Upgrade kubernetes cluster

15 June 2023

So what are we going to do ?

We will upgrade kubernetes cluster from v1.26.0 to v1.27.0.

essentially the upgrade involves installation of kubeadm, kubectl and kubelet packages.

Following are the phases involved during this version upgrade :-

We will setup the 4 node k8s cluster locally you can checkout k8s-1.3-initialize-and-setup-k8s-cluster.md post on how to set it up.

steps to upgrade control node:-

drain the control node using

kubectl drain CONTROL_NODE --skip-daemonsets
install kubeadm package with the v1.27.0 on the control node.

sudo apt-get install kubeadm=1.27.0-00
upgrade the node components using on the control node.

kubeadm upgrade apply v1.27.0
install the kubelet and kubectl v1.27.0 packages on the control node.

sudo apt-get install kubelet=1.27.0-00 kubectl=1.27.0-00
reload system daemon and restart the kubelet on the control node.
```
systemctl daemon-reload
systemctl restart kubelet
```
uncordon the control node.

kubectl uncordon CONTROL_NODE

steps to upgrade worker node:-

drain the worker node

kubectl drain WORKER_NODE --skip-daemonsets
install kubeadm package with the v1.27.0 on the worker node.

sudo apt-get install kubeadm=1.27.0-00
upgrade the node components using on the worker node.

kubeadm upgrade node
install the kubelet and kubectl v1.27.0 packages on the worker node.

sudo apt-get install kubelet=1.27.0-00 kubectl=1.27.0-00

reload system daemon and restart the kubelet.

systemctl daemon-reload
systemctl restart kubelet