AWS EKS Cost Optimization: Karpenter & Spot Instance Autoscaling

As Kubernetes clusters scale in production, cloud compute infrastructure quickly becomes one of the largest operational expenses for engineering organizations. Traditional Kubernetes Cluster Autoscaler (CA) relies on static AWS Auto Scaling Groups (ASGs), causing slow provisioning delays and inefficient instance sizing.

**TL;DR:** Replace fixed ASGs with Karpenter just-in-time provisioning and AWS Spot Instances to lower Amazon EKS compute costs by up to 60% while speeding up pod scheduling latency.

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1. Karpenter NodePool Manifest Blueprint

apiVersion: karpenter.sh/v1beta1
kind: NodePool
metadata:
  name: spot-cost-optimized
spec:
  template:
    spec:
      requirements:
        - key: "karpenter.sh/capacity-type"
          operator: In
          values: ["spot"]
        - key: "kubernetes.io/arch"
          operator: In
          values: ["arm64", "amd64"]
        - key: "karpenter.k8s.aws/instance-category"
          operator: In
          values: ["c", "m", "r"]
      nodeClassRef:
        name: default
  limits:
    cpu: "1000"
  disruption:
    consolidationPolicy: WhenUnderutilized
    expireAfter: 720h

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2. Cost Optimization Metrics Matrix