Hi Team,
We have configured a PMM user for monitoring the MongoDB replica set. After a few days, we noticed that the replica set ran out of maximum available connections.
It appears that each node in the replica set is continuously checking the status of the other nodes every few seconds, which is creating a high number of connections. This eventually led to the entire replica set becoming unavailable.
Since MongoDB does not currently have user-level connection limits configured in our environment, we need your help to understand whether it is possible to configure minimum/maximum connection limits specifically for the PMM monitoring user to avoid exhausting the available connections.
In our case, each node triggered around 1000 connections. so, at the end we disabled the PMM agent and killed all the connections. Just FYI.. we are not seeing any issues with Standalone environment.
Please let us know the recommended approach or best practices for configuring PMM monitoring connections in MongoDB.
Set up :
MongoDB 8.0.20 Community edition
Rocky Linux 9
PMM Server and Client Version: 3.2.0