EKS Cluster Migration — CloudFormation → Terraform
Migrated a team's live EKS cluster from a hand-created CloudFormation stack to Terraform with no meaningful downtime. Ran both clusters in parallel while validating networking, IAM, Kubernetes RBAC, ingress, monitoring, and CI/CD, then cut over application by application. Modernized to an IPv6-primary design with worker nodes in private subnets, removing per-node public IPv4s and the associated public-networking cost (verified before/after in AWS Cost Explorer).