What is cgroups?

Control Groups (cgroups) is a Linux kernel feature that limits, accounts for, and isolates the CPU, memory, disk I/O, and network usage of a group of processes. Docker and Kubernetes use cgroups to enforce container resource limits — when you set requests and limits in a Pod spec, K8s translates those into cgroup settings on the host. OOMKilled errors happen when a container's memory cgroup limit is exceeded.