Simple definition
Cgroups limit and measure the resources consumed by Linux processes.
Technical definition
Controlgroups structure CPU, memory, I/O and other controllers and are widely used by systemd and containers.
What’s the point?.
isolating the consumption of resources between services or containers.
Concrete example
a systemd service receives a memory limit.
Common problems
- OOM triggered.
- limit too low.
- difference cgroup v1/v2.
To be noted: Always adapt the diagnosis to the version of the product and to the architecture actually deployed.