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更新时间：2024-07-19 GMT+08:00
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创建大量znode后，ZooKeeper Sever启动失败

问题

创建大量znode后，ZooKeeper集群处于故障状态不能自动恢复，尝试重启失败，ZooKeeper server日志显示如下内容：

follower：

2016-06-23 08:00:18,763 | WARN  | QuorumPeer[myid=26](plain=/10.16.9.138:2181)(secure=disabled) | Exception when following the leader | org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:93)
java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
    at java.net.SocketInputStream.read(SocketInputStream.java:170)
    at java.net.SocketInputStream.read(SocketInputStream.java:141)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
    at java.io.DataInputStream.readInt(DataInputStream.java:387)
    at org.apache.jute.BinaryInputArchive.readInt(BinaryInputArchive.java:63)
    at org.apache.zookeeper.server.quorum.QuorumPacket.deserialize(QuorumPacket.java:83)
    at org.apache.jute.BinaryInputArchive.readRecord(BinaryInputArchive.java:99)
    at org.apache.zookeeper.server.quorum.Learner.readPacket(Learner.java:156)
    at org.apache.zookeeper.server.quorum.Learner.registerWithLeader(Learner.java:276)
    at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:75)
    at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:1094)
2016-06-23 08:00:18,764 | INFO  | QuorumPeer[myid=26](plain=/10.16.9.138:2181)(secure=disabled) | shutdown called | org.apache.zookeeper.server.quorum.Follower.shutdown(Follower.java:198)
java.lang.Exception: shutdown Follower
    at org.apache.zookeeper.server.quorum.Follower.shutdown(Follower.java:198)
    at org.apache.zookeeper.server.quorum.QuorumPeer.stopFollower(QuorumPeer.java:1141)
    at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:1098)

leader：

2016-06-23 07:30:57,481 | WARN  | QuorumPeer[myid=25](plain=/10.16.9.136:2181)(secure=disabled) | Unexpected exception | org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:1108)
java.lang.InterruptedException: Timeout while waiting for epoch to be acked by quorum
    at org.apache.zookeeper.server.quorum.Leader.waitForEpochAck(Leader.java:1221)
    at org.apache.zookeeper.server.quorum.Leader.lead(Leader.java:487)
    at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:1105)
2016-06-23 07:30:57,482 | INFO  | QuorumPeer[myid=25](plain=/10.16.9.136:2181)(secure=disabled) | Shutdown called | org.apache.zookeeper.server.quorum.Leader.shutdown(Leader.java:623)
java.lang.Exception: shutdown Leader! reason: Forcing shutdown
    at org.apache.zookeeper.server.quorum.Leader.shutdown(Leader.java:623)
    at org.apache.zookeeper.server.quorum.QuorumPeer.stopLeader(QuorumPeer.java:1149)
    at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:1110)

回答

创建大量节点后，follower与leader同步时数据量大，在集群数据同步限定时间内不能完成同步过程，导致超时，各个ZooKeeper server启动失败。

参考修改集群服务配置参数章节，进入ZooKeeper服务“全部配置”页面。不断尝试调大ZooKeeper配置文件“zoo.cfg”中的“syncLimit”和“initLimit”两参数值，直到ZooKeeperServer正常。

表1 参数说明

参数

描述

默认值

syncLimit

follower与leader进行同步的时间间隔（时长为ticket时长的倍数）。如果在该时间范围内leader没响应，连接将不能被建立。

15

initLimit

follower连接到leader并与leader同步的时间（时长为ticket时长的倍数）。

15

如果将参数“initLimit”和“syncLimit”的参数值均配置为“300”之后，ZooKeeper server仍然无法恢复，则需确认没有其他应用程序正在kill ZooKeeper。例如，参数值为“300”，ticket时长为2000毫秒，即同步限定时间为300*2000ms=600s。

可能存在以下场景，在ZooKeeper中创建的数据过大，需要大量时间与leader同步，并保存到硬盘。在这个过程中，如果ZooKeeper需要运行很长时间，则需确保没有其他监控应用程序kill ZooKeeper而判断其服务停止。

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