Kubernetes & EKS Upgrade Guide: Strategies, Best Practices, and Pitfalls to Avoid

Upgrading Kubernetes—whether self-managed or through a managed service like Amazon EKS (Elastic Kubernetes Service)—is a critical part of maintaining a secure, efficient, and performant containerized infrastructure. However, it's also a process that requires careful planning, validation, and execution to avoid disruptions.

This article provides a comprehensive overview of Kubernetes and EKS upgrades, highlighting why they matter, what challenges organizations face, and best practices for smooth transitions.

Why Kubernetes Upgrades Matter

Kubernetes evolves rapidly, with three major releases each year. Each version includes critical security patches, performance improvements, new features, and the deprecation of outdated APIs. Running outdated versions can expose clusters to vulnerabilities, compatibility issues, and missed opportunities for operational improvements.

Here’s why staying current with Kubernetes versions is important:

• Security: Vulnerabilities are fixed in newer versions, and older versions eventually reach end-of-life (EOL), no longer receiving patches.

• Compatibility: Third-party tools and cloud services often align with recent Kubernetes versions.

• New Features: Upgrades introduce capabilities that improve scaling, observability, automation, and workload management.

• Supportability: Cloud providers like AWS only support specific versions for EKS, meaning outdated clusters may no longer receive full support.

Understanding Kubernetes Upgrade Challenges

Despite the benefits, upgrading Kubernetes is not a trivial task. Each version may deprecate APIs, require changes in configurations, or impact running workloads. Common challenges include:

• API Deprecations: Old APIs may be removed, breaking applications that depend on them.

• Compatibility Testing: Helm charts, operators, and CRDs must be tested for version compatibility.

• Downtime Risks: Poor planning can result in service interruptions or degraded performance.

• Infrastructure Drift: Manually managed clusters may drift from desired state, making upgrades complex.

• Dependency Chaos: Upgrades often reveal issues in underlying container runtimes, storage classes, or ingress controllers.

These challenges emphasize the need for a controlled, step-by-step upgrade process.

The EKS Upgrade Process: What Makes It Unique

Amazon EKS simplifies some parts of Kubernetes lifecycle management by managing the control plane for users. However, EKS upgrades still require attention and preparation. Here's what makes upgrading EKS different:

1. Managed Control Plane

AWS handles the control plane upgrade, reducing complexity and operational burden. Users initiate the process, and AWS manages the API server and related services.

2. Node Group Responsibility

While AWS upgrades the control plane, users must upgrade their worker nodes—whether managed node groups, self-managed EC2 nodes, or Fargate profiles.

3. Version Availability

EKS does not support all Kubernetes versions immediately. AWS typically lags behind upstream Kubernetes releases to ensure stability and integration.

4. API Deprecation Notices

EKS provides detailed version documentation, listing deprecated APIs and breaking changes relevant to the upgrade path.

5. Add-ons and Custom Resources

Users need to update EKS add-ons (e.g., CoreDNS, kube-proxy, VPC CNI) and any custom controllers or CRDs that may be impacted by the new version.

Best Practices for Kubernetes and EKS Upgrades

Whether managing Kubernetes yourself or via EKS, following best practices helps reduce risk and ensure a seamless upgrade process.

1. Read the Release Notes Thoroughly

Understand what’s changing between the current and target versions. Pay attention to deprecations, removals, and behavioral changes.

2. Test in Staging First

Always run upgrades in a staging or non-production environment to validate workloads, integrations, and configurations.

3. Upgrade Incrementally

Avoid skipping multiple versions at once. Kubernetes only supports direct upgrades between minor versions (e.g., 1.25 to 1.26). For EKS, this means upgrading one version at a time.

4. Audit and Update APIs

Use tools like kubectl or third-party scanners to detect deprecated APIs and update manifests accordingly.

5. Backup Before You Begin

Ensure you have recent backups of configurations, secrets, and persistent volumes (if applicable) before starting the upgrade.

6. Plan for Node Drainage and Recreation

When upgrading EKS node groups, follow a rolling replacement strategy:

• Create a new node group with the target version

• Drain workloads from old nodes

• Delete the old group after validation

This minimizes downtime and ensures continuity.

7. Update Add-ons and Dependencies

Don't forget to upgrade Kubernetes add-ons and ensure compatibility with your ingress controller, service mesh, monitoring tools, and storage classes.

8. Automate Where Possible

Use infrastructure as code (IaC) tools like Terraform or CDK for reproducibility. Managed tools like AWS Blueprints or EKSctl can also assist in automating parts of the upgrade process.

9. Monitor After Upgrade

Post-upgrade, closely monitor cluster health, application logs, and metrics to quickly catch and resolve regressions.

EKS Upgrade Lifecycle Considerations

AWS typically supports the three latest Kubernetes versions. Once a version reaches EOL (usually after 14 months), it's deprecated and eventually removed from EKS support. Organizations should:

• Keep an upgrade calendar aligned with EKS announcements

• Subscribe to AWS newsletters or status updates

• Regularly allocate time and resources for upgrades as part of DevOps cycles

Failing to upgrade in time can lead to forced migrations, support issues, and operational risks.

Conclusion

Kubernetes and EKS upgrades are more than technical chores—they are strategic operations that ensure long-term scalability, security, and innovation. By treating upgrades as routine and integrating them into your DevOps lifecycle, your team can stay ahead of potential issues and harness the full power of cloud-native infrastructure.

Organizations that adopt proactive upgrade practices not only improve resilience but also gain access to cutting-edge features that unlock faster delivery and greater control over their environments.

If you're running Kubernetes—whether self-managed or on EKS—start planning your next upgrade today. Your future workloads will thank you.