title: could not get updated shard list from config server due to Operation timed out
body: <blockquote>
    <p>mongodb:v3.4.9 </p>
  </blockquote>
  
  <p>error logs from mongodb c++ source code: <a href="https://github.com/mongodb/mongo/blob/367d31e1da549c460ae710a8cc280f4c235ab24f/src/mongo/s/client/shard_registry.cpp#L384" rel="nofollow noreferrer">https://github.com/mongodb/mongo/blob/367d31e1da549c460ae710a8cc280f4c235ab24f/src/mongo/s/client/shard_registry.cpp#L384</a></p>
  
  <p>Mongos throw error when i add new node to a shard cluster and all the enableShardCollection can't query (<em>ExceededTimeLimit</em>).</p>
  
  <p>It's can be repaired?</p>
  
  <blockquote>
    <p>Marking host  config.app.com as failed :: caused by :: ExceededTimeLimit: Operation timed out, request was RemoteCommand 871 -- target:config.app.com db:config expDate:2017-10-21T13:16:38.250+0000 cmd:{ find: "shards", readConcern: { level: "majority", afterOpTime: { ts: Timestamp 1508586527000|1, t: 24 } }, maxTimeMS: 30000 }</p>
    
    <p>2017-10-21T13:16:38.250+0000 I SHARDING [shard registry reload] Operation timed out  :: caused by :: ExceededTimeLimit: Operation timed out, request was RemoteCommand 871 -- target:config.app.com db:config expDate:2017-10-21T13:16:38.250+0000 cmd:{ find: "shards", readConcern: { level: "majority", afterOpTime: { ts: Timestamp 1508586527000|1, t: 24 } }, maxTimeMS: 30000 }</p>
    
    <p>2017-10-21T13:16:38.250+0000 I SHARDING [shard registry reload] Periodic reload of shard registry failed  :: caused by :: 50 could not get updated shard list from config server due to Operation timed out, request was RemoteCommand 871 -- target:config.app.com db:config expDate:2017-10-21T13:16:38.250+0000 cmd:{ find: "shards", readConcern: { level: "majority", afterOpTime: { ts: Timestamp 1508586527000|1, t: 24 } }, maxTimeMS: 30000 }; will retry after 30s</p>
  </blockquote>