diff --git a/charms_openstack/charm/classes.py b/charms_openstack/charm/classes.py
index 46f1977..a71071a 100644
--- a/charms_openstack/charm/classes.py
+++ b/charms_openstack/charm/classes.py
@@ -175,7 +175,7 @@ class OpenStackCharm(BaseOpenStackCharm,
         actions = {
             'pause': os_utils.pause_unit,
             'resume': os_utils.resume_unit}
-        pause_services = self.services
+        pause_services = self.services[:]
         if self.haproxy_enabled():
             pause_services.append('haproxy')
         actions[action](self.assess_status, services=pause_services)
@@ -188,6 +188,17 @@ class OpenStackCharm(BaseOpenStackCharm,
         """Resume the charms services."""
         self.run_pause_or_resume('resume')
 
+    def series_upgrade_prepare(self):
+        """Prepare to upgrade series"""
+        os_utils.set_unit_upgrading()
+        self.run_pause_or_resume('pause')
+
+    def series_upgrade_complete(self):
+        """Prepare to upgrade series"""
+        os_utils.clear_unit_paused()
+        os_utils.clear_unit_upgrading()
+        self.run_pause_or_resume('resume')
+
 
 class OpenStackAPICharm(OpenStackCharm):
     """The base class for API OS charms -- this just bakes in the default