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  1. Core Server
  2. SERVER-14149

isMaster may report an incorrect master

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Gone away
    • Affects Version/s: 2.7.1
    • Fix Version/s: None
    • Component/s: Replication
    • Labels:
    • Environment:
      Linux localhost.localdomain 3.14.4-200.fc20.x86_64 #1 SMP Tue May 13 13:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
    • Operating System:
      ALL

      Description

      A replica may report itself as primary (via isMaster), but when stepDown is issued the command execution fails with "not primary can't step down".

      https://github.com/dcci/mongo-replication-perf/blob/master/stepDown.py
      can be used to reproduce.

      Output:

      localhost:30002 5.686825037
      [...]
      localhost:30001 5.59844589233
      localhost:30002 5.70268511772
      command SON([('replSetStepDown', 30)]) failed: not primary so can't step down
      {u'hosts': [u'localhost:30002', u'localhost:30003', u'localhost:30001'],
       u'ismaster': False,
       u'localTime': datetime.datetime(2014, 6, 2, 22, 52, 13, 153000),
       u'maxBsonObjectSize': 16777216,
       u'maxMessageSizeBytes': 48000000,
       u'maxWireVersion': 2,
       u'maxWriteBatchSize': 1000,
       u'me': u'localhost:30002',
       u'minWireVersion': 0,
       u'ok': 1.0,
       u'primary': u'localhost:30003',
       u'secondary': True,
       u'setName': u'rs0',
       u'setVersion': 1}

      I bisected the tree to find the commit that caused the problem and we've a culprit:

      commit c27f26b7b49714649800a7d602fead7d57ca3805
      Author: matt dannenberg <matt.dannenberg@10gen.com>
      Date:   Fri May 23 05:23:13 2014 -0400
       
          SERVER-14042 decrease yea delay from 30 seconds to 3

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            Assignee:
            matt.dannenberg Matt Dannenberg
            Reporter:
            davide.italiano Davide Italiano
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              Dates

              Created:
              Updated:
              Resolved: