To renew the Kubernetes certificates, you can use the below commands (or refer to the official kubernetes documentation Certificate Management with kubeadm for more details on this):
To renew all certs for clusters with kubernetes version 1.19 or earlier, run:
$ kubeadm alpha certs renew all
And for clusters running kubernetes version 1.20 or above, run:
$ kubeadm certs renew all
To verify that certs have been renewed for clusters with kubernetes version 1.19 or earlier, run the below command:
$ kubeadm alpha certs check-expiration
And for cluster running kubernetes version 1.20 or above, run:
$ kubeadm certs check-expiration