Upgrading EKS Cluster kubernetes version

• Verify the cluster's subnets have at least 5 available addresses. EKS will launch new nodes for the control plane. A rolling update is done.
• Resolve any issues in EKS upgrade insights.
• Ensure the worker nodes are running the same kubernetes version as the control plane.
• Upgrade the control plane to the next minor version (for example, from 1.32 to 1.33). You can update only one minor version at a time. This can be done in the console.
• Upgrade the nodes in the data plane to match that of the control plane.Starting 1.28 and above, EKS managed node groups support 3 minor version skew betweeen control plane and data plane. For example, if your EKS control plane version is 1.28, you can safely use kubelet versions as old as 1.25. A node's kubelet can't be newer than kube-apiserver.
• Upgrade any additional applications that run on the cluster (for example, cluster-autoscaler). Update the Cluster Autoscaler to the latest version that matches the Kubernetes major and minor version that you updated to. For example, if your cluster’s Kubernetes version is 1.30 find the latest Cluster Autoscaler release that begins with 1.30.
• Upgrade EKS addons. This can be triggered with a terraform apply.
• Upgrade any clients that communicate with the cluster, for example, kubectl. Typically, kubectl is expected to be within one minor version difference (either newer or older) of the kube-apiserver.

References

• https://docs.aws.amazon.com/eks/latest/userguide/update-cluster.html
• https://docs.aws.amazon.com/eks/latest/best-practices/cluster-upgrades.html
• https://repost.aws/knowledge-center/eks-plan-upgrade-cluster