'Establish connection to the backup Ceph cluster.'

def _connect_to_rados(self, pool=None):

    client = self.rados.Rados(rados_id=self._ceph_backup_user, conffile=self._ceph_backup_conf)
    try:
        client.connect()
        pool_to_open = utils.convert_str((pool or self._ceph_backup_pool))
        ioctx = client.open_ioctx(pool_to_open)
        return (client, ioctx)
    except self.rados.Error:
        client.shutdown()
        raise
