In a Kubernetes cluster, there is a Deployment Controller. This controller monitors the instances created by Kubernetes in a cluster. Once a node or the machine hosting the node goes down, Deployment Controller will replace the node.
It is a self-healing mechanism in Kubernetes to provide high availability of applications.
Therefore in Kubernetes cluster, Kubernetes Deployment Controller is responsible for starting the instances as well as replacing the instances in case of a failure.Read the full book at www.amazon.com