diff --git a/magnum/drivers/heat/template_def.py b/magnum/drivers/heat/template_def.py
index 397b53c45c..b3b33148aa 100755
--- a/magnum/drivers/heat/template_def.py
+++ b/magnum/drivers/heat/template_def.py
@@ -262,7 +262,7 @@ class BaseTemplateDefinition(TemplateDefinition):
         }
         if CONF.trust.trustee_keystone_region_name:
             kwargs['region_name'] = CONF.trust.trustee_keystone_region_name
-        extra_params['auth_url'] = osc.url_for(**kwargs)
+        extra_params['auth_url'] = osc.url_for(**kwargs).rstrip('/')
 
         return super(BaseTemplateDefinition,
                      self).get_params(context, cluster_template, cluster,