Lesson 222
Observability & SRE
metrics · traces · SLOs · error budgets
1:00How Site Reliability Engineering uses metrics, logs, traces, SLOs, and error budgets to keep production systems measurably reliable without sacrificing development velocity.
By the end, you can
- Distinguish monitoring from observability and explain when each is insufficient on its own.
- Name the three pillars of observability and describe the cost/benefit trade-offs of each.
- Read a trace waterfall and identify the bottleneck span.
- List the four golden signals and explain the alerting rule that prevents alert fatigue.
- Define SLI, SLO, and SLA and explain why the SLO must be stricter than the SLA.
- Calculate an error budget from an SLO and convert it to minutes of allowed downtime.
- Explain the "ship vs freeze" decision driven by error budget health.
- Compare the downtime implications of 99%, 99.9%, 99.99%, and 99.999% availability targets.
- Define toil and state the SRE cap on how much toil is acceptable.
- Describe the purpose of a blameless postmortem and distinguish it from blame-oriented incident reviews.
- Trace the four-step SRE loop (Observe → Define → Spend → Learn) and explain how it connects all the above concepts.
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