What Makes Your EKS Cluster Idle, And What You Can Do

EKS clusters are easy to use, but can be challenging to manage effectively.

Many teams unknowingly let their EKS clusters run idle. These clusters consume compute power, keep nodes active, and incur costs without producing any useful results.

The Silent Burn: What Is an Idle Cluster?
An idle EKS cluster has running pods, but:

• No real workloads are being offered.
• No external traffic is reaching it.
• No CI/CD jobs are in progress.
• Developers aren’t using it, but EC2 nodes are still running.

Essentially, you're paying for infrastructure that is just sitting still.

Common Scenarios for Idle Clusters

1. Development/Test Clusters up overnight
   Environments get created during the day, and hang around awake overnight and over weekends.

2. Burst Workloads but doesn't scale down
   A job runs once, and the node groups remain scaled up long after.

3. Unattached Services/Orphaned Deployments
   Pods are running, but no services are connected to them. They can remain idle and accrue costs.

4. Monitoring or logging agents may keep the nodes awake
   Even lightweight agents could keep you from autoscaling down to 0.

How Do You Know if Your Cluster is Idle?
Some quick checks to do:

kubectl top nodes
kubectl top pods-- all-namespaces

If CPU and memory levels are consistently low, and there aren't pending requests, you are likely idle.

You could also use AWS CloudWatch, or Prometheus/Grafana to monitor:

• Incoming requests
• Network throughput
• Pod activity patterns

Solutions That Don’t Require a Full Re-Architecture
Enable Cluster Autoscaler
It scales down unused nodes based on pod activity. Set it up with the right IAM policies and flags.

Try Karpenter
AWS’s open-source alternative to Cluster Autoscaler. It provides nodes based on pod specifications, helping to eliminate long-running idle nodes.

Use Schedule-Based Shutdowns
Use cron jobs or AWS Lambda to stop/start node groups or even delete test clusters during off-hours.

Improve tagging and labeling hygiene
Use consistent labels to ensure tracking ownership. It also helps with identifying unused deployments that may need to be removed.

Reminder on cost visibility
Manually searching for idle clusters is doable, but note this doesn't scale well when working across multiple accounts, clusters, or teams.

As the footprints of enterprises on the cloud get bigger, it does not make sense to depend only on manual reviews or scattered dashboards for managing and optimizing the environment. That is mostly because, with feature shipping as the main concern, the engineers rarely bother about cleaning up those forgotten clusters.

Hence comes the centralized approach. Equipment that exposes idle clusters, orphan pods, and over-provisioned workloads can empower platform and DevOps teams to ask: 'Shall we act now, or will our delivery be crippled?'

Even more so, tagging and cost allocation become a must if your EKS use spans across many AWS accounts or environments, like dev, test, prod; otherwise, finance and engineering spend each month guessing when that cloud bill drops.

Platforms like Amnic that offer precise cost allocation, idle cluster detection, and actionable insights that work in your existing AWS infrastructure without the need for a new agent or re-engineering.

You can set budgets, trigger alerts based on environment usage exceeding expected use, or drill down into particular services that are silently eating heartily into your wallets.

Bottom Line

• Idle EKS clusters are more common than we think.

• A cluster that does nothing still costs you real money.

• Tools like Cluster Autoscaler, Karpenter, and cost dashboards can help.

• Visibility is key to spotting waste early and fixing it quickly.

Are you currently running an idle cluster? Or have you ever found one too late? Let’s talk in the comments.

Confused about which container orchestration to choose for your workloads? Here’s a quick rundown of ECS vs EKS that may be able to help you with the decision.