97 Things Every SRE Should Know

Chapter 1. Site Reliability Engineering in Six Words

Alex Hidalgo

Nobl9

When someone I’ve just met asks me what I do for a living, I generally fall back to something along the lines of, “I’m a site reliability engineer. We keep large-scale computer services reliable.” For many people, this is sufficiently boring and our general pleasantries continue. Occasionally, though, I run into people who are a bit more curious than that: “Oh, that sounds interesting! How do you do that?”

That’s a difficult question to answer! What do SREs actually do? For many years, I’d rely on just listing an assortment of things—some of which have made their way into essays in this very book. Although an answer like that wasn’t exactly wrong, it also never felt truly satisfying. There had to be a more cohesive answer, and when I reflect on my decade of performing this job, I think I’ve finally figured it out. Virtually everything SREs do relies on our ability to do six things: measure, analyze, decide, act, reflect, and repeat.

Measuring does not just mean collecting data. To measure something, you have some sort of goal in mind. You don’t collect flour to bake a cake, you measure the flour; otherwise, things will end up a mess. SREs need to measure things because pure data isn’t enough. Our data needs to be meaningful. We need to be able to answer the question, “Is this service doing what its users need ...