diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index b0c7826..e17da7a 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -307,14 +307,14 @@
 
 # Administrative Username to use for Nova API requests.
 # (string value)
-#username=admin
+#username=<None>
 
 # Administrative Tenant name to use for Nova API requests.
 # (string value)
-#tenant_name=admin
+#tenant_name=<None>
 
 # API key to use when authenticating as admin. (string value)
-#password=pass
+#password=<None>
 
 
 [compute-feature-enabled]
@@ -451,16 +451,16 @@
 #endpoint_type=publicURL
 
 # Username to use for Nova API requests. (string value)
-#username=demo
+#username=<None>
 
 # Tenant name to use for Nova API requests. (string value)
-#tenant_name=demo
+#tenant_name=<None>
 
 # Role required to administrate keystone. (string value)
 #admin_role=admin
 
 # API key to use when authenticating. (string value)
-#password=pass
+#password=<None>
 
 # Username of alternate user to use for Nova API requests.
 # (string value)
@@ -476,14 +476,14 @@
 
 # Administrative Username to use for Keystone API requests.
 # (string value)
-#admin_username=admin
+#admin_username=<None>
 
 # Administrative Tenant name to use for Keystone API requests.
 # (string value)
-#admin_tenant_name=admin
+#admin_tenant_name=<None>
 
 # API key to use when authenticating as admin. (string value)
-#admin_password=pass
+#admin_password=<None>
 
 
 [identity-feature-enabled]
diff --git a/tempest/config.py b/tempest/config.py
index 0c33233..a0f64d5 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -60,16 +60,16 @@
                         'publicURL', 'adminURL', 'internalURL'],
                help="The endpoint type to use for the identity service."),
     cfg.StrOpt('username',
-               default='demo',
+               default=None,
                help="Username to use for Nova API requests."),
     cfg.StrOpt('tenant_name',
-               default='demo',
+               default=None,
                help="Tenant name to use for Nova API requests."),
     cfg.StrOpt('admin_role',
                default='admin',
                help="Role required to administrate keystone."),
     cfg.StrOpt('password',
-               default='pass',
+               default=None,
                help="API key to use when authenticating.",
                secret=True),
     cfg.StrOpt('alt_username',
@@ -85,15 +85,15 @@
                help="API key to use when authenticating as alternate user.",
                secret=True),
     cfg.StrOpt('admin_username',
-               default='admin',
+               default=None,
                help="Administrative Username to use for "
                     "Keystone API requests."),
     cfg.StrOpt('admin_tenant_name',
-               default='admin',
+               default=None,
                help="Administrative Tenant name to use for Keystone API "
                     "requests."),
     cfg.StrOpt('admin_password',
-               default='pass',
+               default=None,
                help="API key to use when authenticating as admin.",
                secret=True),
 ]
@@ -276,14 +276,14 @@
 
 ComputeAdminGroup = [
     cfg.StrOpt('username',
-               default='admin',
+               default=None,
                help="Administrative Username to use for Nova API requests."),
     cfg.StrOpt('tenant_name',
-               default='admin',
+               default=None,
                help="Administrative Tenant name to use for Nova API "
                     "requests."),
     cfg.StrOpt('password',
-               default='pass',
+               default=None,
                help="API key to use when authenticating as admin.",
                secret=True),
 ]