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https://issues.apache.org/jira/browse/HDFS-7714?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14310060#comment-14310060
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Chris Nauroth commented on HDFS-7714:
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Thank you for taking this issue, Vinay. I think catching {{EOFException}} is a
fine approach. Changing the {{isAlive}} logic has some other side effects, and
I believe that's what caused the test failures in the last Jenkins run.
> Simultaneous restart of HA NameNodes and DataNode can cause DataNode to
> register successfully with only one NameNode.
> ---------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-7714
> URL: https://issues.apache.org/jira/browse/HDFS-7714
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: datanode
> Affects Versions: 2.6.0
> Reporter: Chris Nauroth
> Assignee: Vinayakumar B
> Attachments: HDFS-7714-001.patch
>
>
> In an HA deployment, DataNodes must register with both NameNodes and send
> periodic heartbeats and block reports to both. However, if NameNodes and
> DataNodes are restarted simultaneously, then this can trigger a race
> condition in registration. The end result is that the {{BPServiceActor}} for
> one NameNode terminates, but the {{BPServiceActor}} for the other NameNode
> remains alive. The DataNode process is then in a "half-alive" state where it
> only heartbeats and sends block reports to one of the NameNodes. This could
> cause a loss of storage capacity after an HA failover. The DataNode process
> would have to be restarted to resolve this.
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