Cloud bills often show total spend per service — but that view is too broad to drive real optimization. In the Frugal Architect webinar, AWS Senior Solutions Architect Nataliya Godunok highlighted a critical but often overlooked feature:
Split Cost Allocation for Amazon EKS.
When activated, it lets you break down spend by namespace, workload, or even team, using Kubernetes tags. As Nataliya puts it:
“Monthly cost by service or account doesn’t always translate to meaningful business insights.” - Nataliya Godunok, AWS Senior Solutions Architect
The Problem: You can’t fix what you can’t see
Imagine trying to cut costs when all you see is:
EKS: $4,332.82
That number tells you nothing about:
- Which team’s workload used the most resources
- Whether a spike was caused by a specific app
- How much each namespace contributes to the bill
The Frugal Architect philosophy reminds us:
“Unobserved systems lead to unknown costs.”— Law IV, from the 7 Laws of the Frugal Architect
The Solution: Split Cost Allocation for EKS
AWS now lets you break down your EKS costs using split allocation tags — giving you clear cost visibility by workload or label. You just need to tag your workloads properly, and AWS will do the rest.
Here’s how it looks in practice:
It answers questions like:
- Which workloads are most expensive?
- Which namespaces or node groups are underused?
- Are we spending efficiently across teams?
And a deeper dive into use cases:
How to Implement Split Cost Allocation for EKS
1. Enable Cost Allocation Tags
Go to AWS Billing > Cost Allocation Tags. Turn on relevant Kubernetes tags like:
kubernetes.io/cluster/
eks:nodegroup-name
Custom: app, team, etc.
2. Apply Tags to Your EKS Resources
Use labels in your pod specs or Helm charts:
metadata:
labels:
app: payment-service
team: backend
3. Use AWS Cost Explorer or CUR
Analyze usage in AWS Cost Explorer or via the Cost & Usage Report (CUR) for deep insights.
›› Take a look at AWS Cost and Usage Report (CUR) with PerfectScale
Common Pitfalls with Split Cost Allocation for EKS
“Granular visibility requires intentional tagging. It won’t work by accident.” - Nataliya Godunok, AWS Senior Solutions Architect
Watch out for:
- Untagged pods — these get lumped into "unallocated"
- Inconsistent tags — make comparison difficult
- Slow data refresh — some tools update only daily
Success Metrics to Track
Tips from the Experts
- Use automation tools like Terraform or ArgoCD to enforce tagging.
- Combine Split Cost Allocation with AWS Budgets and Cost Anomaly Detection to catch unexpected changes fast.
- Review your cost data monthly — not just during incident reviews.
Recap
Split Cost Allocation isn’t just a tool — it’s a mindset shift. It helps transform cloud cost from an end-of-month shock into an engineering signal.
Useful Resources
- AWS: Improve cost visibility of EKS
- Well-Architected Container Lens
- FinOps Introduction
- The Frugal Architect
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