Hadoop HDFS
  1. Hadoop HDFS
  2. HDFS-1965

IPCs done using block token-based tickets can't reuse connections

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Critical Critical
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.22.0
    • Component/s: security
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      This is the reason that TestFileConcurrentReaders has been failing a lot. Reproducing a comment from HDFS-1057:

      The test has a thread which continually re-opens the file which is being written to. Since the file's in the middle of being written, it makes an RPC to the DataNode in order to determine the visible length of the file. This RPC is authenticated using the block token which came back in the LocatedBlocks object as the security ticket.

      When this RPC hits the IPC layer, it looks at its existing connections and sees none that can be re-used, since the block token differs between the two requesters. Hence, it reconnects, and we end up with hundreds or thousands of IPC connections to the datanode.

      1. hdfs-1965-0.22.txt
        9 kB
        Todd Lipcon
      2. hdfs-1965.txt
        11 kB
        Todd Lipcon
      3. hdfs-1965.txt
        9 kB
        Todd Lipcon
      4. hdfs-1965.txt
        8 kB
        Todd Lipcon

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            • Assignee:
              Todd Lipcon
              Reporter:
              Todd Lipcon
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                Updated:
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