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https://issues.apache.org/jira/browse/YARN-3021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14367669#comment-14367669
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Yongjun Zhang commented on YARN-3021:
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Hi [~jianhe],
Thanks for your comment. I'm actually aligned with what you suggested.
The problem I was trying to point out is, we will have to change the behavior
of the code I pasted above to deal with null renewer. E.g., the
{{getRenewer()}} method will return a non-null based on current implementation
(if not set or found, TRIVIAL_RENEWER will be returned); after making the
suggested change for this jira, the renewer can be null, so we should return
null from {{getRenewer()}}.
My question was, I'm not sure about the impact of this behavior change. I
expect some application does count on the current behavior.
More comments?
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
> Assignee: Yongjun Zhang
> 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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