Operations performed during a mandatory EKS Cluster version update

We recommend that you proactively update your control plane without relying on the Amazon EKS automatic update process

Document reference - https://docs.aws.amazon.com/eks/latest/userguide/kubernetes-versions.html#version-deprecation

Q: Are Amazon EKS managed node groups automatically updated along with the cluster control plane version?

A: No, a managed node group creates Amazon EC2 instances in your account. These instances aren't automatically upgraded when you or Amazon EKS update your control plane. Assume that Amazon EKS automatically updates your control plane. The Kubernetes version that's on your managed node group might be more than one version earlier than your control plane. Then, assume that a managed node group contains instances that are running a version of Kubernetes that's more than one version earlier than the control plane. The node group has a health issue in the Node groups section of the Compute tab of your cluster in the console. Last, if a node group has an available version update, Update now appears next to the node group in the console. For more information, see Updating a managed node group. We recommend maintaining the same Kubernetes version on your control plane and nodes.

Q: Are self-managed node groups automatically updated along with the cluster control plane version?

A: No, a self-managed node group includes Amazon EC2 instances in your account. These instances aren't automatically upgraded when you or Amazon EKS update the control plane version on your behalf. A self-managed node group doesn't have any indication in the console that it needs updating. You can view the kubelet version installed on a node by selecting the node in the Nodes list on the Overview tab of your cluster to determine which nodes need updating. You must manually update the nodes. For more information, see Self-managed node updates. The Kubernetes project tests compatibility between the control plane and nodes for up to two minor versions. For example, 1.24 nodes continue to operate when orchestrated by a 1.26 control plane. However, running a cluster with nodes that are persistently two minor versions behind the control plane isn't recommended. For more information, see Kubernetes version and version skew support policy in the Kubernetes documentation. We recommend maintaining the same Kubernetes version on your control plane and nodes.