@
         snapshot_id: When specified the volume is created from this snapshot
         imageRef: When specified the volume is created from this image
         """
-        # for bug #1293885:
-        # If no size specified, read volume size from CONF
         if size is None:
-            size = CONF.volume.volume_size
+            size = self.default_volume_size
         post_body = {'size': size}
         post_body.update(kwargs)
         post_body = json.dumps({'volume': post_body})
diff --git a/tempest/stress/driver.py b/tempest/stress/driver.py
index 49fac3d..1c27815 100644
--- a/tempest/stress/driver.py
+++ b/tempest/stress/driver.py
@@ -19,8 +19,8 @@
 
 from six import moves
 
-from tempest import auth
 from tempest import clients
+from tempest.common import cred_provider
 from tempest.common import ssh
 from tempest.common.utils import data_utils
 from tempest import config
@@ -148,9 +148,9 @@
                                             password,
                                             tenant['id'],
                                             "email")
-                creds = auth.get_credentials(username=username,
-                                             password=password,
-                                             tenant_name=tenant_name)
+                creds = cred_provider.get_credentials(username=username,
+                                                      password=password,
+                                                      tenant_name=tenant_name)
                 manager = clients.Manager(credentials=creds)
 
             test_obj = importutils.import_class(test['action'])
diff --git a/tempest/test.py b/tempest/test.py
index 28e1e2c..0c9cbfd 100644
--- a/tempest/test.py
+++ b/tempest/test.py
@@ -359,7 +359,7 @@
                                                    level=None))
 
     @classmethod
-    def get_client_manager(cls, interface=None):
+    def get_client_manager(cls):
         """
         Returns an OpenStack client manager
         """
@@ -373,12 +373,7 @@
             )
 
         creds = cls.isolated_creds.get_primary_creds()
-        params = dict(credentials=creds, service=cls._service)
-        if getattr(cls, '_interface', None):
-            interface = cls._interface
-        if interface:
-            params['interface'] = interface
-        os = clients.Manager(**params)
+        os = clients.Manager(credentials=creds, service=cls._service)
         return os
 
     @classmethod
@@ -394,8 +389,7 @@
         """
         Returns an instance of the Identity Admin API client
         """
-        os = clients.AdminManager(interface=cls._interface,
-                                  service=cls._service)
+        os = clients.AdminManager(service=cls._service)
         admin_client = os.identity_client
         return admin_client
 
@@ -436,8 +430,7 @@
         super(NegativeAutoTest, cls).setUpClass()
         os = cls.get_client_manager()
         cls.client = os.negative_client
-        os_admin = clients.AdminManager(interface=cls._interface,
-                                        service=cls._service)
+        os_admin = clients.AdminManager(service=cls._service)
         cls.admin_client = os_admin.negative_client
 
     @staticmethod
diff --git a/tempest/tests/common/test_service_clients.py b/tempest/tests/common/test_service_clients.py
index 2b31d6b..443b67e 100644
--- a/tempest/tests/common/test_service_clients.py
+++ b/tempest/tests/common/test_service_clients.py
@@ -43,6 +43,7 @@
 from tempest.services.compute.json import tenant_usages_client
 from tempest.services.compute.json import volumes_extensions_client \
     as compute_volumes_extensions_client
+from tempest.services.data_processing.v1_1 import data_processing_client
 from tempest.services.database.json import flavors_client as db_flavor_client
 from tempest.services.database.json import versions_client as db_version_client
 from tempest.services.messaging.json import messaging_client
@@ -117,6 +118,7 @@
             services_client.ServicesClientJSON,
             tenant_usages_client.TenantUsagesClientJSON,
             compute_volumes_extensions_client.VolumesExtensionsClientJSON,
+            data_processing_client.DataProcessingClient,
             db_flavor_client.DatabaseFlavorsClientJSON,
             db_version_client.DatabaseVersionsClientJSON,
             messaging_client.MessagingClientJSON,
diff --git a/tempest/tests/negative/test_negative_auto_test.py b/tempest/tests/negative/test_negative_auto_test.py
index fb1da43..7a127cd 100644
--- a/tempest/tests/negative/test_negative_auto_test.py
+++ b/tempest/tests/negative/test_negative_auto_test.py
@@ -21,7 +21,6 @@
 
 class TestNegativeAutoTest(base.TestCase):
     # Fake entries
-    _interface = 'json'
     _service = 'compute'
 
     fake_input_desc = {"name": "list-flavors-with-detail",
diff --git a/tempest/tests/test_auth.py b/tempest/tests/test_auth.py
index 785880d..0317ad6 100644
--- a/tempest/tests/test_auth.py
+++ b/tempest/tests/test_auth.py
@@ -30,7 +30,7 @@
 from tempest.tests import fake_identity
 
 
-def fake_get_credentials(fill_in=True, **kwargs):
+def fake_get_credentials(fill_in=True, identity_version='v2', **kwargs):
     return fake_credentials.FakeCredentials()
 
 
@@ -81,11 +81,6 @@
     def test_check_credentials_bad_type(self):
         self.assertFalse(self.auth_provider.check_credentials([]))
 
-    def test_instantiate_with_dict(self):
-        # Dict credentials are only supported for backward compatibility
-        auth_provider = self._auth(credentials={})
-        self.assertIsInstance(auth_provider.credentials, auth.Credentials)
-
     def test_auth_data_property_when_cache_exists(self):
         self.auth_provider.cache = 'foo'
         self.useFixture(mockpatch.PatchObject(self.auth_provider,
diff --git a/tempest/tests/test_credentials.py b/tempest/tests/test_credentials.py
index 3d0e171..7621f6e 100644
--- a/tempest/tests/test_credentials.py
+++ b/tempest/tests/test_credentials.py
@@ -15,8 +15,6 @@
 
 import copy
 
-from oslo.config import cfg
-
 from tempest import auth
 from tempest.common import tempest_fixtures as fixtures
 from tempest import config
@@ -78,6 +76,7 @@
     identity_response = fake_identity._fake_v2_response
     credentials_class = auth.KeystoneV2Credentials
     tokenclient_class = v2_client.TokenClientJSON
+    identity_version = 'v2'
 
     def setUp(self):
         super(KeystoneV2CredentialsTests, self).setUp()
@@ -85,7 +84,9 @@
                        self.identity_response)
 
     def _verify_credentials(self, credentials_class, creds_dict, filled=True):
-        creds = auth.get_credentials(fill_in=filled, **creds_dict)
+        creds = auth.get_credentials(fill_in=filled,
+                                     identity_version=self.identity_version,
+                                     **creds_dict)
         self._check(creds, credentials_class, filled)
 
     def test_get_credentials(self):
@@ -156,15 +157,7 @@
     credentials_class = auth.KeystoneV3Credentials
     identity_response = fake_identity._fake_v3_response
     tokenclient_class = v3_client.V3TokenClientJSON
-
-    def setUp(self):
-        super(KeystoneV3CredentialsTests, self).setUp()
-        # Additional config items reset by cfg fixture after each test
-        cfg.CONF.set_default('auth_version', 'v3', group='identity')
-        # Identity group items
-        for prefix in ['', 'alt_', 'admin_']:
-            cfg.CONF.set_default(prefix + 'domain_name', 'fake_domain_name',
-                                 group='identity')
+    identity_version = 'v3'
 
     def test_is_not_valid(self):
         # NOTE(mtreinish) For a Keystone V3 credential object a project name