Ensuring Smooth Operations: A Guide to Kubernetes and EKS Upgrades

Upgrading Kubernetes clusters is a critical aspect of maintaining a secure, performant, and future-ready infrastructure. Whether you’re self-hosting Kubernetes or leveraging managed services like Amazon EKS (Elastic Kubernetes Service), the upgrade process needs careful planning to avoid downtime and ensure compatibility across all workloads and components.

This guide covers the key considerations, steps, and best practices for both Kubernetes and EKS upgrades—giving your development and DevOps teams the confidence to keep your clusters running on the latest and most secure versions.

Why Upgrade Kubernetes?

Kubernetes follows a rapid release cycle, with a new minor version approximately every three months. Each version includes:

• Security patches

• API deprecations and improvements

• New features and enhancements

• Performance optimizations

If you lag behind, your cluster may miss important security updates or support for newer tooling. More critically, unsupported versions receive no patches, exposing your workloads to potential vulnerabilities. Additionally, many cloud-native tools and operators depend on specific Kubernetes versions and may not function properly on older releases.

Understanding the Upgrade Path

Kubernetes supports sequential upgrades, meaning you can only jump from one minor version to the next (e.g., from 1.26 to 1.27). Skipping versions is not supported, which makes regular upgrades essential.

You also need to upgrade:

• Cluster control plane components

• Worker nodes and node groups

• Add-ons (CoreDNS, kube-proxy, etc.)

• Custom controllers, CRDs, and integrations

Planning the Upgrade

Before performing a kubernetes upgrade, it’s vital to prepare:

1. Audit Your Cluster

   • Check for deprecated APIs and remove or update them.

   • Ensure your workloads are compatible with the target Kubernetes version.

   • Backup your etcd database and Kubernetes objects.

2. Review Release Notes

   • Understand what’s new, what’s deprecated, and what’s removed.

   • Follow upstream documentation and vendor-specific notes (e.g., Amazon EKS release notes).

3. Test in Staging

   • Clone your production setup to a staging environment.

   • Run tests for all workloads and automation (CI/CD, autoscalers, monitoring).

4. Update the Cluster Infrastructure

   • Update infrastructure-as-code (Terraform, Helm, etc.) to reflect version changes.

   • Ensure autoscalers, ingress controllers, and other add-ons are compatible.

Performing a Kubernetes Upgrade

The upgrade process differs slightly between self-managed Kubernetes and Amazon EKS. Here’s how it works in both environments.

Self-Managed Kubernetes

For clusters hosted on VMs or bare metal (using kubeadm or similar tools), upgrading requires:

1. Control Plane Upgrade

   • Drain and cordon the control plane node.

   • Upgrade kubeadm, kubelet, and kubectl.

   • Apply the new Kubernetes version using kubeadm upgrade.

2. Worker Nodes

   • Drain each worker node one at a time.

   • Upgrade kubelet and Kubernetes binaries.

   • Restart the kubelet and uncordon the node.

3. Post-Upgrade Validation

   • Check node and pod health with kubectl get nodes and kubectl get pods -A.

   • Verify monitoring dashboards and alerting systems are functional.

Amazon EKS Upgrade

With managed Kubernetes in AWS, Amazon handles control plane upgrades, but node upgrades are still your responsibility.

1. Control Plane

   • Go to the EKS console or use the AWS CLI to initiate the upgrade.

   • Amazon will safely update the control plane with minimal disruption.

2. Managed Node Groups

   • Update node groups to use the new AMI for the target Kubernetes version.

   • Use rolling updates to replace old nodes with new ones.

3. Add-ons

   • EKS lets you upgrade critical add-ons like CoreDNS and kube-proxy via the console or CLI.

4. Custom AMI Nodes

   • If you’re using custom AMIs, bake a new image using the updated version and redeploy the node group.

In the middle of your upgrade strategy, you must pay special attention to the kubernetes upgrade, eks upgrade compatibility matrix. Make sure your cloud-native tools (such as ArgoCD, Prometheus, and external DNS) support the new version you’re migrating to.

Best Practices for Kubernetes and EKS Upgrades

• Automate: Use infrastructure-as-code to handle upgrades in a consistent, repeatable way.

• Monitor During Upgrade: Observe metrics and logs to detect anomalies early.

• Limit Changes: Don’t combine a Kubernetes upgrade with other changes (e.g., application deployments).

• Notify Stakeholders: Coordinate with teams to minimize disruptions.

• Roll Back Plan: Always prepare a rollback strategy—snapshots, backups, and blue-green deployment models can help.

Common Pitfalls to Avoid

1. Ignoring Deprecation Warnings

   • Deprecated APIs may break your workloads after an upgrade.

2. Skipping Node Upgrades

   • Running mismatched control plane and worker versions can introduce instability.

3. Missing Add-on Updates

   • Tools like CoreDNS or kube-proxy may not function properly if not updated post-upgrade.

4. Lack of Testing

   • Skipping tests on staging environments can lead to post-upgrade surprises.

Final Thoughts

Regular kubernetes upgrade and eks upgrade processes are not just technical maintenance—they are a crucial part of your DevOps maturity. Staying current ensures your workloads are secure, your performance is optimized, and your infrastructure is ready for modern development practices.

By approaching upgrades methodically—auditing your resources, testing carefully, and automating where possible—you’ll minimize risk and gain the full benefits of each new release.

Keep your clusters fresh, safe, and scalable. The effort you invest in upgrades pays dividends in stability and confidence.