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https://issues.apache.org/jira/browse/HADOOP-14441?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16904264#comment-16904264
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Wei-Chiu Chuang commented on HADOOP-14441:
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[~tartina] depending on your applications,
you could apply this patch to your Hadoop installation (2.7 is EOL, I think),
or call FileSystem.addDelegationTokens() multiple times (depending on the
number of KMS instances) to get delegation tokens from all KMS.
This is actually not a problem for MapReduce, because MR unintentionally calls
FileSystem.addDelegationTokens() three times.
> LoadBalancingKMSClientProvider#addDelegationTokens should add delegation
> tokens from all KMS instances
> ------------------------------------------------------------------------------------------------------
>
> Key: HADOOP-14441
> URL: https://issues.apache.org/jira/browse/HADOOP-14441
> Project: Hadoop Common
> Issue Type: Bug
> Components: kms
> Affects Versions: 2.7.0
> Environment: CDH5.7.4, Kerberized, SSL, KMS-HA, at rest encryption
> Reporter: Wei-Chiu Chuang
> Assignee: Wei-Chiu Chuang
> Priority: Major
> Attachments: HADOOP-14441.001.patch, HADOOP-14441.002.patch,
> HADOOP-14441.003.patch, HADOOP-14441.004.patch
>
>
> LoadBalancingKMSClientProvider only gets delegation token from one KMS
> instance, in a round-robin fashion. This is arguably a bug, as JavaDoc for
> {{KeyProviderDelegationTokenExtension#addDelegationTokens}} states:
> {quote}
> /**
> * The implementer of this class will take a renewer and add all
> * delegation tokens associated with the renewer to the
> * <code>Credentials</code> object if it is not already present,
> ...
> **/
> {quote}
> This bug doesn't pop up very often, because HDFS clients such as MapReduce
> unintentionally calls {{FileSystem#addDelegationTokens}} multiple times.
> We have a custom client that accesses HDFS/KMS-HA using delegation token, and
> we were puzzled why it always throws "Failed to find any Kerberos tgt"
> exceptions talking to one KMS but not the other. Turns out that client
> couldn't talk to the KMS because {{FileSystem#addDelegationTokens}} only gets
> one KMS delegation token at a time.
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