Observability
Implement the three pillars of observability: logs, metrics, and traces.
The Three Pillars
| Pillar | Purpose | Key Question |
|---|---|---|
| Logs | Discrete events with context | What happened? |
| Metrics | Aggregated measurements | How much/many? |
| Traces | Request flow across services | Where did time go? |
Quick Pick
- Debug specific request? → Logs + Traces
- Alert on thresholds? → Metrics
- Understand system health? → All three
- Starting from zero? → Logs first, then metrics, then traces
Key Principles
- Use structured logging (JSON) with correlation IDs across all services
- Instrument the four golden signals: latency, traffic, errors, saturation
- Define SLIs/SLOs before building dashboards or alerts
- Alert on symptoms (user impact), not causes (CPU usage)
Quick Start Checklist
- Set up structured logger (Pino recommended for Node.js)
- Add request correlation IDs (middleware)
- Instrument key metrics (RED: Rate, Errors, Duration)
- Configure distributed tracing (OpenTelemetry)
- Create dashboards for golden signals
- Set up alerts with appropriate severity levels
References
| Reference | Description |
|---|---|
| logging-patterns.md | Structured logging, log levels, Pino/Winston setup |
| metrics-guide.md | Prometheus, counters/gauges/histograms, golden signals |
| tracing-basics.md | OpenTelemetry, distributed tracing, span design |
| alerting-guide.md | Alert design, SLIs/SLOs, severity levels, dashboards |