We are running 3Shard Mongo Cluster in our lab - QA environment before we go live.
The configuration is simple and straightforward.
3 shard system - each shard with its replica systems - 3 servers, 2 backing each other and the 3rd one as arbiter.
The config server is running in a non replica set mode, given the setup is experimental.
Mongos is running on its own instance.
All servers are in AWS
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3 - Shard System : M3.Medium - 4 Core/15 Gig
failover and Arbiter on a lower configuration
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Config Server on a M3.Medium - 4 Core/15Gig
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Mongos Server on a t2.Medium - diskless
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Mongos seems to be shutting down with no details or errors . All we see in the log is
Can't use connection pool during shutdown
2016-05-03T04:43:02.586+0000 I SHARDING [signalProcessingThread] dbexit: rc:0
1) What is not clear from this message is, is the app trying to get a connection and Mongos can't serve it ?
2) Is Mongo unable to get connections from Config Server ? -- No indication of errors or whatsoever in the logs ..
3) Is Mongos failing to get connections to Shard Servers ? --- There is no such indication in any of the shard logs ..
Has anybody faced similar situation with Mongo Cluster ? We are going to move the mongos to a multiple servers for redundancy, most likely deploy Mongos on multiple app servers and load balance it. We would however like to know what may be causing the shutdown.
Thanks