Google SRE's Evolution: From Error Budgets to Systems Theory

Google's Site Reliability Engineering (SRE) team has undergone a significant evolution over the past 25 years. Initially relying on methods like Service Level Objectives (SLOs), error budgets, and isolation strategies, Google's SRE team has shifted towards systems theory and control theory, adopting the STAMP framework to address increasingly complex systems and emerging challenges. STAMP shifts the focus from preventing individual component failures to understanding and managing complex system interactions. This article uses a real-world case study to illustrate how STAMP helps Google prevent system-level failures and explores its future applications across the tech industry.