Karpenter v1: Smart Kubernetes Node Autoscaling Guide

Cluster Autoscaler served Kubernetes well for almost a decade, but the way it works — add a node by scaling an Auto Scaling Group with a fixed instance type — has been showing its age for years. Karpenter takes a different bet: forget Node Groups, forget pre-baked instance types, and instead let the autoscaler look at pending pods and pick the right EC2 instance in real time. In November 2024, AWS shipped Karpenter v1.0, and by 2026 it has become the default node autoscaler on EKS. Salesforce migrated more than 1,000 EKS clusters to it in production. If you run Kubernetes on AWS and have not moved yet, this guide gets you to a working v1 setup with NodePools, EC2NodeClasses, Spot, and consolidation.

This is a hands-on production guide, not a marketing tour. We will install Karpenter on an existing EKS cluster, configure a NodePool that mixes Spot and On-Demand, watch consolidation kick in, wire up Spot interruption handling through SQS and EventBridge, and walk through the gotchas that bite teams when they roll Karpenter to production. Estimated time: 30–45 minutes if your cluster is already up.