Pod Overhead

Pod Overhead is a way to account for the resources consumed by the Pod infrastructure on top of the container requests and limits.

Stuff you wanna know:

1. A Pod’s overhead is set at admission time according to the overhead associated with the Pod’s RuntimeClass.
2. The kubelet will include the Pod overhead when sizing the Pod cgroup, and when carrying out Pod eviction ranking.
3. To work with Pod overhead, you need a RuntimeClass that defines the overhead field.
4. When the kube-scheduler is deciding which node should run a new Pod, the scheduler considers that Pod’s overhead as well as the sum of container requests for that Pod.
5. Once a Pod is scheduled to a node, the kubelet on that node creates a new cgroup for the Pod. It is within this pod that the underlying container runtime will create containers.

More stuff:

• Pod Overhead — https://kubernetes.io/docs/concepts/scheduling-eviction/pod-overhead/
• Configuring Pod overhead — https://kubernetes.io/docs/concepts/scheduling-eviction/pod-overhead/#set-up
• Verify Pod cgroup limits — https://kubernetes.io/docs/concepts/scheduling-eviction/pod-overhead/#verify-pod-cgroup-limits
• PodOverhead Design enhancement proposal — https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/688-pod-overhead