I created a client in Ruby configured to establish 20,000 connections to local replica set servers (PSSA), as follows:
At about 6,000 connections per each of the servers, the servers start closing connections. Looking in the server log I see:
This message appears to be produced in src/mongo/transport/service_entry_point_utils.cpp:
The above code appears to discard the root cause of the error, making further troubleshooting impossible.
As a MongoDB user I would like the server to provide error messages that indicate the cause of the problem, so that I can troubleshoot the problems.