Table of contents
- 🗼Introduction
- 🗼Upgrading the Control Plane Node
- 🗼Steps of Upgrading with Kubeadm
- Step 1: Check the Linux Distribution
- Step 2: Add the Kubernetes APT Repository
- Step 3: Add the Kubernetes APT Key
- Step 4: Update the Package List
- Step 5: Find the Latest Patch Release for Kubernetes
- Step 6: Upgrade the Control Plane Nodes
- Step 7: Run the Upgrade Plan
- Step 8: Apply the Upgrade
- Step 9: Upgrade Kubelet and Kubectl
- Step 10: Restart the Upgraded Resources
- 🗼Conclusion
🗼Introduction
Upgrading a Kubernetes cluster is a critical task that ensures you are benefiting from the latest features, security patches, and performance improvements. This blog is the part 1 of Kubernetes cluster upgradation process, in this part will guide you through the process of Control Plan node upgrade, focusing on the best practices and commands needed for a smooth upgrade using kubeadm.
🗼Upgrading the Control Plane Node
The first step in upgrading a Kubernetes cluster is to upgrade the control plane node. During this process:
No new pods can be scheduled.
The cluster is not accessible using
kubectl.No new pods will be created if a pod fails.
Running applications, pods, and nodes are not affected.
🗼Steps of Upgrading with Kubeadm
Step 1: Check the Linux Distribution
First, determine the Linux distribution you are using:
cat /etc/*release*
Step 2: Add the Kubernetes APT Repository
Add the Kubernetes APT repository to your system:
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list
Step 3: Add the Kubernetes APT Key
Add the APT key for the Kubernetes repository:
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
Step 4: Update the Package List
Update the package list:
sudo apt-get update
Step 5: Find the Latest Patch Release for Kubernetes
Find the latest patch release for Kubernetes 1.29 using the OS package manager:
sudo apt update
sudo apt-cache madison kubeadm
Step 6: Upgrade the Control Plane Nodes
Upgrade the kubeadm tool:
sudo apt-mark unhold kubeadm
sudo apt-get update
sudo apt-get install -y kubeadm=1.29.x-*
sudo apt-mark hold kubeadm
Make sure to change the kubeadm version to the one obtained in the previous step.
Step 7: Run the Upgrade Plan
Run the upgrade plan to get information about the update and warnings if something might go wrong:
sudo kubeadm upgrade plan
Step 8: Apply the Upgrade
Apply the upgrade to the control plane:
sudo kubeadm upgrade apply v1.29.x
Make sure to change the version appropriately.
Step 9: Upgrade Kubelet and Kubectl
Upgrade kubelet and kubectl:
sudo apt-mark unhold kubelet kubectl
sudo apt-get update
sudo apt-get install -y kubelet=1.29.x-* kubectl=1.29.x-*
sudo apt-mark hold kubelet kubectl
Step 10: Restart the Upgraded Resources
Finally, restart the upgraded resources to ensure all changes take effect:
sudo systemctl daemon-reload
sudo systemctl restart kubelet
🗼Conclusion
Upgrading your Kubernetes cluster using kubeadm ensures you stay up-to-date with the latest improvements and security patches. By following the steps outlined in this guide, you can perform a smooth and efficient upgrade of both control plane and worker nodes. Remember to always backup your cluster and thoroughly test the upgrade process in a staging environment before applying it to production.