49% Cost Reduction on a Large EKS Cluster: Clearing Infrastructure Debt by Decommissioning V1 and Rebuilding V2

~$3,240/month, ~$38,880/year saved (~49%). Consolidated EKS 1.32/1.33 to 1.35, ArgoCD v1 to v3, and Kafka Zookeeper to KRaft in one shot while reducing nodes from 25 to 15. Achieved fully zero-downtime cutover with Route53 Weighted Routing.

April 23, 2026 · 13 min · Hoon Jo