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https://issues.apache.org/jira/browse/YARN-3021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14350013#comment-14350013
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Yongjun Zhang commented on YARN-3021:
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Hi [~jianhe],
{quote}
My only concern is not to add a user-facing API only used for short-term.
{quote}
I thought about it a bit more, it seems that
"mapreduce.job.hdfs-servers.token-renewal.exclude" is still going to be a
user-facing API only used for short-term, because when we introduce external
renewer, the tokens need to be assigned to the renewer, after all, we want the
tokens to be renewed. Right? Or there are use cases that we really don't want
to renew?
That said, I think the solution would solve our current problem.
Thanks.
> YARN's delegation-token handling disallows certain trust setups to operate
> properly over DistCp
> -----------------------------------------------------------------------------------------------
>
> 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-3021.002.patch,
> YARN-3021.003.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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