Kubernetes supports the use of secure communication channels between the API server and any client, including the nodes themselves. Whether it's a GUI or command-line utility such as kubectl, we can use certificates to communicate with the API server. Hence, the API server is the central interaction point for any changes to the cluster and is a critical component to secure.

In deployments such as GCE, the kubelet on each node is deployed for secure communication by default. This setup uses TLS bootstrapping and the new certificates' API to establish a secure connection with the API server using TLS client certificates and a Certificate Authority (CA) cluster.