How to upgrade the version of your EKS cluster created by pltf.

Overview

EKS does not auto-upgrade clusters. Upgrade one minor version at a time (e.g., 1.24 → 1.25). Steps below use the AWS console; CLI works too.

Step 1: Control Plane

1. Open the EKS cluster (correct region).
2. Click Update now on the control plane.
3. Select the next Kubernetes version and start the update.

Important: During control plane upgrade (~20 min) avoid new deploys or kubectl changes. Running workloads keep serving traffic.

Step 2: Node Groups

1. Go to Configuration → Compute.
2. For each managed node group, click Update now.
3. Use Rolling update strategy and start the upgrade.

Important: Nodes are replaced. If ingress is not HA, expect brief downtime while pods reschedule. Upgrade node groups one at a time.

Step 3: Pin versions in specs

After upgrading, pin the new versions so future applies stay consistent:

modules:
  - type: aws_eks
    k8s_version: "1.25"
  - type: aws_nodegroup
    name: default
    k8s_version: "1.25"

pltf terraform plan -f env.yaml -e prod
pltf terraform apply -f env.yaml -e prod

Breaking Changes

• Review Kubernetes API deprecations for your target version.
• Ensure add-ons (CNI, metrics, ingress) are compatible.
• For multi-hop upgrades (e.g., 1.22 → 1.24), step through each minor version.

References

• AWS: https://docs.aws.amazon.com/eks/latest/userguide/update-cluster.html
• Versions: https://docs.aws.amazon.com/eks/latest/userguide/kubernetes-versions.html