diff --git a/manifests/init.pp b/manifests/init.pp
index e3f7e885..d46b2d4a 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -83,7 +83,7 @@
 #  [*admin_role*]
 #   Defaults to undef
 #  [*admin_domain_name*]
-#   Defaults to undef
+#   Defaults to $::os_service_default
 #  [*image_ref*]
 #   Defaults to undef
 #  [*image_ref_alt*]
@@ -279,7 +279,7 @@ class tempest(
   $admin_password                   = undef,
   $admin_project_name               = undef,
   $admin_role                       = undef,
-  $admin_domain_name                = undef,
+  $admin_domain_name                = $::os_service_default,
   # roles fo the users created by tempest
   $tempest_roles                    = $::os_service_default,
   # image information
diff --git a/spec/classes/tempest_init_spec.rb b/spec/classes/tempest_init_spec.rb
index 166a5c4a..61c4e1cc 100644
--- a/spec/classes/tempest_init_spec.rb
+++ b/spec/classes/tempest_init_spec.rb
@@ -195,7 +195,7 @@ describe 'tempest' do
         it { should contain_class('openstacklib::openstackclient') }
 
         it 'configure tempest config' do
-          is_expected.to contain_tempest_config('auth/admin_domain_name').with(:value => nil)
+          is_expected.to contain_tempest_config('auth/admin_domain_name').with(:value => '<SERVICE DEFAULT>')
           is_expected.to contain_tempest_config('auth/admin_password').with_secret( true )
           is_expected.to contain_tempest_config('auth/admin_project_name').with(:value => nil)
           is_expected.to contain_tempest_config('auth/admin_username').with(:value => nil)