# On master - See https://kubernetes.io/docs/setup/certificates/#all-certificates
# Generate the new certificates - you may have to deal with AWS - see above re extra certificate SANs
sudo kubeadm alpha certs renew apiserver
sudo kubeadm alpha certs renew apiserver-etcd-client
sudo kubeadm alpha certs renew apiserver-kubelet-client
sudo kubeadm alpha certs renew front-proxy-client
# Generate new kube-configs with embedded certificates - Again you may need extra AWS specific content - see above
sudo kubeadm alpha kubeconfig user --org system:masters --client-name kubernetes-admin > admin.conf
sudo kubeadm alpha kubeconfig user --client-name system:kube-controller-manager > controller-manager.conf
sudo kubeadm alpha kubeconfig user --org system:nodes --client-name system:node:$(hostname) > kubelet.conf
sudo kubeadm alpha kubeconfig user --client-name system:kube-scheduler > scheduler.conf
# chown and chmod so they match existing files
sudo chown root:root {admin,controller-manager,kubelet,scheduler}.conf
sudo chmod 600 {admin,controller-manager,kubelet,scheduler}.conf
# Move to replace existing kubeconfigs
sudo mv admin.conf /etc/kubernetes/
sudo mv controller-manager.conf /etc/kubernetes/
sudo mv kubelet.conf /etc/kubernetes/
sudo mv scheduler.conf /etc/kubernetes/
# Restart the master components
sudo kill -s SIGHUP $(pidof kube-apiserver)
sudo kill -s SIGHUP $(pidof kube-controller-manager)
sudo kill -s SIGHUP $(pidof kube-scheduler)
# Verify master component certificates - should all be 1 year in the future
# Cert from api-server
echo -n | openssl s_client -connect localhost:6443 2>&1 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | openssl x509 -text -noout | grep Not
# Cert from controller manager
echo -n | openssl s_client -connect localhost:10257 2>&1 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | openssl x509 -text -noout | grep Not
# Cert from scheduler
echo -n | openssl s_client -connect localhost:10259 2>&1 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | openssl x509 -text -noout | grep Not
# Generate kubelet.conf
sudo kubeadm alpha kubeconfig user --org system:nodes --client-name system:node:$(hostname) > kubelet.conf
sudo chown root:root kubelet.conf
sudo chmod 600 kubelet.conf
# Drain
kubectl drain --ignore-daemonsets $(hostname)
# Stop kubelet
sudo systemctl stop kubelet
# Delete files
sudo rm /var/lib/kubelet/pki/*
# Copy file
sudo mv kubelet.conf /etc/kubernetes/
# Restart
sudo systemctl start kubelet
# Uncordon
kubectl uncordon $(hostname)
# Check kubelet
echo -n | openssl s_client -connect localhost:10250 2>&1 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' | openssl x509 -text -noout | grep Not