ADR-0001 — EC2 over MWAA for Airflow deployment

Status: accepted Date: 2026-05-31

Context

AWS Managed Airflow (MWAA) costs ~350$/month regardless of usage — even when the environment is idle. For intermittent or experimental workloads, this is not viable.

Decision

Airflow runs on an EC2 t3.small (~15$/month when running, ~1$/month EBS at rest). The instance is started/stopped on schedule via EventBridge + Lambda. An Elastic IP is assigned to keep a stable address across restarts.

Sizing: t3.small (2 vCPU, 2 GiB) for Airflow alone; t3.medium if colocated with other services.

Consequences

Cost: 0–15$/month vs ~350$/month. Trade-off: manual setup, no managed upgrades. Acceptable for a one-person team. MWAA should be reconsidered if the workload requires HA or multi-tenant access.