The default backend driver configured for Cinder backups is "swift" so it would be useful to set the "backup_swift_url" option in cinder.conf to point at the proper server. By default it points to http://localhost:8080/v1/AUTH_ so it only works for AIO deployments. This is reported against: openstack-packstack-2013.2.1-0.27.dev936.el6.noarch