Upgrading an existing Cluster¶

upgrade kubeadm-based Cluster¶

只能小版本更新
- 1.21 -> 1.22 ✅
- 1.21 -> 1.23 ❌
一定要阅读changelog https://github.com/kubernetes/kubernetes/tree/master/CHANGELOG

检查当前版本：

kubectl version –short
kubectl get nodes
kubeadm version

Upgrade Control Plane¶

update kubeadm package
Drain the control plane/master node
kubeadm upgrade plan
kubeadm upgrade apply
Uncordon the control plan/master node
update kubelet and kubectl

以Ubuntu为例

# update kubeadm
sudo apt-mark unhold kubeadm
sudo apt-get update
sudo apt-cache policy kubeadm
sudo apt-get install -y kubeadm=$TARGET_VERSION
sudo apt-mark hold kubeadm

# drain master node
kubectl drain k8s-master --ignore-daemonsets

sudo kubeadm upgrade plan
sudo kubeadm upgrade apply v$TARGET_VERSION

# uncordon
kubectl uncordon k8s-master

# update kubelet and kubectl
sudo apt-mark unhold kubelet kubectl
sudo apt-get update
sudo apt-get install -y kubelet=$TARGET_VERSION kubectl=$TARGET_VERSION
sudo apt-mark hold kubelet kubectl

Upgrade work node¶

以Ubuntu为例

# go to master node
kubectl drain k8s-worker1 --ingore-daemonsets

# update kubeadm
sudo apt-mark unhold kubeadm
sudo apt-get update
sudo apt-get install -y kubeadm=$TARGET_VERSION
sudo apt-mark hold kubeadm

sudo kubeadm upgrade node

# update kubelet and kubectl
sudo apt-mark unhold kubelet
sudo apt-get update
sudo apt-get install -y kubelet=$TARGET_VERSION
sudo apt-mark hold kubelet

# go to master node, uncordon this node
kubectl uncordon k8s-worker1

Worker Node Maintenance¶

os update and hardware upgrade

Drain/Cordon the Node.