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https://issues.apache.org/jira/browse/HDFS-7597?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daryn Sharp updated HDFS-7597:
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Attachment: HDFS-7597.patch
The test failure was due to the test wanting to verify whether the NN would
stomp the service addr in the token. The same token is used twice, once
expecting the service to be changed, second not changed. Since the token ident
is the same, the now cached ugi has associated the ident with two services. I
simply made a new token for the "don't stomp the service" check since this
condition was induced by the test doing something that won't happen in practice.
> Clients seeking over webhdfs may crash the NN
> ---------------------------------------------
>
> Key: HDFS-7597
> URL: https://issues.apache.org/jira/browse/HDFS-7597
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: webhdfs
> Affects Versions: 2.0.0-alpha
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
> Priority: Critical
> Attachments: HDFS-7597.patch, HDFS-7597.patch
>
>
> Webhdfs seeks involve closing the current connection, and reissuing a new
> open request with the new offset. The RPC layer caches connections so the DN
> keeps a lingering connection open to the NN. Connection caching is in part
> based on UGI. Although the client used the same token for the new offset
> request, the UGI is different which forces the DN to open another unnecessary
> connection to the NN.
> A job that performs many seeks will easily crash the NN due to fd exhaustion.
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