報錯：WARN [WorkerSender[myid=1]:QuorumCnxManager@584] - Cannot open channel to 2 at election address /x.x.x.x:3888

報錯背景：

zookeeper安裝完成之后，啟動之后正常，但是查看log文件zookeeper.log時發現報錯。

報錯現象：

2019-05-22 11:40:38,469 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumPeer$QuorumServer@185] - Resolved hostname: 192.168.52.27 to address: /192.168.52.27
2019-05-22 11:40:38,470 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@595] - Notification: 1 (message format version), 3 (n.leader), 0x1000000b2 (n.zxid), 0x1 (n.round), LOOKING (n.state), 1 (n.sid), 0x6 (n.peerEpoch) LOOKING (my state)
2019-05-22 11:40:38,470 [myid:1] - WARN  [WorkerSender[myid=1]:QuorumCnxManager@584] - Cannot open channel to 2 at election address /192.168.52.27:3888
java.net.ConnectException: 拒絕連接 (Connection refused)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:558)
    at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:534)
    at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:454)
    at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:435)
    at java.lang.Thread.run(Thread.java:748)
2019-05-22 11:40:38,470 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumPeer$QuorumServer@185] - Resolved hostname: 192.168.52.27 to address: /192.168.52.27
2019-05-22 11:40:38,504 [myid:1] - INFO  [/192.168.52.28:3888:QuorumCnxManager$Listener@743] - Received connection request /192.168.52.27:56020
2019-05-22 11:40:38,508 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@595] - Notification: 1 (message format version), 2 (n.leader), 0x1000000b2 (n.zxid), 0x1 (n.round), LOOKING (n.state), 2 (n.sid), 0x6 (n.peerEpoch) LOOKING (my state)
2019-05-22 11:40:38,514 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@595] - Notification: 1 (message format version), 3 (n.leader), 0x1000000b2 (n.zxid), 0x1 (n.round), LOOKING (n.state), 2 (n.sid), 0x6 (n.peerEpoch) LOOKING (my state)

報錯原因：

如果是剛啟動zookeeper報出這個錯誤，然后不再不錯，那就是正常現象。是由於有的節點啟動，而有的節點還沒有啟動，這段時間已經啟動的節點就會去努力尋找沒有啟動的節點，就會報出這樣的錯誤。這是一種正常現象，無需多慮。

如果啟動很長時間之后還在報錯，可以嘗試下面的餓解決方案。

報錯解決：

修改每個節點的zoo.cfg文件中的相對應的server.x=0.0.0.0:2888:3888

修改完成后重啟zookeeper，報錯消失。