@Override
  public void transitPeerSyncReplicationState(String peerId) throws ReplicationException {
    String newStateNode = getNewSyncReplicationStateNode(peerId);
    try {
      byte[] data = ZKUtil.getData(zookeeper, newStateNode);
      ZKUtil.multiOrSequential(zookeeper,
        Arrays.asList(ZKUtilOp.setData(newStateNode, NONE_STATE_ZNODE_BYTES),
          ZKUtilOp.setData(getSyncReplicationStateNode(peerId), data)),
        false);
    } catch (KeeperException | InterruptedException e) {
      throw new ReplicationException(
        "Error transiting sync replication state for peer with id=" + peerId, e);
    }
  }
The name of the znode that contains a list of all remote slave (i.e. peer) clusters.
hbase-replication/src/main/java/org/apache/hadoop/hbase/replication/ZKReplicationPeerStorage.java