kubeadmUp.md

Kubeadm

Worker nodes, update strategy

1. All at once
2. One at the time
3. Add a new Node for overflow, migrate each node

Upgrade summary

1. Upgrade kubeadm tool
2. Upgrade master
3. Upgrade worker
4. Upgrade kubelet 

Upgrade execution

1) Upgrade kubeadm tool
	a. apt update
	apt install kubeadm=1.20.0-00
		i. apt upgrade -y kubeadm =1.12.0-00
2) Upgrade master
	a. Kubeadm upgrade plan
	b. kubectl drain <node-to-drain> --ignore-daemonsets
	c. Kubeadm upgrade apply v1.12.0
	d. Upgrade the kubelet if exist in the master
		i. apt upgrade -y kubelet=1.12.0-00
		ii. systemctl restart kubelet
3) Upgrade worker
	a. ssh node-1
	b. sudo kubeadm upgrade node
    apt update
	c. apt install kubeadm=1.20.0-00
	d. kubectl drain <node-to-drain> --ignore-daemonsets
	e. kubeadm upgrade node
	f. Upgrade the kubelet if exist in the master
		i. apt upgrade -y kubelet=1.12.0-00
		ii. systemctl daemon-reload
		iii. systemctl restart kubelet
        kubectl uncordon node01