def mark_broker_action_done(action, rid=None, unit=None):
    """Mark action as having been completed.

    @param action: name of action to be performed
    @returns None
    """
    rdata = relation_get(rid, unit) or {}
    broker_rsp = rdata.get(get_broker_rsp_key())
    if not broker_rsp:
        return

    rsp = CephBrokerRsp(broker_rsp)
    unit_name = local_unit().partition('/')[2]
    key = "unit_{}_ceph_broker_action.{}".format(unit_name, action)
    kvstore = kv()
    kvstore.set(key=key, value=rsp.request_id)
    kvstore.flush()
Mark action as having been completed.

    @param action: name of action to be performed
    @returns None