diff --git a/charmhelpers/contrib/openstack/cert_utils.py b/charmhelpers/contrib/openstack/cert_utils.py
index 5c961c589..af6248e3d 100644
--- a/charmhelpers/contrib/openstack/cert_utils.py
+++ b/charmhelpers/contrib/openstack/cert_utils.py
@@ -90,7 +90,7 @@ def add_hostname_cn(self):
         if vip:
             addresses.append(vip)
         self.hostname_entry = {
-            'cn': get_hostname(ip),
+            'cn': get_hostname(ip) or ip,
             'addresses': addresses}
 
     def add_hostname_cn_ip(self, addresses):