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Jian He commented on YARN-3021: ------------------------------- bq. Explicitly have an external renewer system that has the right permissions to renew these tokens. I think this is the correct long-term solution. RM today happens to be the renewer. But we need a central renewer component so that we can do cross-cluster renewals. bq. RM can simply inspect the incoming renewer specified in the token and skip renewing those tokens if the renewer doesn't match it's own address I think in this case, the renewer specified in the token is the same as the RM. IIUC, the JobClient will request the token from B cluster, but still specify the renewer as the A cluster RM (via the A cluster local config), am I right? > 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-3021.002.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. -- This message was sent by Atlassian JIRA (v6.3.4#6332)