What does the kubelet do in a Kubernetes cluster?

The kubelet is a critical component of a Kubernetes cluster that runs on each node in the cluster. Its primary responsibility is to manage the lifecycle of containers, ensuring that they are running as expected. The kubelet takes instructions from the Kubernetes API server and supervises the containers that are part of the Pods scheduled on its node.

This includes starting, stopping, and maintaining containers, monitoring their health, and reporting the status back to the control plane. By consistently executing these tasks, the kubelet ensures that the desired state of the applications running in the cluster is maintained, effectively aligning the operational reality with the desired configuration as specified in the Pod specifications.

Other options do not accurately describe the role of the kubelet. For example, scheduling Pods is mainly handled by the kube-scheduler rather than the kubelet. While kubelet does report some metrics, application performance monitoring is typically managed by other tools within the Kubernetes ecosystem. Additionally, network policies are managed primarily by Kubernetes network plugins and controllers, rather than the kubelet itself. This clarity on the responsibilities of the kubelet helps establish a clear understanding of its pivotal role within the Kubernetes architecture.