AWS ECS Fargate Cost Allocation: Why Your Per-Cluster Spend Shows as One Line

TL;DR — Activating aws:ecs:clusterName and aws:ecs:serviceName in Cost Allocation Tags is not enough to get per-cluster Fargate visibility. You also need Split Cost Allocation Data (SCAD) for ECS enabled in the payer account. Without it, 100% of your Fargate spend lands in the empty-tag bucket. Five steps below.

We run a multi-tenant SaaS on AWS. Nine ECS Fargate clusters across two regions. Each cluster maps roughly to a tenant — tenant-a-live, tenant-b-live, tenant-c-live, and so on. About $29,000/month goes to ECS Fargate.

Last week the CTO asked a reasonable question:

"What's the cost per tenant?"

Sure. Open Cost Explorer. Group by service. One line: