Design a release system for 400 services and 60 teams
An organisation runs 400 services owned by 60 teams across four regions. Releases are currently coordinated in a weekly meeting with a spreadsheet. A single service's bad release last month caused a cross-service outage because a change to a shared message format was deployed before its consumers could handle it. Design the release system.
The fix that looks right
Replacing the weekly meeting with a central release-orchestration system that sequences all deployments organisation-wide, so shared-contract changes are always ordered correctly. It solves the stated problem and creates a worse one: every team's delivery now depends on a single system's availability and on a global ordering, so 400 services are serialised behind one queue, an incident in the orchestrator blocks all deployment including the fix for the incident, and the coupling the design was meant to remove has been made structural instead of incidental. Coordination that works at 400 services is compatibility enforced locally, not sequencing enforced centrally.