DEV Community: Jack HB

Supercharging EKS Autoscaling: Moving Beyond Cluster Autoscaler with Karpenter

Jack HB — Tue, 08 Sep 2026 06:04:38 +0000

Hey cloud and DevOps community,

In my previous post, I shared how we cut our EKS cluster costs by 35%. One of the absolute biggest game-changers in achieving that milestone was replacing the traditional Cluster Autoscaler with Karpenter.

If you're still waiting 3 to 5 minutes for EC2 nodes to spin up when your Kubernetes pods are in a Pending state, you're bleeding money and hurting application responsiveness.

Here is a quick look at why we made the switch and how it transformed our infrastructure:

1. The Problem with Legacy Autoscaling

Slow Node Provisioning: Standard Cluster Autoscaler relies on AWS Auto Scaling Groups (ASGs), which introduces heavy latency during scale-out events.
Rigid Instance Types: Managing various instance types and Spot instances requires complex node groups and constant maintenance.

2. Why Karpenter Changes the Game

Sub-second Provisioning: Karpenter provisions right-sized compute resources directly within seconds, matching application load dynamically.
Consolidated Scheduling: It automatically packs pods tightly onto nodes, maximizing bin-packing efficiency and slashing idle waste.

3. Practical Example: A Simple Karpenter Provisioner Config

Here is a lightweight example of how we define a provisioner to handle multi-instance flexibility and spot interruption handling:

apiVersion: karpenter.sh/v1alpha5
kind: Provisioner
metadata:
  name: default
spec:
  requirements:
    - key: "karpenter.sh/capacity-type"
      operator: In
      values: ["spot", "on-demand"]
    - key: "node.kubernetes.io/instance-type"
      operator: In
      values: ["t3.medium", "t3.large", "m5.large"]
  limits:
    resources:
      cpu: 1000
  providerRef:
    name: default-node-template
  ttlSecondsAfterEmpty: 30

4. The Results

By letting Karpenter handle node lifecycle management natively, we reduced our peak scale-out latency by over 80% and optimized our spot instance blend seamlessly.

You can dive deeper into our architectural configurations and deployment steps on my archive:

👉 https://jackhb1970.blogspot.com/

How has your experience been with Karpenter versus traditional ASGs? Drop your thoughts or architecture tips in the comments below!

Cheers,

Jack_Insight

How I cut our EKS cluster costs by 35% using FinOps patterns

Jack HB — Tue, 08 Sep 2026 05:59:34 +0000

Hey devops and cloud engineering community,

I’ve been knee-deep in a massive cloud migration and Kubernetes optimization project lately, and frankly, our EKS bill almost gave me a heart alarm last month.

Like many of you might be experiencing, our costs were ballooning due to two silent killers:

Idle Resources: Clusters running full throttle at 3 AM with zero traffic.
Over-provisioning: Pods sized for peak traffic, but running on a regular weekday.

After a lot of trial and error, wrestling with Karpenter, and fine-tuning HPA/VPA, we managed to claw back 35% of our monthly EKS spend without sacrificing performance.

I documented the entire journey, the specific architectural patterns we implemented (moving beyond just "turn it off at night"), and a practical audit checklist you can run against your own clusters.

You can find the detailed technical breakdown and code snippets on my archive here:

👉 ** https://jackhb1970.blogspot.com/ **

I’m curious to hear how you guys are tackling EKS FinOps in your environments. What tools or strategies are working (or failing) for you? Let’s discuss in the comments.

Cheers,
Jack_Insight

How I cut our EKS cluster costs by 35% using FinOps patterns

Jack HB — Tue, 08 Sep 2026 02:59:29 +0000