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https://issues.apache.org/jira/browse/HDFS-4009?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13474982#comment-13474982
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Daryn Sharp commented on HDFS-4009:
-----------------------------------
I'm not sure anything more complicated is needed than what it is currently
there. Each token has its own independent expiration time, so batching them up
doesn't seem to be of value esp. since there should generally be only one.
Each token also knows how to renew itself, so bundling it up with its renewer
also seems unnecessary.
I think it's back to the renewer is a singleton. Hftp/Webhdfs register their
token on init, and cancel/unregister on close. I'd lazy start the renewer when
a token is registered, and shut it down when the last one is removed.
> WebHdfsFileSystem and HftpFileSystem don't need delegation tokens
> -----------------------------------------------------------------
>
> Key: HDFS-4009
> URL: https://issues.apache.org/jira/browse/HDFS-4009
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 2.0.0-alpha
> Reporter: Tom White
> Assignee: Karthik Kambatla
> Attachments: hadoop-8852.patch, hadoop-8852.patch,
> hadoop-8852-v1.patch
>
>
> Parent JIRA to track the work of removing delegation tokens from these
> filesystems.
> This JIRA has evolved from the initial issue of these filesystems not
> stopping the DelegationTokenRenewer thread they were creating.
> After further investigation, Daryn pointed out - "If you can get a token, you
> don't need a token"! Hence, these filesystems shouldn't use delegation tokens.
> Evolution of the JIRA is listed below:
> Update 2:
> DelegationTokenRenewer is not required. The filesystems that are using it
> already have Krb tickets and do not need tokens. Remove
> DelegationTokenRenewer and all the related logic from WebHdfs and Hftp
> filesystems.
> Update1:
> DelegationTokenRenewer should be Singleton - the instance and renewer threads
> should be created/started lazily. The filesystems using the renewer shouldn't
> need to explicity start/stop the renewer, and only register/de-register for
> token renewal.
> Initial issue:
> HftpFileSystem and WebHdfsFileSystem should stop the DelegationTokenRenewer
> thread when they are closed.
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