Question

我们正在使用Kafka高级消费者，我们能够成功使用消息，但是zookeeper连接会继续到期并重新建立。

我想知道为什么没有心跳来保持连接活着：

Kafka Consumer Logs
====================
 [localhost-startStop-1-SendThread(10.41.105.23:2181)] [ClientCnxn$SendThread] [line : 1096 ]  -  Client session timed out, have not heard from server in 2666ms for sessionid 0x153175bd3860159, closing socket connection and attempting reconnect
2016-03-08 18:00:06,750 INFO  [localhost-startStop-1-SendThread(10.41.105.23:2181)] [ClientCnxn$SendThread] [line : 975 ]  -  Opening socket connection to server 10.41.105.23/10.41.105.23:2181. Will not attempt to authenticate using SASL (unknown error)
2016-03-08 18:00:06,823 INFO  [localhost-startStop-1-SendThread(10.41.105.23:2181)] [ClientCnxn$SendThread] [line : 852 ]  -  Socket connection established to 10.41.105.23/10.41.105.23:2181, initiating session
2016-03-08 18:00:06,892 INFO  [localhost-startStop-1-SendThread(10.41.105.23:2181)] [ClientCnxn$SendThread] [line : 1235 ]  -  Session establishment complete on server 10.41.105.23/10.41.105.23:2181, sessionid = 0x153175bd3860159, negotiated timeout = 4000


Zookeeper Logs
==================
[2016-03-08 17:44:37,722] INFO Accepted socket connection from /10.10.113.92:51333 (org.apache.zookeeper.server.NIOServerCnxnFactory)
[2016-03-08 17:44:37,742] INFO Client attempting to renew session 0x153175bd3860159 at /10.10.113.92:51333 (org.apache.zookeeper.server.ZooKeeperServer)
[2016-03-08 17:44:37,742] INFO Established session 0x153175bd3860159 with negotiated timeout 4000 for client /10.10.113.92:51333 (org.apache.zookeeper.server.ZooKeeperServer)
[2016-03-08 17:46:56,000] INFO Expiring session 0x153175bd3860151, timeout of 4000ms exceeded (org.apache.zookeeper.server.ZooKeeperServer)
[2016-03-08 17:46:56,001] INFO Processed session termination for sessionid: 0x153175bd3860151 (org.apache.zookeeper.server.PrepRequestProcessor)
[2016-03-08 17:46:56,011] INFO Closed socket connection for client /10.10.114.183:38324 which had sessionid 0x153175bd3860151 (org.apache.zookeeper.server.NIOServerCnxn)

Answer 1

ZooKeeper会话超时通常是由“软故障”引起的，这通常是垃圾收集暂停。打开GC日志记录，查看连接超时时是否发生长GC。另请阅读JVM tuning in Kafka。

Answer 2

[2016-03-08 17：46：56,000] INFO过期会话0x153175bd3860151，     超过4000毫秒的超时时间（org.apache.zookeeper.server.ZooKeeperServer）

什么是Zookeeper的maxSessionTimeout？如果只有4000毫秒（4秒），那么它太小了。

在Hadoop的Cloudera发行版中，ZK的maxSessionTimeout默认为40 （40000ms）。

如ZK配置中所述- https://zookeeper.apache.org/doc/r3.4.5/zookeeperAdmin.html 默认为20 ticks （默认情况下，一个tick是2秒）。

Zookeeper会话一直到期......没有心跳？

2 个答案: