Upgrade EKS Nodes with Karpenter: A Complete Guide (2026)

As organizations increasingly adopt Kubernetes for managing their applications, AWS Elastic Kubernetes Service (EKS) has become a popular choice due to its robustness and integration with AWS services. The introduction of Karpenter, an open-source project that helps automatically provision and scale nodes in Kubernetes clusters, offers a promising alternative to AWS Managed Node Groups. However, upgrading the version of EKS nodes managed by Karpenter can seem daunting. This guide will walk you through the process step-by-step, ensuring that your node upgrades are smooth and efficient.

Key Takeaways

• Understand how Karpenter simplifies scaling in EKS.
• Learn to upgrade EKS nodes using Karpenter effectively.
• Discover how to leverage AWS CLI for node management.
• Explore troubleshooting common upgrade issues.
• Gain insights into maintaining cluster performance during upgrades.

Introduction

Karpenter enhances the way we manage Kubernetes nodes by dynamically provisioning the right compute resources based on the cluster's needs. This is particularly useful for teams looking for a more flexible and automated approach than AWS Managed Node Groups. However, one common challenge is upgrading these nodes to newer versions, which is crucial for maintaining security, performance, and access to new features.

This tutorial will guide you through upgrading EKS nodes managed by Karpenter, ensuring your cluster remains up-to-date and performant.

Prerequisites

• An existing EKS cluster with Karpenter configured.
• Basic knowledge of AWS CLI and Kubernetes.
• Access to AWS Management Console.
• kubectl installed and configured for your cluster.

Step 1: Assess Current EKS and Node Versions

Before starting the upgrade, it's crucial to understand the current state of your EKS cluster and the versions of the nodes you're running. You can check your EKS version using:

aws eks describe-cluster --name your-cluster-name --query 'cluster.version' --output text

To list the node versions, use:

kubectl get nodes -o wide

Step 2: Plan Your Upgrade

Review the AWS EKS release notes to determine if there are any considerations or additional steps needed for the upgrade. Planning helps avoid unexpected downtimes.

Step 3: Update Karpenter Configuration

Update your Karpenter configuration to support the new node version. This might involve changing the AMI ID to one that supports the new version:

apiVersion: karpenter.sh/v1alpha5
kind: Provisioner
spec:
  requirements:
    - key: "kubernetes.io/arch"
      operator: "In"
      values: ["amd64"]
  provider:
    amiFamily: "AL2" # Amazon Linux 2
    amiID: "ami-xyz123" # Update this to the latest AMI for your region

Step 4: Scale Down Old Nodes

Begin by scaling down the existing nodes. This can be done manually or automatically using Karpenter. To manually cordon and drain a node, use:

kubectl cordon 
kubectl drain  --ignore-daemonsets

Step 5: Deploy New Nodes

Once the old nodes are cordoned and drained, Karpenter will provision new nodes with the updated configuration. Monitor the nodes to ensure they are added successfully:

kubectl get nodes -o wide

Verify that the new nodes are running the desired Kubernetes version.

Step 6: Validate the Upgrade

After the new nodes are running, validate the stability and performance of your cluster. Run workloads and observe resource utilization. Also, ensure that your applications are functioning as expected.

Common Errors/Troubleshooting

If you encounter issues during the upgrade, consider the following:

• Ensure your IAM policies allow Karpenter to provision resources.
• Check for incompatible AMI IDs or missing permissions.
• Review logs for any provisioning errors using AWS CloudWatch.

Frequently Asked Questions

Why should I use Karpenter over AWS Managed Node Groups?

Karpenter offers more automation and flexibility, particularly useful for dynamic workloads.

How often should I upgrade my EKS nodes?

Regular upgrades are recommended, ideally every few months, to ensure security and performance.

What if a node fails to provision during an upgrade?

Check IAM permissions and Karpenter logs for errors, and ensure AMI compatibility.

Frequently Asked Questions

Why should I use Karpenter over AWS Managed Node Groups?

Karpenter offers more automation and flexibility, particularly useful for dynamic workloads.

How often should I upgrade my EKS nodes?

Regular upgrades are recommended, ideally every few months, to ensure security and performance.

What if a node fails to provision during an upgrade?

Check IAM permissions and Karpenter logs for errors, and ensure AMI compatibility.