Perform a Version upgrade on Worker Nodes

Now that we have upgraded the control plane, we have to upgrade kubeadm and kubelet on the worker nodes.

Upgrade Kubeadm on Worker Nodes

Important Note: Run all the the kubectl commands from the control plane node. Other commands have to be run the worker nodes.

Step 1: Install required kubeadm version.

Update the package repo.

sudo apt-get update -y

Unhold kubeadm package.

sudo apt-mark unhold kubeadm

Install the specific Kubeadm version. Replce 1.29.2-1.1 with the respective version.

sudo apt-get install -y kubeadm=1.29.2-1.1

Step 2: Upgrade the node using the following command.

sudo kubeadm upgrade node

Upgrade Kubelet on Worker Nodes

Follow the steps given below to upgrade kubelet on the worker nodes

Step 1: Get the worker node name.

k get nodes

Step 2: Drain the worker plane node using the node name and make it unschedulable.

Important Note: Here, node01 is the node name. If you have a different name for your worker node, rename it accordingly..

k drain node01 --ignore-daemonsets --delete-emptydir-data

The --delete-emptydir-data flag instructs the drain process to remove any data stored in emptyDir volumes when draining a node..

Note: During CKA exam, you dont have to use the --delete-emptydir-data flag.

Step 3: Unhold Kubelet.

sudo apt-mark unhold kubelet

Step 4: Update and install Kubelet. Replace 1.29.2-1.1 with the required version.

sudo apt-get update -y
sudo apt-get install kubelet=1.29.2-1.1

Step 5: Restart kubelet

sudo systemctl daemon-reload
sudo systemctl restart kubelet

Step 6: Uncordon the node so that node01 becomes schedulable.

k uncordon node01

Step 6: Verify the upgrade using the following command

k get nodes -o wide

You should see the updated version as shown below.