Happy New Year!
Version using 4.2.8
Our all mongos suddenly stopped working, unable to connect and we were receiving constantly these messages:
NETWORK [conn1524750] DBException handling request, closing client connection: ClientDisconnect: operation was interrupted.
SHARDING [PeriodicShardedIndexConsistencyChecker] Attempt 0 to check index consistency for DBname.Collname received StaleShardVersion error :: caused by :: StaleConfig
We logged these jira, but we are not sure if this is required flushrouter config or some hmac key refresh issue.
So after some digging, I found these articles that stated flush required, because sometime metadata did not get updated across all the cluster.
But we did not have any of the drop database and other conditions except getShardDistribution commands.