diff --git a/tempest/api/compute/base.py b/tempest/api/compute/base.py
index edeb2fc..8734624 100644
--- a/tempest/api/compute/base.py
+++ b/tempest/api/compute/base.py
@@ -38,6 +38,8 @@
         cls.set_network_resources()
         super(BaseComputeTest, cls).setUpClass()
 
+        # TODO(andreaf) WE should care also for the alt_manager here
+        # but only once client lazy load in the manager is done
         os = cls.get_client_manager()
 
         cls.os = os
@@ -348,23 +350,19 @@
     @classmethod
     def setUpClass(cls):
         super(BaseV2ComputeAdminTest, cls).setUpClass()
-        admin_username = CONF.compute_admin.username
-        admin_password = CONF.compute_admin.password
-        admin_tenant = CONF.compute_admin.tenant_name
-        if not (admin_username and admin_password and admin_tenant):
-            msg = ("Missing Compute Admin API credentials "
-                   "in configuration.")
-            raise cls.skipException(msg)
         if (CONF.compute.allow_tenant_isolation or
             cls.force_tenant_isolation is True):
             creds = cls.isolated_creds.get_admin_creds()
-            admin_username, admin_tenant_name, admin_password = creds
-            cls.os_adm = clients.Manager(username=admin_username,
-                                         password=admin_password,
-                                         tenant_name=admin_tenant_name,
+            cls.os_adm = clients.Manager(credentials=creds,
                                          interface=cls._interface)
         else:
-            cls.os_adm = clients.ComputeAdminManager(interface=cls._interface)
+            try:
+                cls.os_adm = clients.ComputeAdminManager(
+                    interface=cls._interface)
+            except exceptions.InvalidCredentials:
+                msg = ("Missing Compute Admin API credentials "
+                       "in configuration.")
+                raise cls.skipException(msg)
 
 
 class BaseV3ComputeTest(BaseComputeTest):
@@ -378,22 +376,18 @@
     @classmethod
     def setUpClass(cls):
         super(BaseV3ComputeAdminTest, cls).setUpClass()
-        admin_username = CONF.compute_admin.username
-        admin_password = CONF.compute_admin.password
-        admin_tenant = CONF.compute_admin.tenant_name
-        if not (admin_username and admin_password and admin_tenant):
-            msg = ("Missing Compute Admin API credentials "
-                   "in configuration.")
-            raise cls.skipException(msg)
         if CONF.compute.allow_tenant_isolation:
             creds = cls.isolated_creds.get_admin_creds()
-            admin_username, admin_tenant_name, admin_password = creds
-            os_adm = clients.Manager(username=admin_username,
-                                     password=admin_password,
-                                     tenant_name=admin_tenant_name,
+            os_adm = clients.Manager(credentials=creds,
                                      interface=cls._interface)
         else:
-            os_adm = clients.ComputeAdminManager(interface=cls._interface)
+            try:
+                cls.os_adm = clients.ComputeAdminManager(
+                    interface=cls._interface)
+            except exceptions.InvalidCredentials:
+                msg = ("Missing Compute Admin API credentials "
+                       "in configuration.")
+                raise cls.skipException(msg)
 
         cls.os_adm = os_adm
         cls.servers_admin_client = cls.os_adm.servers_v3_client
diff --git a/tempest/api/compute/test_authorization.py b/tempest/api/compute/test_authorization.py
index c87f24e..375ddf8 100644
--- a/tempest/api/compute/test_authorization.py
+++ b/tempest/api/compute/test_authorization.py
@@ -43,10 +43,7 @@
 
         if CONF.compute.allow_tenant_isolation:
             creds = cls.isolated_creds.get_alt_creds()
-            username, tenant_name, password = creds
-            cls.alt_manager = clients.Manager(username=username,
-                                              password=password,
-                                              tenant_name=tenant_name)
+            cls.alt_manager = clients.Manager(credentials=creds)
         else:
             # Use the alt_XXX credentials in the config file
             cls.alt_manager = clients.AltManager()
diff --git a/tempest/api/identity/admin/v3/test_trusts.py b/tempest/api/identity/admin/v3/test_trusts.py
index cae20ad..8e3a7d1 100644
--- a/tempest/api/identity/admin/v3/test_trusts.py
+++ b/tempest/api/identity/admin/v3/test_trusts.py
@@ -13,6 +13,7 @@
 import datetime
 import re
 from tempest.api.identity import base
+from tempest import auth
 from tempest import clients
 from tempest.common.utils import data_utils
 from tempest import config
@@ -88,10 +89,13 @@
         self.assertIsNotNone(self.trustee_user_id)
 
         # Initialize a new client with the trustor credentials
-        os = clients.Manager(username=self.trustor_username,
-                             password=self.trustor_password,
-                             tenant_name=self.trustor_project_name,
-                             interface=self._interface)
+        creds = auth.get_credentials(
+            username=self.trustor_username,
+            password=self.trustor_password,
+            tenant_name=self.trustor_project_name)
+        os = clients.Manager(
+            credentials=creds,
+            interface=self._interface)
         self.trustor_client = os.identity_v3_client
 
     def cleanup_user_and_roles(self):
diff --git a/tempest/api/identity/base.py b/tempest/api/identity/base.py
index a5bf248..e4e74c1 100644
--- a/tempest/api/identity/base.py
+++ b/tempest/api/identity/base.py
@@ -14,6 +14,7 @@
 #    under the License.
 
 
+from tempest import auth
 from tempest import clients
 from tempest.common.utils import data_utils
 from tempest import config
@@ -120,6 +121,14 @@
             self.projects = []
             self.v3_roles = []
 
+        @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'])
+
         def setup_test_user(self):
             """Set up a test user."""
             self.setup_test_tenant()
diff --git a/tempest/api/image/base.py b/tempest/api/image/base.py
index e439238..31ffd14 100644
--- a/tempest/api/image/base.py
+++ b/tempest/api/image/base.py
@@ -42,11 +42,7 @@
             skip_msg = ("%s skipped as glance is not available" % cls.__name__)
             raise cls.skipException(skip_msg)
         if CONF.compute.allow_tenant_isolation:
-            creds = cls.isolated_creds.get_primary_creds()
-            username, tenant_name, password = creds
-            cls.os = clients.Manager(username=username,
-                                     password=password,
-                                     tenant_name=tenant_name)
+            cls.os = clients.Manager(cls.isolated_creds.get_primary_creds())
         else:
             cls.os = clients.Manager()
 
@@ -96,11 +92,7 @@
     def setUpClass(cls):
         super(BaseV1ImageMembersTest, cls).setUpClass()
         if CONF.compute.allow_tenant_isolation:
-            creds = cls.isolated_creds.get_alt_creds()
-            username, tenant_name, password = creds
-            cls.os_alt = clients.Manager(username=username,
-                                         password=password,
-                                         tenant_name=tenant_name)
+            cls.os_alt = clients.Manager(cls.isolated_creds.get_alt_creds())
             cls.alt_tenant_id = cls.isolated_creds.get_alt_tenant()['id']
         else:
             cls.os_alt = clients.AltManager()
@@ -139,12 +131,8 @@
         super(BaseV2MemberImageTest, cls).setUpClass()
         if CONF.compute.allow_tenant_isolation:
             creds = cls.isolated_creds.get_alt_creds()
-            username, tenant_name, password = creds
-            cls.os_alt = clients.Manager(username=username,
-                                         password=password,
-                                         tenant_name=tenant_name,
-                                         interface=cls._interface)
-            cls.alt_tenant_id = cls.isolated_creds.get_alt_tenant()['id']
+            cls.os_alt = clients.Manager(creds)
+            cls.alt_tenant_id = cls.isolated_creds.get_alt_creds().tenant_id
         else:
             cls.os_alt = clients.AltManager()
             alt_tenant_name = cls.os_alt.credentials['tenant_name']
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 bc7f1d6..16238ce 100644
--- a/tempest/api/network/admin/test_load_balancer_admin_actions.py
+++ b/tempest/api/network/admin/test_load_balancer_admin_actions.py
@@ -38,9 +38,9 @@
         cls.force_tenant_isolation = True
         manager = cls.get_client_manager()
         cls.client = manager.network_client
-        username, tenant_name, passwd = cls.isolated_creds.get_primary_creds()
+        primary_creds = cls.isolated_creds.get_primary_creds()
         cls.tenant_id = cls.os_adm.identity_client.get_tenant_by_name(
-            tenant_name)['id']
+            primary_creds.tenant_name)['id']
         cls.network = cls.create_network()
         cls.subnet = cls.create_subnet(cls.network)
         cls.pool = cls.create_pool(data_utils.rand_name('pool-'),
diff --git a/tempest/api/network/base.py b/tempest/api/network/base.py
index 425d3f2..5ab581b 100644
--- a/tempest/api/network/base.py
+++ b/tempest/api/network/base.py
@@ -352,11 +352,7 @@
             raise cls.skipException(msg)
         if (CONF.compute.allow_tenant_isolation or
             cls.force_tenant_isolation is True):
-            creds = cls.isolated_creds.get_admin_creds()
-            admin_username, admin_tenant_name, admin_password = creds
-            cls.os_adm = clients.Manager(username=admin_username,
-                                         password=admin_password,
-                                         tenant_name=admin_tenant_name,
+            cls.os_adm = clients.Manager(cls.isolated_creds.get_admin_creds(),
                                          interface=cls._interface)
         else:
             cls.os_adm = clients.ComputeAdminManager(interface=cls._interface)
diff --git a/tempest/api/object_storage/base.py b/tempest/api/object_storage/base.py
index 45c895b..6b18182 100644
--- a/tempest/api/object_storage/base.py
+++ b/tempest/api/object_storage/base.py
@@ -38,23 +38,12 @@
             cls.__name__, network_resources=cls.network_resources)
         if CONF.compute.allow_tenant_isolation:
             # Get isolated creds for normal user
-            creds = cls.isolated_creds.get_primary_creds()
-            username, tenant_name, password = creds
-            cls.os = clients.Manager(username=username,
-                                     password=password,
-                                     tenant_name=tenant_name)
+            cls.os = clients.Manager(cls.isolated_creds.get_primary_creds())
             # Get isolated creds for admin user
-            admin_creds = cls.isolated_creds.get_admin_creds()
-            admin_username, admin_tenant_name, admin_password = admin_creds
-            cls.os_admin = clients.Manager(username=admin_username,
-                                           password=admin_password,
-                                           tenant_name=admin_tenant_name)
+            cls.os_admin = clients.Manager(
+                cls.isolated_creds.get_admin_creds())
             # Get isolated creds for alt user
-            alt_creds = cls.isolated_creds.get_alt_creds()
-            alt_username, alt_tenant, alt_password = alt_creds
-            cls.os_alt = clients.Manager(username=alt_username,
-                                         password=alt_password,
-                                         tenant_name=alt_tenant)
+            cls.os_alt = clients.Manager(cls.isolated_creds.get_alt_creds())
             # Add isolated users to operator role so that they can create a
             # container in swift.
             cls._assign_member_role()
@@ -92,8 +81,8 @@
 
     @classmethod
     def _assign_member_role(cls):
-        primary_user = cls.isolated_creds.get_primary_user()
-        alt_user = cls.isolated_creds.get_alt_user()
+        primary_creds = cls.isolated_creds.get_primary_creds()
+        alt_creds = cls.isolated_creds.get_alt_creds()
         swift_role = CONF.object_storage.operator_role
         try:
             resp, roles = cls.os_admin.identity_client.list_roles()
@@ -101,9 +90,9 @@
         except StopIteration:
             msg = "No role named %s found" % swift_role
             raise exceptions.NotFound(msg)
-        for user in [primary_user, alt_user]:
-            cls.os_admin.identity_client.assign_user_role(user['tenantId'],
-                                                          user['id'],
+        for creds in [primary_creds, alt_creds]:
+            cls.os_admin.identity_client.assign_user_role(creds.tenant_id,
+                                                          creds.user_id,
                                                           role['id'])
 
     @classmethod
diff --git a/tempest/api/object_storage/test_account_quotas.py b/tempest/api/object_storage/test_account_quotas.py
index c1f468b..021555c 100644
--- a/tempest/api/object_storage/test_account_quotas.py
+++ b/tempest/api/object_storage/test_account_quotas.py
@@ -35,10 +35,7 @@
 
         cls.data.setup_test_user()
 
-        cls.os_reselleradmin = clients.Manager(
-            cls.data.test_user,
-            cls.data.test_password,
-            cls.data.test_tenant)
+        cls.os_reselleradmin = clients.Manager(cls.data.test_credentials)
 
         # Retrieve the ResellerAdmin role id
         reseller_role_id = None
diff --git a/tempest/api/object_storage/test_account_quotas_negative.py b/tempest/api/object_storage/test_account_quotas_negative.py
index 4677f97..f1355db 100644
--- a/tempest/api/object_storage/test_account_quotas_negative.py
+++ b/tempest/api/object_storage/test_account_quotas_negative.py
@@ -35,10 +35,7 @@
 
         cls.data.setup_test_user()
 
-        cls.os_reselleradmin = clients.Manager(
-            cls.data.test_user,
-            cls.data.test_password,
-            cls.data.test_tenant)
+        cls.os_reselleradmin = clients.Manager(cls.data.test_credentials)
 
         # Retrieve the ResellerAdmin role id
         reseller_role_id = None
diff --git a/tempest/api/object_storage/test_account_services.py b/tempest/api/object_storage/test_account_services.py
index 7fb0604..d615374 100644
--- a/tempest/api/object_storage/test_account_services.py
+++ b/tempest/api/object_storage/test_account_services.py
@@ -67,9 +67,7 @@
         self.data.setup_test_user()
 
         os_test_user = clients.Manager(
-            self.data.test_user,
-            self.data.test_password,
-            self.data.test_tenant)
+            self.data.test_credentials)
 
         # Retrieve the id of an operator role of object storage
         test_role_id = None
diff --git a/tempest/api/object_storage/test_account_services_negative.py b/tempest/api/object_storage/test_account_services_negative.py
index 71eaab5..d5f8649 100644
--- a/tempest/api/object_storage/test_account_services_negative.py
+++ b/tempest/api/object_storage/test_account_services_negative.py
@@ -28,9 +28,7 @@
 
         # create user
         self.data.setup_test_user()
-        test_os = clients.Manager(self.data.test_user,
-                                  self.data.test_password,
-                                  self.data.test_tenant)
+        test_os = clients.Manager(self.data.test_credentials)
         test_auth_provider = test_os.auth_provider
         # Get auth for the test user
         test_auth_provider.auth_data
diff --git a/tempest/api/object_storage/test_container_acl.py b/tempest/api/object_storage/test_container_acl.py
index c865ee1..fc51504 100644
--- a/tempest/api/object_storage/test_container_acl.py
+++ b/tempest/api/object_storage/test_container_acl.py
@@ -24,9 +24,7 @@
     def setUpClass(cls):
         super(ObjectTestACLs, cls).setUpClass()
         cls.data.setup_test_user()
-        test_os = clients.Manager(cls.data.test_user,
-                                  cls.data.test_password,
-                                  cls.data.test_tenant)
+        test_os = clients.Manager(cls.data.test_credentials)
         cls.test_auth_data = test_os.auth_provider.auth_data
 
     @classmethod
diff --git a/tempest/api/object_storage/test_container_acl_negative.py b/tempest/api/object_storage/test_container_acl_negative.py
index 547bf87..ca53876 100644
--- a/tempest/api/object_storage/test_container_acl_negative.py
+++ b/tempest/api/object_storage/test_container_acl_negative.py
@@ -26,9 +26,7 @@
     def setUpClass(cls):
         super(ObjectACLsNegativeTest, cls).setUpClass()
         cls.data.setup_test_user()
-        test_os = clients.Manager(cls.data.test_user,
-                                  cls.data.test_password,
-                                  cls.data.test_tenant)
+        test_os = clients.Manager(cls.data.test_credentials)
         cls.test_auth_data = test_os.auth_provider.auth_data
 
     @classmethod
diff --git a/tempest/api/object_storage/test_crossdomain.py b/tempest/api/object_storage/test_crossdomain.py
index 4f399b4..d1541b9 100644
--- a/tempest/api/object_storage/test_crossdomain.py
+++ b/tempest/api/object_storage/test_crossdomain.py
@@ -29,10 +29,7 @@
         # endpoint and test the healthcheck feature.
         cls.data.setup_test_user()
 
-        cls.os_test_user = clients.Manager(
-            cls.data.test_user,
-            cls.data.test_password,
-            cls.data.test_tenant)
+        cls.os_test_user = clients.Manager(cls.data.test_credentials)
 
         cls.xml_start = '<?xml version="1.0"?>\n' \
                         '<!DOCTYPE cross-domain-policy SYSTEM ' \
diff --git a/tempest/api/volume/base.py b/tempest/api/volume/base.py
index ff616fc..4d11d24 100644
--- a/tempest/api/volume/base.py
+++ b/tempest/api/volume/base.py
@@ -136,11 +136,7 @@
                    "in configuration.")
             raise cls.skipException(msg)
         if CONF.compute.allow_tenant_isolation:
-            creds = cls.isolated_creds.get_admin_creds()
-            admin_username, admin_tenant_name, admin_password = creds
-            cls.os_adm = clients.Manager(username=admin_username,
-                                         password=admin_password,
-                                         tenant_name=admin_tenant_name,
+            cls.os_adm = clients.Manager(cls.isolated_creds.get_admin_creds(),
                                          interface=cls._interface)
         else:
             cls.os_adm = clients.AdminManager(interface=cls._interface)
diff --git a/tempest/api/volume/test_volume_transfers.py b/tempest/api/volume/test_volume_transfers.py
index 55a72c1..1ef93b9 100644
--- a/tempest/api/volume/test_volume_transfers.py
+++ b/tempest/api/volume/test_volume_transfers.py
@@ -32,21 +32,13 @@
 
         # Add another tenant to test volume-transfer
         if CONF.compute.allow_tenant_isolation:
-            creds = cls.isolated_creds.get_alt_creds()
-            username, tenant_name, password = creds
-            cls.os_alt = clients.Manager(username=username,
-                                         password=password,
-                                         tenant_name=tenant_name,
+            cls.os_alt = clients.Manager(cls.isolated_creds.get_alt_creds(),
                                          interface=cls._interface)
             cls.alt_tenant_id = cls.isolated_creds.get_alt_tenant()['id']
-
             # Add admin tenant to cleanup resources
-            adm_creds = cls.isolated_creds.get_admin_creds()
-            admin_username, admin_tenant_name, admin_password = adm_creds
-            cls.os_adm = clients.Manager(username=admin_username,
-                                         password=admin_password,
-                                         tenant_name=admin_tenant_name,
+            cls.os_adm = clients.Manager(cls.isolated_creds.get_admin_creds(),
                                          interface=cls._interface)
+
         else:
             cls.os_alt = clients.AltManager()
             alt_tenant_name = cls.os_alt.credentials['tenant_name']
diff --git a/tempest/clients.py b/tempest/clients.py
index 646a2d9..b9550fd 100644
--- a/tempest/clients.py
+++ b/tempest/clients.py
@@ -16,6 +16,7 @@
 import keystoneclient.exceptions
 import keystoneclient.v2_0.client
 
+from tempest import auth
 from tempest.common.rest_client import NegativeRestClient
 from tempest import config
 from tempest import exceptions
@@ -196,22 +197,12 @@
     Top level manager for OpenStack tempest clients
     """
 
-    def __init__(self, username=None, password=None, tenant_name=None,
-                 interface='json', service=None):
-        """
-        We allow overriding of the credentials used within the various
-        client classes managed by the Manager object. Left as None, the
-        standard username/password/tenant_name is used.
-
-        :param username: Override of the username
-        :param password: Override of the password
-        :param tenant_name: Override of the tenant name
-        """
+    def __init__(self, credentials=None, interface='json', service=None):
+        # Set interface and client type first
         self.interface = interface
         self.client_type = 'tempest'
         # super cares for credentials validation
-        super(Manager, self).__init__(
-            username=username, password=password, tenant_name=tenant_name)
+        super(Manager, self).__init__(credentials=credentials)
 
         if self.interface == 'xml':
             self.certificates_client = CertificatesClientXML(
@@ -368,10 +359,10 @@
             raise exceptions.InvalidConfiguration(msg)
 
         # TODO(andreaf) EC2 client still do their auth, v2 only
-        ec2_client_args = (self.credentials.get('username'),
-                           self.credentials.get('password'),
+        ec2_client_args = (self.credentials.username,
+                           self.credentials.password,
                            CONF.identity.uri,
-                           self.credentials.get('tenant_name'))
+                           self.credentials.tenant_name)
 
         # common clients
         self.account_client = AccountClient(self.auth_provider)
@@ -402,11 +393,10 @@
     """
 
     def __init__(self, interface='json', service=None):
-        super(AltManager, self).__init__(CONF.identity.alt_username,
-                                         CONF.identity.alt_password,
-                                         CONF.identity.alt_tenant_name,
-                                         interface=interface,
-                                         service=service)
+        super(AltManager, self).__init__(
+            credentials=auth.get_default_credentials('alt_user'),
+            interface=interface,
+            service=service)
 
 
 class AdminManager(Manager):
@@ -417,11 +407,10 @@
     """
 
     def __init__(self, interface='json', service=None):
-        super(AdminManager, self).__init__(CONF.identity.admin_username,
-                                           CONF.identity.admin_password,
-                                           CONF.identity.admin_tenant_name,
-                                           interface=interface,
-                                           service=service)
+        super(AdminManager, self).__init__(
+            credentials=auth.get_default_credentials('identity_admin'),
+            interface=interface,
+            service=service)
 
 
 class ComputeAdminManager(Manager):
@@ -433,11 +422,10 @@
 
     def __init__(self, interface='json', service=None):
         base = super(ComputeAdminManager, self)
-        base.__init__(CONF.compute_admin.username,
-                      CONF.compute_admin.password,
-                      CONF.compute_admin.tenant_name,
-                      interface=interface,
-                      service=service)
+        base.__init__(
+            credentials=auth.get_default_credentials('compute_admin'),
+            interface=interface,
+            service=service)
 
 
 class OfficialClientManager(manager.Manager):
@@ -452,47 +440,32 @@
     IRONICCLIENT_VERSION = '1'
     SAHARACLIENT_VERSION = '1.1'
 
-    def __init__(self, username, password, tenant_name):
+    def __init__(self, credentials):
         # FIXME(andreaf) Auth provider for client_type 'official' is
         # not implemented yet, setting to 'tempest' for now.
         self.client_type = 'tempest'
         self.interface = None
         # super cares for credentials validation
-        super(OfficialClientManager, self).__init__(
-            username=username, password=password, tenant_name=tenant_name)
+        super(OfficialClientManager, self).__init__(credentials=credentials)
         self.baremetal_client = self._get_baremetal_client()
-        self.compute_client = self._get_compute_client(username,
-                                                       password,
-                                                       tenant_name)
-        self.identity_client = self._get_identity_client(username,
-                                                         password,
-                                                         tenant_name)
+        self.compute_client = self._get_compute_client(credentials)
+        self.identity_client = self._get_identity_client(credentials)
         self.image_client = self._get_image_client()
         self.network_client = self._get_network_client()
-        self.volume_client = self._get_volume_client(username,
-                                                     password,
-                                                     tenant_name)
+        self.volume_client = self._get_volume_client(credentials)
         self.object_storage_client = self._get_object_storage_client(
-            username,
-            password,
-            tenant_name)
+            credentials)
         self.orchestration_client = self._get_orchestration_client(
-            username,
-            password,
-            tenant_name)
+            credentials)
         self.data_processing_client = self._get_data_processing_client(
-            username,
-            password,
-            tenant_name)
+            credentials)
 
     def _get_roles(self):
-        keystone_admin = self._get_identity_client(
-            CONF.identity.admin_username,
-            CONF.identity.admin_password,
-            CONF.identity.admin_tenant_name)
+        admin_credentials = auth.get_default_credentials('identity_admin')
+        keystone_admin = self._get_identity_client(admin_credentials)
 
-        username = self.credentials['username']
-        tenant_name = self.credentials['tenant_name']
+        username = self.credentials.username
+        tenant_name = self.credentials.tenant_name
         user_id = keystone_admin.users.find(name=username).id
         tenant_id = keystone_admin.tenants.find(name=tenant_name).id
 
@@ -501,20 +474,20 @@
 
         return [r.name for r in roles]
 
-    def _get_compute_client(self, username, password, tenant_name):
+    def _get_compute_client(self, credentials):
         # Novaclient will not execute operations for anyone but the
         # identified user, so a new client needs to be created for
         # each user that operations need to be performed for.
         if not CONF.service_available.nova:
             return None
         import novaclient.client
-        self._validate_credentials(username, password, tenant_name)
 
         auth_url = CONF.identity.uri
         dscv = CONF.identity.disable_ssl_certificate_validation
         region = CONF.identity.region
 
-        client_args = (username, password, tenant_name, auth_url)
+        client_args = (credentials.username, credentials.password,
+                       credentials.tenant_name, auth_url)
 
         # Create our default Nova client to use in testing
         service_type = CONF.compute.catalog_type
@@ -542,7 +515,7 @@
         return glanceclient.Client('1', endpoint=endpoint, token=token,
                                    insecure=dscv)
 
-    def _get_volume_client(self, username, password, tenant_name):
+    def _get_volume_client(self, credentials):
         if not CONF.service_available.cinder:
             return None
         import cinderclient.client
@@ -551,25 +524,23 @@
         endpoint_type = CONF.volume.endpoint_type
         dscv = CONF.identity.disable_ssl_certificate_validation
         return cinderclient.client.Client(self.CINDERCLIENT_VERSION,
-                                          username,
-                                          password,
-                                          tenant_name,
+                                          credentials.username,
+                                          credentials.password,
+                                          credentials.tenant_name,
                                           auth_url,
                                           region_name=region,
                                           endpoint_type=endpoint_type,
                                           insecure=dscv,
                                           http_log_debug=True)
 
-    def _get_object_storage_client(self, username, password, tenant_name):
+    def _get_object_storage_client(self, credentials):
         if not CONF.service_available.swift:
             return None
         import swiftclient
         auth_url = CONF.identity.uri
         # add current tenant to swift operator role group.
-        keystone_admin = self._get_identity_client(
-            CONF.identity.admin_username,
-            CONF.identity.admin_password,
-            CONF.identity.admin_tenant_name)
+        admin_credentials = auth.get_default_credentials('identity_admin')
+        keystone_admin = self._get_identity_client(admin_credentials)
 
         # enable test user to operate swift by adding operator role to him.
         roles = keystone_admin.roles.list()
@@ -586,26 +557,18 @@
 
         endpoint_type = CONF.object_storage.endpoint_type
         os_options = {'endpoint_type': endpoint_type}
-        return swiftclient.Connection(auth_url, username, password,
-                                      tenant_name=tenant_name,
+        return swiftclient.Connection(auth_url, credentials.username,
+                                      credentials.password,
+                                      tenant_name=credentials.tenant_name,
                                       auth_version='2',
                                       os_options=os_options)
 
-    def _get_orchestration_client(self, username=None, password=None,
-                                  tenant_name=None):
+    def _get_orchestration_client(self, credentials):
         if not CONF.service_available.heat:
             return None
         import heatclient.client
-        if not username:
-            username = CONF.identity.admin_username
-        if not password:
-            password = CONF.identity.admin_password
-        if not tenant_name:
-            tenant_name = CONF.identity.tenant_name
 
-        self._validate_credentials(username, password, tenant_name)
-
-        keystone = self._get_identity_client(username, password, tenant_name)
+        keystone = self._get_identity_client(credentials)
         region = CONF.identity.region
         endpoint_type = CONF.orchestration.endpoint_type
         token = keystone.auth_token
@@ -622,22 +585,22 @@
             return heatclient.client.Client(self.HEATCLIENT_VERSION,
                                             endpoint,
                                             token=token,
-                                            username=username,
-                                            password=password)
+                                            username=credentials.username,
+                                            password=credentials.password)
 
-    def _get_identity_client(self, username, password, tenant_name):
+    def _get_identity_client(self, credentials):
         # This identity client is not intended to check the security
         # of the identity service, so use admin credentials by default.
-        self._validate_credentials(username, password, tenant_name)
 
         auth_url = CONF.identity.uri
         dscv = CONF.identity.disable_ssl_certificate_validation
 
-        return keystoneclient.v2_0.client.Client(username=username,
-                                                 password=password,
-                                                 tenant_name=tenant_name,
-                                                 auth_url=auth_url,
-                                                 insecure=dscv)
+        return keystoneclient.v2_0.client.Client(
+            username=credentials.username,
+            password=credentials.password,
+            tenant_name=credentials.tenant_name,
+            auth_url=auth_url,
+            insecure=dscv)
 
     def _get_baremetal_client(self):
         # ironic client is currently intended to by used by admin users
@@ -654,9 +617,9 @@
         service_type = CONF.baremetal.catalog_type
         endpoint_type = CONF.baremetal.endpoint_type
         creds = {
-            'os_username': self.credentials['username'],
-            'os_password': self.credentials['password'],
-            'os_tenant_name': self.credentials['tenant_name']
+            'os_username': self.credentials.username,
+            'os_password': self.credentials.password,
+            'os_tenant_name': self.credentials.tenant_name
         }
 
         try:
@@ -680,41 +643,39 @@
         if not CONF.service_available.neutron:
             return None
         import neutronclient.v2_0.client
-        username = CONF.identity.admin_username
-        password = CONF.identity.admin_password
-        tenant_name = CONF.identity.admin_tenant_name
 
-        self._validate_credentials(username, password, tenant_name)
+        credentials = auth.get_default_credentials('identity_admin')
 
         auth_url = CONF.identity.uri
         dscv = CONF.identity.disable_ssl_certificate_validation
         endpoint_type = CONF.network.endpoint_type
 
-        return neutronclient.v2_0.client.Client(username=username,
-                                                password=password,
-                                                tenant_name=tenant_name,
-                                                endpoint_type=endpoint_type,
-                                                auth_url=auth_url,
-                                                insecure=dscv)
+        return neutronclient.v2_0.client.Client(
+            username=credentials.username,
+            password=credentials.password,
+            tenant_name=credentials.tenant_name,
+            endpoint_type=endpoint_type,
+            auth_url=auth_url,
+            insecure=dscv)
 
-    def _get_data_processing_client(self, username, password, tenant_name):
+    def _get_data_processing_client(self, credentials):
         if not CONF.service_available.sahara:
             # Sahara isn't available
             return None
 
         import saharaclient.client
 
-        self._validate_credentials(username, password, tenant_name)
-
         endpoint_type = CONF.data_processing.endpoint_type
         catalog_type = CONF.data_processing.catalog_type
         auth_url = CONF.identity.uri
 
-        client = saharaclient.client.Client(self.SAHARACLIENT_VERSION,
-                                            username, password,
-                                            project_name=tenant_name,
-                                            endpoint_type=endpoint_type,
-                                            service_type=catalog_type,
-                                            auth_url=auth_url)
+        client = saharaclient.client.Client(
+            self.SAHARACLIENT_VERSION,
+            credentials.username,
+            credentials.password,
+            project_name=credentials.tenant_name,
+            endpoint_type=endpoint_type,
+            service_type=catalog_type,
+            auth_url=auth_url)
 
         return client
diff --git a/tempest/common/isolated_creds.py b/tempest/common/isolated_creds.py
index 9a50c0b..8fe3a17 100644
--- a/tempest/common/isolated_creds.py
+++ b/tempest/common/isolated_creds.py
@@ -14,9 +14,6 @@
 
 import netaddr
 
-import keystoneclient.v2_0.client as keystoneclient
-import neutronclient.v2_0.client as neutronclient
-
 from tempest import auth
 from tempest import clients
 from tempest.common.utils import data_utils
@@ -44,24 +41,6 @@
         self.identity_admin_client, self.network_admin_client = (
             self._get_admin_clients())
 
-    def _get_official_admin_clients(self):
-        username = CONF.identity.admin_username
-        password = CONF.identity.admin_password
-        tenant_name = CONF.identity.admin_tenant_name
-        auth_url = CONF.identity.uri
-        dscv = CONF.identity.disable_ssl_certificate_validation
-        identity_client = keystoneclient.Client(username=username,
-                                                password=password,
-                                                tenant_name=tenant_name,
-                                                auth_url=auth_url,
-                                                insecure=dscv)
-        network_client = neutronclient.Client(username=username,
-                                              password=password,
-                                              tenant_name=tenant_name,
-                                              auth_url=auth_url,
-                                              insecure=dscv)
-        return identity_client, network_client
-
     def _get_admin_clients(self):
         """
         Returns a tuple with instances of the following admin clients (in this
@@ -71,11 +50,11 @@
         """
         if self.tempest_client:
             os = clients.AdminManager(interface=self.interface)
-            admin_clients = (os.identity_client,
-                             os.network_client,)
         else:
-            admin_clients = self._get_official_admin_clients()
-        return admin_clients
+            os = clients.OfficialClientManager(
+                auth.get_default_credentials('identity_admin')
+            )
+        return os.identity_client, os.network_client
 
     def _create_tenant(self, name, description):
         if self.tempest_client:
@@ -388,13 +367,13 @@
         else:
             return credentials
 
-    def get_primary_creds(self, old_style=True):
+    def get_primary_creds(self, old_style=False):
         return self.get_credentials('primary', old_style)
 
-    def get_admin_creds(self, old_style=True):
+    def get_admin_creds(self, old_style=False):
         return self.get_credentials('admin', old_style)
 
-    def get_alt_creds(self, old_style=True):
+    def get_alt_creds(self, old_style=False):
         return self.get_credentials('alt', old_style)
 
     def _clear_isolated_router(self, router_id, router_name):
diff --git a/tempest/manager.py b/tempest/manager.py
index 63235db..fb2842f 100644
--- a/tempest/manager.py
+++ b/tempest/manager.py
@@ -29,7 +29,7 @@
     and a client object for a test case to use in performing actions.
     """
 
-    def __init__(self, username=None, password=None, tenant_name=None):
+    def __init__(self, credentials=None):
         """
         We allow overriding of the credentials used within the various
         client classes managed by the Manager object. Left as None, the
@@ -38,29 +38,18 @@
         :param credentials: Override of the credentials
         """
         self.auth_version = CONF.identity.auth_version
-        # FIXME(andreaf) Change Manager __init__ to accept a credentials dict
-        if username is None or password is None:
-            # Tenant None is a valid use case
-            self.credentials = self.get_default_credentials()
+        if credentials is None:
+            self.credentials = auth.get_default_credentials('user')
         else:
-            self.credentials = dict(username=username, password=password,
-                                    tenant_name=tenant_name)
-        if self.auth_version == 'v3':
-            self.credentials['domain_name'] = 'Default'
+            self.credentials = credentials
+        # Check if passed or default credentials are valid
+        if not self.credentials.is_valid():
+            raise exceptions.InvalidCredentials()
         # Creates an auth provider for the credentials
         self.auth_provider = self.get_auth_provider(self.credentials)
         # FIXME(andreaf) unused
         self.client_attr_names = []
 
-    # we do this everywhere, have it be part of the super class
-    def _validate_credentials(self, username, password, tenant_name):
-        if None in (username, password, tenant_name):
-            msg = ("Missing required credentials. "
-                   "username: %(u)s, password: %(p)s, "
-                   "tenant_name: %(t)s" %
-                   {'u': username, 'p': password, 't': tenant_name})
-            raise exceptions.InvalidConfiguration(msg)
-
     @classmethod
     def get_auth_provider_class(cls, auth_version):
         if auth_version == 'v2':
@@ -68,13 +57,6 @@
         else:
             return auth.KeystoneV3AuthProvider
 
-    def get_default_credentials(self):
-        return dict(
-            username=CONF.identity.username,
-            password=CONF.identity.password,
-            tenant_name=CONF.identity.tenant_name
-        )
-
     def get_auth_provider(self, credentials):
         if credentials is None:
             raise exceptions.InvalidCredentials(
diff --git a/tempest/scenario/manager.py b/tempest/scenario/manager.py
index 1e7ddb1..c745f4e 100644
--- a/tempest/scenario/manager.py
+++ b/tempest/scenario/manager.py
@@ -24,6 +24,7 @@
 from novaclient import exceptions as nova_exceptions
 
 from tempest.api.network import common as net_common
+from tempest import auth
 from tempest import clients
 from tempest.common import isolated_creds
 from tempest.common.utils import data_utils
@@ -65,10 +66,8 @@
             cls.__name__, tempest_client=False,
             network_resources=cls.network_resources)
 
-        username, password, tenant_name = cls.credentials()
-
         cls.manager = clients.OfficialClientManager(
-            username, password, tenant_name)
+            credentials=cls.credentials())
         cls.compute_client = cls.manager.compute_client
         cls.image_client = cls.manager.image_client
         cls.baremetal_client = cls.manager.baremetal_client
@@ -82,27 +81,27 @@
         cls.os_resources = []
 
     @classmethod
-    def _get_credentials(cls, get_creds, prefix):
+    def _get_credentials(cls, get_creds, ctype):
         if CONF.compute.allow_tenant_isolation:
-            username, tenant_name, password = get_creds()
+            creds = get_creds()
         else:
-            username = getattr(CONF.identity, prefix + 'username')
-            password = getattr(CONF.identity, prefix + 'password')
-            tenant_name = getattr(CONF.identity, prefix + 'tenant_name')
-        return username, password, tenant_name
+            creds = auth.get_default_credentials(ctype)
+        return creds
 
     @classmethod
     def credentials(cls):
-        return cls._get_credentials(cls.isolated_creds.get_primary_creds, '')
+        return cls._get_credentials(cls.isolated_creds.get_primary_creds,
+                                    'user')
 
     @classmethod
     def alt_credentials(cls):
-        return cls._get_credentials(cls.isolated_creds.get_alt_creds, 'alt_')
+        return cls._get_credentials(cls.isolated_creds.get_alt_creds,
+                                    'alt_user')
 
     @classmethod
     def admin_credentials(cls):
         return cls._get_credentials(cls.isolated_creds.get_admin_creds,
-                                    'admin_')
+                                    'identity_admin')
 
     @staticmethod
     def cleanup_resource(resource, test_name):
@@ -541,13 +540,7 @@
     @classmethod
     def setUpClass(cls):
         super(NetworkScenarioTest, cls).setUpClass()
-        if CONF.compute.allow_tenant_isolation:
-            cls.tenant_id = cls.isolated_creds.get_primary_tenant().id
-        else:
-            cls.tenant_id = cls.manager._get_identity_client(
-                CONF.identity.username,
-                CONF.identity.password,
-                CONF.identity.tenant_name).tenant_id
+        cls.tenant_id = cls.manager.identity_client.tenant_id
 
     def _create_network(self, tenant_id, namestart='network-smoke-'):
         name = data_utils.rand_name(namestart)
@@ -1053,10 +1046,10 @@
 
     @classmethod
     def credentials(cls):
-        username = CONF.identity.admin_username
-        password = CONF.identity.admin_password
-        tenant_name = CONF.identity.tenant_name
-        return username, password, tenant_name
+        admin_creds = auth.get_default_credentials('identity_admin')
+        creds = auth.get_default_credentials('user')
+        admin_creds.tenant_name = creds.tenant_name
+        return admin_creds
 
     def _load_template(self, base_file, file_name):
         filepath = os.path.join(os.path.dirname(os.path.realpath(base_file)),
diff --git a/tempest/scenario/test_security_groups_basic_ops.py b/tempest/scenario/test_security_groups_basic_ops.py
index c76a117..7670662 100644
--- a/tempest/scenario/test_security_groups_basic_ops.py
+++ b/tempest/scenario/test_security_groups_basic_ops.py
@@ -98,17 +98,15 @@
             access point
         """
 
-        def __init__(self, tenant_id, tenant_user, tenant_pass, tenant_name):
-            self.manager = clients.OfficialClientManager(
-                tenant_user,
-                tenant_pass,
-                tenant_name
-            )
+        def __init__(self, credentials):
+            self.manager = clients.OfficialClientManager(credentials)
+            # Credentials from manager are filled with both names and IDs
+            self.creds = self.manager.credentials
             self.keypair = None
-            self.tenant_id = tenant_id
-            self.tenant_name = tenant_name
-            self.tenant_user = tenant_user
-            self.tenant_pass = tenant_pass
+            self.tenant_id = credentials.tenant_id
+            self.tenant_name = credentials.tenant_name
+            self.tenant_user = credentials.username
+            self.tenant_pass = credentials.password
             self.network = None
             self.subnet = None
             self.router = None
@@ -140,19 +138,17 @@
     @classmethod
     def setUpClass(cls):
         super(TestSecurityGroupsBasicOps, cls).setUpClass()
-        alt_creds = cls.alt_credentials()
-        cls.alt_tenant_id = cls.manager._get_identity_client(
-            *alt_creds
-        ).tenant_id
+        cls.alt_creds = cls.alt_credentials()
+        cls.alt_manager = clients.OfficialClientManager(cls.alt_creds)
+        cls.alt_tenant_id = cls.alt_manager.identity_client.tenant_id
         cls.check_preconditions()
         # TODO(mnewby) Consider looking up entities as needed instead
         # of storing them as collections on the class.
         cls.floating_ips = {}
         cls.tenants = {}
-        cls.primary_tenant = cls.TenantProperties(cls.tenant_id,
-                                                  *cls.credentials())
-        cls.alt_tenant = cls.TenantProperties(cls.alt_tenant_id,
-                                              *alt_creds)
+        creds = cls.credentials()
+        cls.primary_tenant = cls.TenantProperties(creds)
+        cls.alt_tenant = cls.TenantProperties(cls.alt_creds)
         for tenant in [cls.primary_tenant, cls.alt_tenant]:
             cls.tenants[tenant.tenant_id] = tenant
         cls.floating_ip_access = not CONF.network.public_router_id
diff --git a/tempest/scenario/utils.py b/tempest/scenario/utils.py
index 4c7b6d7..e2adb34 100644
--- a/tempest/scenario/utils.py
+++ b/tempest/scenario/utils.py
@@ -21,6 +21,7 @@
 import testscenarios
 import testtools
 
+from tempest import auth
 from tempest import clients
 from tempest.common.utils import misc
 from tempest import config
@@ -39,9 +40,8 @@
         self.non_ssh_image_pattern = \
             CONF.input_scenario.non_ssh_image_regex
         # Setup clients
-        ocm = clients.OfficialClientManager(CONF.identity.username,
-                                            CONF.identity.password,
-                                            CONF.identity.tenant_name)
+        ocm = clients.OfficialClientManager(
+            auth.get_default_credentials('user'))
         self.client = ocm.compute_client
 
     def ssh_user(self, image_id):
@@ -99,9 +99,8 @@
                                             digit=string.digits)
 
     def __init__(self):
-        ocm = clients.OfficialClientManager(CONF.identity.username,
-                                            CONF.identity.password,
-                                            CONF.identity.tenant_name)
+        ocm = clients.OfficialClientManager(
+            auth.get_default_credentials('user', fill_in=False))
         self.client = ocm.compute_client
         self.image_pattern = CONF.input_scenario.image_regex
         self.flavor_pattern = CONF.input_scenario.flavor_regex
diff --git a/tempest/stress/driver.py b/tempest/stress/driver.py
index 517cfd5..642108a 100644
--- a/tempest/stress/driver.py
+++ b/tempest/stress/driver.py
@@ -19,6 +19,7 @@
 
 from six import moves
 
+from tempest import auth
 from tempest import clients
 from tempest.common import ssh
 from tempest.common.utils import data_utils
@@ -147,9 +148,10 @@
                                             password,
                                             tenant['id'],
                                             "email")
-                manager = clients.Manager(username=username,
-                                          password="pass",
-                                          tenant_name=tenant_name)
+                creds = auth.get_credentials(username=username,
+                                             password=password,
+                                             tenant_name=tenant_name)
+                manager = clients.Manager(credentials=creds)
 
             test_obj = importutils.import_class(test['action'])
             test_run = test_obj(manager, max_runs, stop_on_error)
diff --git a/tempest/test.py b/tempest/test.py
index 254fffa..748a98c 100644
--- a/tempest/test.py
+++ b/tempest/test.py
@@ -307,26 +307,18 @@
             cls.__name__, network_resources=cls.network_resources)
 
         force_tenant_isolation = getattr(cls, 'force_tenant_isolation', None)
-        if (CONF.compute.allow_tenant_isolation or
-            force_tenant_isolation):
+        if CONF.compute.allow_tenant_isolation or force_tenant_isolation:
             creds = cls.isolated_creds.get_primary_creds()
-            username, tenant_name, password = creds
             if getattr(cls, '_interface', None):
-                os = clients.Manager(username=username,
-                                     password=password,
-                                     tenant_name=tenant_name,
+                os = clients.Manager(credentials=creds,
                                      interface=cls._interface,
                                      service=cls._service)
             elif interface:
-                os = clients.Manager(username=username,
-                                     password=password,
-                                     tenant_name=tenant_name,
+                os = clients.Manager(credentials=creds,
                                      interface=interface,
                                      service=cls._service)
             else:
-                os = clients.Manager(username=username,
-                                     password=password,
-                                     tenant_name=tenant_name,
+                os = clients.Manager(credentials=creds,
                                      service=cls._service)
         else:
             if getattr(cls, '_interface', None):
diff --git a/tempest/tests/test_tenant_isolation.py b/tempest/tests/test_tenant_isolation.py
index 084b6d2..98a896f 100644
--- a/tempest/tests/test_tenant_isolation.py
+++ b/tempest/tests/test_tenant_isolation.py
@@ -17,6 +17,7 @@
 import neutronclient.v2_0.client as neutronclient
 from oslo.config import cfg
 
+from tempest import clients
 from tempest.common import http
 from tempest.common import isolated_creds
 from tempest import config
@@ -52,6 +53,12 @@
     def test_official_client(self):
         self.useFixture(mockpatch.PatchObject(keystoneclient.Client,
                                               'authenticate'))
+        self.useFixture(mockpatch.PatchObject(clients.OfficialClientManager,
+                                              '_get_image_client'))
+        self.useFixture(mockpatch.PatchObject(clients.OfficialClientManager,
+                                              '_get_object_storage_client'))
+        self.useFixture(mockpatch.PatchObject(clients.OfficialClientManager,
+                                              '_get_orchestration_client'))
         iso_creds = isolated_creds.IsolatedCreds('test class',
                                                  tempest_client=False)
         self.assertTrue(isinstance(iso_creds.identity_admin_client,
@@ -142,7 +149,7 @@
         self.addCleanup(user_mock.stop)
         with patch.object(json_iden_client.IdentityClientJSON,
                           'assign_user_role') as user_mock:
-            admin_creds = iso_creds.get_admin_creds(old_style=False)
+            admin_creds = iso_creds.get_admin_creds()
         user_mock.assert_called_once_with('1234', '1234', '1234')
         self.assertEqual(admin_creds.username, 'fake_admin_user')
         self.assertEqual(admin_creds.tenant_name, 'fake_admin_tenant')
@@ -176,7 +183,7 @@
                           [{'id': '123456', 'name': 'admin'}])))
         with patch.object(json_iden_client.IdentityClientJSON,
                           'assign_user_role'):
-            iso_creds.get_admin_creds(old_style=False)
+            iso_creds.get_admin_creds()
         user_mock = self.patch(
             'tempest.services.identity.json.identity_client.'
             'IdentityClientJSON.delete_user')
@@ -290,7 +297,7 @@
                           [{'id': '123456', 'name': 'admin'}])))
         with patch.object(json_iden_client.IdentityClientJSON,
                           'assign_user_role'):
-            iso_creds.get_admin_creds(old_style=False)
+            iso_creds.get_admin_creds()
         self.patch('tempest.services.identity.json.identity_client.'
                    'IdentityClientJSON.delete_user')
         self.patch('tempest.services.identity.json.identity_client.'
@@ -353,7 +360,7 @@
         router_interface_mock = self.patch(
             'tempest.services.network.json.network_client.NetworkClientJSON.'
             'add_router_interface_with_subnet_id')
-        username, tenant_name, password = iso_creds.get_alt_creds()
+        iso_creds.get_alt_creds()
         router_interface_mock.called_once_with('1234', '1234')
         network = iso_creds.get_alt_network()
         subnet = iso_creds.get_alt_subnet()
@@ -384,7 +391,7 @@
                           [{'id': '123456', 'name': 'admin'}])))
         with patch.object(json_iden_client.IdentityClientJSON,
                           'assign_user_role'):
-            username, tenant_name, password = iso_creds.get_admin_creds()
+            iso_creds.get_admin_creds()
         router_interface_mock.called_once_with('1234', '1234')
         network = iso_creds.get_admin_network()
         subnet = iso_creds.get_admin_subnet()
@@ -419,7 +426,7 @@
                               'delete_router')
         router_mock = router.start()
 
-        username, tenant_name, password = iso_creds.get_primary_creds()
+        iso_creds.get_primary_creds()
         self.assertEqual(net_mock.mock_calls, [])
         self.assertEqual(subnet_mock.mock_calls, [])
         self.assertEqual(router_mock.mock_calls, [])