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https://issues.apache.org/jira/browse/YARN-3021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14296041#comment-14296041
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Robert Kanter commented on YARN-3021:
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{quote}I don't see any security holes. This token is only for the application's
own use. The validation and renewal that you are turning off via the new
parameter should not impact security of YARN or other applications.{quote}
I'm not sure that's entirely correct. We're talking about the HDFS delegation
token, right? Might it be possible to circumvent token expiration times by
telling YARN not to renew the token? I'm not sure when the expiration check is
done, so I could be wrong here.
> YARN's delegation-token handling disallows certain trust setups to operate
> properly
> -----------------------------------------------------------------------------------
>
> Key: YARN-3021
> URL: https://issues.apache.org/jira/browse/YARN-3021
> Project: Hadoop YARN
> Issue Type: Bug
> Components: security
> Affects Versions: 2.3.0
> Reporter: Harsh J
> Attachments: YARN-3021.001.patch, YARN-3021.patch
>
>
> Consider this scenario of 3 realms: A, B and COMMON, where A trusts COMMON,
> and B trusts COMMON (one way trusts both), and both A and B run HDFS + YARN
> clusters.
> Now if one logs in with a COMMON credential, and runs a job on A's YARN that
> needs to access B's HDFS (such as a DistCp), the operation fails in the RM,
> as it attempts a renewDelegationToken(…) synchronously during application
> submission (to validate the managed token before it adds it to a scheduler
> for automatic renewal). The call obviously fails cause B realm will not trust
> A's credentials (here, the RM's principal is the renewer).
> In the 1.x JobTracker the same call is present, but it is done asynchronously
> and once the renewal attempt failed we simply ceased to schedule any further
> attempts of renewals, rather than fail the job immediately.
> We should change the logic such that we attempt the renewal but go easy on
> the failure and skip the scheduling alone, rather than bubble back an error
> to the client, failing the app submission. This way the old behaviour is
> retained.
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