Meta's Service Health Checker is a system that monitors the health of thousands of services in production. It uses templated metric queries and thresholds to detect potential issues before they cause problems. The system also integrates with tiered and phased rollouts to automatically roll back changes that trigger regressions. However, at scale, Meta encountered operational problems such as noise, alert fatigue, drift, and uncovered regressions. To address these issues, the team deployed a program of measurement, tooling, and improved defaults. --- Why it matters: This matters because it shows how large-scale deployment systems can be made safer through proactive monitoring and automated rollback. Engineers working on similar systems can learn from Meta's experience and apply these lessons to their own projects. Source: https://arxiv.org/abs/2608.20513