Check cert expiration kubeadm
List all control-plane cert/kubeconfig expiry dates; catch silent apiserver outages early
kubeadm certs check-expiration
more kubeadm
all 5 commands →
Renew all certs then restart
kubeadm certs renew all && systemctl restart kubelet
Plan and apply upgrade
kubeadm upgrade plan && kubeadm upgrade apply v1.30.2
Init HA control-plane endpoint
kubeadm init --control-plane-endpoint "<host>:6443" --upload-certs --pod-network-cidr=10.244.0.0/16
Print fresh join command
kubeadm token create --print-join-command