THE MOST IMPORTANT CONCEPT: MEASURING RELIABILITY: SLO, SLA, SLI

Site Reliability Engineering is not just monitoring or fixing servers. It is: Applying software engineering principles to operations to make systems reliable at scale. That means: You don’t manually fix things → you automate You don’t guess → you measure You don’t react → you design for failure Core mindset A normal engineer asks: “Is the system working?” An SRE asks: “How well is it working, how often does it fail, and how much failure is acceptable?” Before SRE existed, companies said: System