How k8s CPU limits work

What happens when a pod hits 100% CPU?

Everyone knows that once a pod hits 100% of memory, it will be killed by the OOM killer. But did you know what happens with CPU?

Let’s say you have a pod limited to 100mCPU. What actually happens under the hood?

Understanding CPU Limits in Kubernetes

As per official documentation:

cpu limits are enforced by CPU throttling. When a container approaches its cpu limit, the kernel will restrict access to the CPU corresponding to the container’s limit. Thus, a cpu limit is a hard limit the kernel enforces. Containers may not use more CPU than is specified in their cpu limit.

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