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Date: Sat, 17 Jun 2017 05:25:01 +0000 (UTC)
From: "ASF GitHub Bot (JIRA)" <jira@apache.org>
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Subject: [jira] [Commented] (ZOOKEEPER-2184) Zookeeper Client should
 re-resolve hosts when connection attempts fail
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archived-at: Sat, 17 Jun 2017 05:25:17 -0000


    [ https://issues.apache.org/jira/browse/ZOOKEEPER-2184?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16052696#comment-16052696 ] 

ASF GitHub Bot commented on ZOOKEEPER-2184:
-------------------------------------------

Github user geek101 commented on the issue:

    https://github.com/apache/zookeeper/pull/199
  
    @adyach this patch's goal is to make sure when ever a new connection is being established DNS lookup will be performed. If you have given a hostname in connection string then if the underlying IP is gone the TCP connection will break and new TCP connection will be attempted by Zookeeper code and at this time DNS lookup will again be performed.
    
    I hope this helps if you can post your example of connection string it will be more helpful. Zookeeper connection string is supposed to contain the ZK ensemble set/subset hostnames/ips.


> Zookeeper Client should re-resolve hosts when connection attempts fail
> ----------------------------------------------------------------------
>
>                 Key: ZOOKEEPER-2184
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2184
>             Project: ZooKeeper
>          Issue Type: Bug
>          Components: java client
>    Affects Versions: 3.4.6, 3.5.0
>         Environment: Ubuntu 14.04 host, Docker containers for Zookeeper & Kafka
>            Reporter: Robert P. Thille
>            Assignee: Flavio Junqueira
>              Labels: easyfix, patch
>             Fix For: 3.5.4, 3.6.0, 3.4.11
>
>         Attachments: ZOOKEEPER-2184.patch
>
>
> Testing in a Docker environment with a single Kafka instance using a single Zookeeper instance. Restarting the Zookeeper container will cause it to receive a new IP address. Kafka will never be able to reconnect to Zookeeper and will hang indefinitely. Updating DNS or /etc/hosts with the new IP address will not help the client to reconnect as the zookeeper/client/StaticHostProvider resolves the connection string hosts at creation time and never re-resolves.
> A solution would be for the client to notice that connection attempts fail and attempt to re-resolve the hostnames in the connectString.


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