Scaling with safety: Cloudflare's approach to global service health metrics and software releases

This post introduces Health Mediated Deployments (HMD), a data-driven system for automating software releases across Cloudflare's global network. HMD leverages Prometheus metrics queried via Thanos and Service Level Objectives (SLOs) to monitor service health in real-time, automatically reverting problematic code changes. It also details optimizations for scaling this system, including the use of recording rules and distributed query processing, and its use of R2 for historical data storage and backtesting to ensure rapid response to potential issues.