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https://issues.apache.org/jira/browse/KAFKA-6839?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16459559#comment-16459559
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Edoardo Comar commented on KAFKA-6839:
--------------------------------------
Java does DNS caching
[https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/java-dg-jvm-ttl.html]
> ZK session retry with cname record
> ----------------------------------
>
> Key: KAFKA-6839
> URL: https://issues.apache.org/jira/browse/KAFKA-6839
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 1.1.0
> Reporter: Tyler Monahan
> Priority: Major
>
> I have a 3 node kafka cluster setup in aws that talks to a 3 node zk cluster
> behind an elb. I am giving the kafka instances a dns cname record that points
> to the aws elb which is another cname record pointing to two A records. When
> the aws elb cname record changes the two A records it is pointing at and
> kafka trys to reconnect to zk after losing a session it uses the old A
> records and not the new ones so the reconnect attempt fails. There appears to
> be some kind of caching instead of using the record that is set in the config
> file.
> This is the error message I am seeing in the broker logs.
> {code:java}
> [2018-04-30 20:09:21,449] INFO Opening socket connection to server
> ip-10-65-68-244.us-west-2.compute.internal/10.65.68.244:2181. Will not
> attempt to authenticate using SASL (unknown error)
> (org.apache.zookeeper.ClientCnxn)
> [2018-04-30 20:09:24,450] WARN Client session timed out, have not heard from
> server in 3962ms for sessionid 0x263094512190001
> (org.apache.zookeeper.ClientCnxn)
> [2018-04-30 20:09:24,451] INFO Client session timed out, have not heard from
> server in 3962ms for sessionid 0x263094512190001, closing socket connection
> and attempting reconnect (org.apache.zookeeper.ClientCnxn)
> [2018-04-30 20:09:26,532] INFO Opening socket connection to server
> ip-10-65-84-102.us-west-2.compute.internal/10.65.84.102:2181. Will not
> attempt to authenticate using SASL (unknown error)
> (org.apache.zookeeper.ClientCnxn)
> [2018-04-30 20:09:29,531] WARN Session 0x263094512190001 for server null,
> unexpected error, closing socket connection and attempting reconnect
> (org.apache.zookeeper.ClientCnxn)
> java.net.NoRouteToHostException: No route to host
> at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
> at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
> at
> org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)
> at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1141)
> {code}
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