Art of Codeartofcode
Lesson 14 of 15

30. Observability

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The picture to keep in your head
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30.1 Why do you need observability?
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30.2 What are the three pillars?
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30.3 What are golden signals, RED and USE?
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30.4 What are SLI, SLO and SLA?
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30.5 What are error budgets?
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30.6 How do you alert without noise?
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30.7 What makes a good dashboard?
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30.8 How do you debug an incident, step by step?
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Memory card and where the analogy breaks
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Practice: five levels
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Interview questions
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Solutions
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Sources
15
Code lab
30. Observability

Sources

3 min read+10 XP

Source notes

  • Four golden signals and SLI/SLO/SLA definitions: Betsy Beyer et al., Site Reliability Engineering (Google, O'Reilly 2016), chapters "Monitoring Distributed Systems" and "Service Level Objectives".
  • Multiwindow, multi-burn-rate alerting (for example, page at a 14.4× burn over 1 hour, confirmed by a 5-minute window, which spends 2% of a 30-day budget in an hour): The Site Reliability Workbook (Google, O'Reilly 2018), "Alerting on SLOs". Checked 2026-10-08.
  • RED method: Tom Wilkie, "The RED Method" (2018). USE method: Brendan Gregg, "The USE Method".
  • OpenTelemetry (traces, metrics, logs): opentelemetry.io. W3C Trace Context (traceparent): W3C Recommendation.
  • Metric types and label cardinality: Prometheus documentation, "Metric types" and "Instrumentation" best practices.
  • Blameless postmortems: Site Reliability Engineering, "Postmortem Culture: Learning from Failure".
  • Traffic, latency, log-size and checkout figures are illustrative assumptions; arithmetic computed 2026-10-08.
  • Level 3 and Level 4 code: tested 2026-10-08 (code/ch30_observability.py, all checks pass).