Informationetcd should be configured to make use of TLS encryption for client connections.
etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive in nature and should be protected by client authentication. This requires the API server to identify itself to the etcd server using a client certificate and key.
SolutionFollow the Kubernetes documentation and set up the TLS connection between the apiserver and etcd. Then, edit the `/etc/kubernetes/apiserver` file on the master node and set the `KUBE_API_ARGS` parameter to include `'--etcd-certfile='` and `'--etcd-keyfile='`: `KUBE_API_ARGS='... --etcd-certfile= --etcd-keyfile= ...'`
Based on your system, restart the `kube-apiserver` service. For example: `systemctl restart kube-apiserver.service`
TLS and client certificate authentication must be configured for etcd.