diff --git a/tempest/api/compute/servers/test_servers_negative.py b/tempest/api/compute/servers/test_servers_negative.py
index 5ac667e..6343ead 100644
--- a/tempest/api/compute/servers/test_servers_negative.py
+++ b/tempest/api/compute/servers/test_servers_negative.py
@@ -45,7 +45,10 @@
     def setUpClass(cls):
         super(ServersNegativeTestJSON, cls).setUpClass()
         cls.client = cls.servers_client
-        cls.alt_os = clients.AltManager()
+        if CONF.compute.allow_tenant_isolation:
+            cls.alt_os = clients.Manager(cls.isolated_creds.get_alt_creds())
+        else:
+            cls.alt_os = clients.AltManager()
         cls.alt_client = cls.alt_os.servers_client
         resp, server = cls.create_test_server(wait_until='ACTIVE')
         cls.server_id = server['id']
diff --git a/tempest/api/compute/v3/servers/test_servers_negative.py b/tempest/api/compute/v3/servers/test_servers_negative.py
index 827c4c4..90deaa9 100644
--- a/tempest/api/compute/v3/servers/test_servers_negative.py
+++ b/tempest/api/compute/v3/servers/test_servers_negative.py
@@ -45,7 +45,10 @@
     def setUpClass(cls):
         super(ServersNegativeV3Test, cls).setUpClass()
         cls.client = cls.servers_client
-        cls.alt_os = clients.AltManager()
+        if CONF.compute.allow_tenant_isolation:
+            cls.alt_os = clients.Manager(cls.isolated_creds.get_alt_creds())
+        else:
+            cls.alt_os = clients.AltManager()
         cls.alt_client = cls.alt_os.servers_v3_client
         resp, server = cls.create_test_server(wait_until='ACTIVE')
         cls.server_id = server['id']