In the world of technology, three roles have shaped how systems are built, run, and kept alive: the traditional System Administrator, the modern DevOps engineer, and the specialized Site Reliability Engineer. Each emerged from different needs, shaped by the tools and challenges of their time. As businesses shifted from on-premises hardware to cloud-native architectures, these roles adapted, overlapped, and sometimes evolved into one another. This is the story of their journey—where they came from, how they’ve changed, and where they stand today.