MongoDB server is restarting repeatedly due to systemd-triggered shutdowns

We have observed multiple unexpected graceful shutdowns of the MongoDB service on the server.
After investigation, we found that these shutdowns are being triggered by systemd sending SIGTERM to the mongod process.

{"t":{"$date":"2025-07-15T06:18:20.602+00:00"},"s":"I","c":"CONTROL","id":23377,"ctx":"SignalHandler","msg":"Received signal","attr":{"signal":15,"error":"Terminated"}}

Recent Shutdown Log Samples:

Mar 06 13:29:45 systemd[1]: Stopped mongod.service - MongoDB Database Server.
Mar 06 13:36:36 systemd[1]: Stopped mongod.service - MongoDB Database Server.
May 29 06:30:43 systemd[1]: Stopped mongod.service - MongoDB Database Server.
Jul 09 06:21:55 systemd[1]: Stopped mongod.service - MongoDB Database Server.
Jul 15 06:18:37 systemd[1]: Stopped mongod.service - MongoDB Database Server.

Initial Investigation:

  • These are graceful shutdowns, not crashes or OOM kills.
  • The signal SIGTERM (15) is consistently sent by PID 1 (systemd), not by MongoDB itself or an external process.

Request:
Please assist in identifying and preventing these repeated systemd-triggered shutdowns.

Check this thread and also others on signal 15

Mongo shuts down with signal 15