What happens when a container exceeds the CPU limit?

When a container in an environment, such as Docker or Kubernetes, exceeds the CPU limit, the following effects occur:

• CPU usage restriction: The container is allocated no more than the set CPU limit (for example, 0.5 CPU or 500m in Kubernetes).
• Throttling: If the container tries to use more CPU, the OS kernel limits its execution, reducing its priority or interrupting its execution.
• Performance: The application inside the container may run slower because it does not receive more CPU than allocated.
• In Kubernetes: If the CPU limit is exceeded, the container will not be killed (unlike memory limit exceedance), but its CPU time will be limited.

Thus, exceeding the CPU limit does not lead to the container crashing, but to a decrease in performance due to resource restrictions. This ensures that the container will not consume more CPU than allocated and will not affect other containers on the same host.