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  1. Core Server
  2. SERVER-23862

mongos looses /fails to get updated list from config server repeatedly

    • Type: Icon: Question Question
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 3.2.4
    • Component/s: Sharding
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      On AWS mongos seems to fail connecting to mongo config server after shard servers are added.
      The setup is a test environment in aws

      Config Server and the Mongos are running on two different machines in the same network ( different subnets )

      Config Server # rsconf1/172.31..26.252 --> only 1 node in the replica set
      Mongs service # 172.31.24.126 --> pointing to config server above

      Shard1 # rs1/172.31.43.146
      Shard2 # rs2/172.31.43.147
      Shard # rs3/172.31.45.148

      Only Shard1 add via mongos.

      Mongs successfully connects to config server and then immediately fail to retrieve the list of shards

      2016-04-21T21:57:05.979+0000 I ASIO     [NetworkInterfaceASIO-ShardRegistry-0] Successfully connected to 172.31.26.252:27017
      2016-04-21T21:57:06.188+0000 I SHARDING [Balancer] caught exception while doing balance: could not get updated shard list from config server due to Operation timed out
      2016-04-21T21:57:06.189+0000 I SHARDING [Balancer] about to log metadata event into actionlog: { _id: "ip-172-31-24-126-2016-04-21T21:57:06.189+0000-57194cb2534cef5db40b623e", server: "ip-172-31-24-126", clientAddr: "", time: new Date(1461275826189), what: "balancer.round", ns: "", details: { executionTimeMillis: 30003, errorOccured: true, errmsg: "could not get updated shard list from config server due to Operation timed out" } }
      

      ---------------------------- $$$$$$$$$$$$$$$$$$$$$$$$ -------------------------

      the operation times out on the config server , the same query passes when run directly connected to mongo config server ..

      2016-04-21T21:59:08.690+0000 I COMMAND  [conn29] command config.$cmd command: find { find: "shards", readConcern: { level: "majority", afterOpTime: { ts: Timestamp 1461274573000|2, t: 5 } }, maxTimeMS: 30000 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:92 locks:{} protocol:op_command 30401ms
      2016-04-21T21:59:08.690+0000 I NETWORK  [conn29] end connection 172.31.24.126:44130 (4 connections now open)
      2016-04-21T21:59:38.084+0000 I NETWORK  [initandlisten] connection accepted from 172.31.24.126:44133 #32 (5 connections now open)
      

      ----------------------------------- $$$$$$$$$$$$$$$$ -----------------------------

      Note: mongo config server is running on an EBS backed storage. Even then it should take 30 seconds to return the sharded list, the same query when run on the terminal locally connected returns in fraction of a second.

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            Reporter:
            ppeddada pavan
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              Created:
              Updated:
              Resolved: