diff --git a/tempest/api/object_storage/base.py b/tempest/api/object_storage/base.py
index 11273e4..4c49b2a 100644
--- a/tempest/api/object_storage/base.py
+++ b/tempest/api/object_storage/base.py
@@ -71,9 +71,6 @@
     def setup_credentials(cls):
         cls.set_network_resources()
         super(BaseObjectTest, cls).setup_credentials()
-        # credentials may be overwritten by children classes
-        if hasattr(cls, 'os_roles_operator'):
-            cls.os = cls.os_roles_operator
 
     @classmethod
     def setup_clients(cls):
diff --git a/tempest/api/object_storage/test_account_quotas.py b/tempest/api/object_storage/test_account_quotas.py
index 092d369..f46c256 100644
--- a/tempest/api/object_storage/test_account_quotas.py
+++ b/tempest/api/object_storage/test_account_quotas.py
@@ -29,7 +29,6 @@
     @classmethod
     def setup_credentials(cls):
         super(AccountQuotasTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_reselleradmin = cls.os_roles_reseller
 
     @classmethod
diff --git a/tempest/api/object_storage/test_account_quotas_negative.py b/tempest/api/object_storage/test_account_quotas_negative.py
index 60233b4..431bbe9 100644
--- a/tempest/api/object_storage/test_account_quotas_negative.py
+++ b/tempest/api/object_storage/test_account_quotas_negative.py
@@ -29,7 +29,6 @@
     @classmethod
     def setup_credentials(cls):
         super(AccountQuotasNegativeTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_reselleradmin = cls.os_roles_reseller
 
     @classmethod
diff --git a/tempest/api/object_storage/test_account_services.py b/tempest/api/object_storage/test_account_services.py
index 2fb676f..65cebb3 100644
--- a/tempest/api/object_storage/test_account_services.py
+++ b/tempest/api/object_storage/test_account_services.py
@@ -36,7 +36,6 @@
     @classmethod
     def setup_credentials(cls):
         super(AccountTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_operator = cls.os_roles_operator_alt
 
     @classmethod
diff --git a/tempest/api/object_storage/test_account_services_negative.py b/tempest/api/object_storage/test_account_services_negative.py
index e98a4f5..3e664d7 100644
--- a/tempest/api/object_storage/test_account_services_negative.py
+++ b/tempest/api/object_storage/test_account_services_negative.py
@@ -28,7 +28,6 @@
     @classmethod
     def setup_credentials(cls):
         super(AccountNegativeTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_operator = cls.os_roles_operator_alt
 
     @decorators.attr(type=['negative'])
diff --git a/tempest/api/object_storage/test_container_acl_negative.py b/tempest/api/object_storage/test_container_acl_negative.py
index 655626c..e064753 100644
--- a/tempest/api/object_storage/test_container_acl_negative.py
+++ b/tempest/api/object_storage/test_container_acl_negative.py
@@ -29,7 +29,6 @@
     @classmethod
     def setup_credentials(cls):
         super(ObjectACLsNegativeTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_operator = cls.os_roles_operator_alt
 
     @classmethod
diff --git a/tempest/api/object_storage/test_container_sync.py b/tempest/api/object_storage/test_container_sync.py
index 4cb1914..7665b48 100644
--- a/tempest/api/object_storage/test_container_sync.py
+++ b/tempest/api/object_storage/test_container_sync.py
@@ -41,7 +41,6 @@
     @classmethod
     def setup_credentials(cls):
         super(ContainerSyncTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_alt = cls.os_roles_operator_alt
 
     @classmethod
diff --git a/tempest/api/object_storage/test_object_services.py b/tempest/api/object_storage/test_object_services.py
index 556ca2f..d3cdb72 100644
--- a/tempest/api/object_storage/test_object_services.py
+++ b/tempest/api/object_storage/test_object_services.py
@@ -967,7 +967,6 @@
     @classmethod
     def setup_credentials(cls):
         super(PublicObjectTest, cls).setup_credentials()
-        cls.os = cls.os_roles_operator
         cls.os_alt = cls.os_roles_operator_alt
 
     @classmethod