kubeadm certs check-expiration
kubeadm certs renew all
systemctl restart kubelet ( or other api server etc)
re-generate .kube/config
# ssh <control-node1-cluster1>
# sudo kubeadm kubeconfig user –client-name kubernetes-admin –org=system:masters > ./kube/config
Reference
https://www.linkedin.com/pulse/how-regenerate-kubeconfig-vadim-tsarfin-ygg9e/