[jira] [Resolved] (HDFS-5850) DNS Issues during TrashEmptier initialization can silently leave it non-functional

["Kihwal Lee (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HDFS-5850?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kihwal Lee resolved HDFS-5850.
------------------------------

    Resolution: Won't Fix

I don't think we need to fix this in 0.23, if it is already fixed in 2.x.

> DNS Issues during TrashEmptier initialization can silently leave it non-functional
> ----------------------------------------------------------------------------------
>
>                 Key: HDFS-5850
>                 URL: https://issues.apache.org/jira/browse/HDFS-5850
>             Project: Hadoop HDFS
>          Issue Type: Bug
>    Affects Versions: 0.23.0
>            Reporter: Kihwal Lee
>            Priority: Critical
>
> [~knoguchi] recently noticed that the trash directories of a restarted cluster were not cleaned up. It turned out that it was caused by a transient DNS problem during initialization.
> TrashEmptier thread in namenode is actually a FileSystem client running in a loop, which makes RPC calls to itself in order  to list, rename and delete trash files.  In a secure setup, the client needs to create the right service principal name for the namenode for making a RPC connection. If there is a DNS issue at that moment, the SPN ends up with the IP address, not the fqdn.
> Since KDC does not recognize this SPN, TrashEmptier does not work from that point on. I verified that the SPN with the IP address was what the TrashEmptier thread asked KDC for a service ticket for.



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