25.9. Using systemd unit files to set limits for applications

Procedure

1. Edit the /usr/lib/systemd/system/example.service file to limit the memory usage of a service:

   …​
   [Service]
   MemoryMax=1500K
   …​

   The configuration limits the maximum memory that the processes in a control group cannot exceed. The example.service service is part of such a control group which has imposed limitations. You can use suffixes K, M, G, or T to identify Kilobyte, Megabyte, Gigabyte, or Terabyte as a unit of measurement.

2. Reload all unit configuration files:

   # systemctl daemon-reload

3. Restart the service:

   # systemctl restart example.service

Verification

1. Check that the changes took effect:

   # cat /sys/fs/cgroup/system.slice/example.service/memory.max
   1536000

   This output shows that the memory consumption was limited at around 1,500 KB.