kubelet is a process that runs on each node that takes responsibility for the state of that node. It starts and stops containers as directed by the master, and ensures that its containers remain healthy. It will also track the state of each of its pods, and if a pod is not in its desired state, it will be redeployed. kubelet must also relay its health to the master every few seconds. If the master sees that a node has failed (i.e. kubelet has failed to report that the node is healthy), controllers will see this change and relaunch pods on healthy nodes.