Introduction :-

Upgrading an Amazon Elastic Kubernetes Service (EKS) cluster ensures security, stability, and access to the latest Kubernetes features. This document outlines the step-by-step process to upgrade an AWS EKS cluster with minimal downtime.

Prerequisites :-

Before starting the upgrade process, ensure the following:

• AWS CLI and kubectl are installed and updated.

• IAM permissions allow cluster and node group modifications.

• Workloads are backed up.

• The upgrade is tested in a staging environment before production.

Upgrade Process

1. Check Current Kubernetes Version

Before upgrading, verify the current cluster version:

aws eks describe-cluster --name <cluster-name> --query 'cluster.version'

2. Upgrade the Control Plane

Upgrade to the next minor Kubernetes version:

aws eks update-cluster-version --name <cluster-name> --kubernetes-version <new-version>

Monitor the update process:

aws eks describe-cluster --name <cluster-name> --query 'cluster.status'

3. Update Managed Node Groups

Check the current node group version:

aws eks describe-nodegroup --cluster-name <cluster-name> --nodegroup-name <node-group-name> --query 'nodegroup.version'

Upgrade the node group:

aws eks update-nodegroup-version --cluster-name <cluster-name> --nodegroup-name <node-group-name> --kubernetes-version <new-version>

4. Update Self-Managed Node Groups

Find the recommended Amazon Machine Image (AMI) for your Kubernetes version:

aws ssm get-parameters --names /aws/service/eks/optimized-ami/<k8s-version>/amazon-linux-2/recommended/image_id --region <region>

Drain and terminate old nodes:

kubectl drain <node-name> --ignore-daemonsets --delete-local-data

5. Update kubectl and eksctl

Ensure that you have the latest version of kubectl and eksctl:

curl -LO "https://lnkd.in/dTFpT7_b -L -s https://lnkd.in/dagrzZj9"
chmod +x ./kubectl && mv ./kubectl /usr/local/bin/kubectl

6. Test the Cluster

Verify the nodes in the cluster:

kubectl get nodes -o wide

Run necessary tests to ensure cluster functionality.

Best Practices :-

• Backup workloads before initiating the upgrade process.

• Test the upgrade in a staging environment before applying it to production.

• Monitor cluster health throughout the upgrade to identify and resolve issues quickly.

Conclusion :-

Following these steps ensures a smooth and reliable upgrade of your AWS EKS cluster with minimal downtime. Regular upgrades help maintain security, stability, and access to the latest Kubernetes features