Observability and SRE: Logs, Metrics, Traces and Reliability

Contents

Every lesson has the same steps: what it is, how it works, a real example, common mistakes, then interview questions with answers you can say out loud.

1. Lesson 00What Observability Is and the Three PillarsMonitoring versus observability, logs, metrics and traces, the questions each answers, and the golden signals.12 min
2. Lesson 01Logging That Helps: Structured Logs, Levels and Correlation IDsStructured JSON logs, levels, what to log and not log, correlation IDs across services, and sampling.14 min
3. Lesson 02Metrics and Prometheus: Counters, Gauges, Histograms and PercentilesThe metric types, labels and cardinality, why averages lie, percentiles, and a real Prometheus scrape of a Node service.15 min
4. Lesson 03Distributed Tracing With OpenTelemetrySpans and traces, context propagation, instrumenting a Node service, and reading a trace to find a slow call.15 min
5. Lesson 04SLIs, SLOs and Error BudgetsChoosing indicators, setting objectives, how nines translate to minutes, burn rates and what error budgets are for.14 min
6. Lesson 05Alerting and Dashboards That People TrustAlerting on symptoms, avoiding alert fatigue, runbooks, dashboard design, and burn-rate alerts with a worked example.13 min
7. Lesson 06Incidents, On-Call and Blameless Post-MortemsIncident roles and the first hour, communication, on-call habits, writing a blameless post-mortem with a full example.14 min
8. Lesson 07Reliability Patterns: Timeouts, Retries, Circuit Breakers and Graceful DegradationFailure modes, timeouts and retries with backoff, circuit breakers, bulkheads, load shedding, tested with fault injection.15 min
9. Lesson 08Observability and SRE Interview Questions With Model AnswersQuestions on monitoring, SLOs, incidents and reliability with model answers.14 min