References

• *Upgrading kubeadm clusters

For example, Upgrade 1.21.00 to 1.21.1

Upgrade All Kubernetes Components on the Control Node

1. Download kubeadm version

    sudo apt-get update && \
    sudo apt-get install -y --allow-change-held-packages kubeadm=1.21.1-00
   

2. Drain the control plane node:

    kubectl drain acgk8s-control --ignore-daemonsets
   

3. Check whether the components are upgradeable to v1.21.1:

    sudo kubeadm upgrade plan v1.21.1
   

4. Apply the upgrade:

    sudo kubeadm upgrade apply v1.21.1
   

5. Upgrade kubelet and kubectl:

    sudo apt-get update && \
    sudo apt-get install -y --allow-change-held-packages kubelet=1.21.1-00 kubectl=1.21.1-00
   

6. Reload daemons

    sudo systemctl daemon-reload
   

7. Restart kubelet:

    sudo systemctl restart kubelet
   

8. Uncordon the control plane node:

    kubectl uncordon acgk8s-control
   

Upgrade All Kubernetes Components on the Worker Node

1. Drain the worker1 node:

    kubectl drain acgk8s-worker1 --ignore-daemonsets --force
   

2. SSH into the Worker node:

    ssh acgk8s-worker1
   

3. Install a new version of kubeadm:

    sudo apt-get update && \
    sudo apt-get install -y --allow-change-held-packages kubeadm=1.21.1-00
   

4. Upgrade the node:

    sudo kubeadm upgrade node
   

5. Upgrade kubelet and kubectl:

    sudo apt-get update && \
    sudo apt-get install -y --allow-change-held-packages kubelet=1.21.1-00 kubectl=1.21.1-00
   

6. Reload daemon

   sudo systemctl daemon-reload
   

7. Restart kubelet:

    sudo systemctl restart kubelet
   

8. Type exit to exit the node.

9. Uncordon the node:

   kubectl uncordon acgk8s-worker1
   

10. Repeat the process above for other worker nodes