'Check if there is a backup service available.'

def _is_backup_service_enabled(self, availability_zone, host):

    topic = constants.BACKUP_TOPIC
    ctxt = context.get_admin_context()
    services = objects.ServiceList.get_all_by_topic(ctxt, topic, disabled=False)
    for srv in services:
        if (self._az_matched(srv, availability_zone) and (srv.host == host) and srv.is_up):
            return True
    return False
