majiayu000 Spring Boot Observability
Production observability with Actuator endpoints, Micrometer metrics, and OpenTelemetry tracing.
Core Components
| Component | Purpose |
|---|---|
| Actuator | Health checks, info, metrics exposure, operational endpoints |
| Micrometer | Metrics abstraction (Timer, Counter, Gauge, DistributionSummary) |
| OpenTelemetry | Distributed tracing (default in Spring Boot 4) |
Core Workflow
- Add starters →
actuator,micrometer-registry-*,opentelemetry - Configure endpoint exposure → Secure sensitive endpoints
- Define health groups → Separate liveness from readiness
- Add custom metrics → Business-specific measurements
- Configure tracing → Sampling, propagation, export
Quick Patterns
See EXAMPLES.md for complete working examples including:
- Production Actuator Configuration with health groups and Kubernetes probes
- Custom Health Indicator with latency monitoring (Java + Kotlin)
- Custom Micrometer Metrics with Counter, Timer, and Gauge patterns
- OpenTelemetry Span Customization with Observation API
- OpenTelemetry Configuration for OTLP export
- Actuator Endpoint Access Control (Boot 4)
Spring Boot 4 Specifics
- OpenTelemetry is the default tracer (replaces Brave)
- Health Indicator imports from
org.springframework.boot.health.contributor.* - Endpoint Access Control with
access: none/unrestricted/read-only
Detailed References
- Examples: See EXAMPLES.md for complete working code examples
- Troubleshooting: See TROUBLESHOOTING.md for common issues and Boot 4 migration
- Actuator Endpoints: See references/ACTUATOR.md for endpoint configuration, security, custom endpoints
- Micrometer Metrics: See references/METRICS.md for Timer, Counter, Gauge, DistributionSummary patterns
- Distributed Tracing: See references/TRACING.md for OpenTelemetry, span customization, context propagation
Anti-Pattern Checklist
| Anti-Pattern | Fix |
|---|---|
| DB checks in liveness probe | Move to readiness group only |
| 100% trace sampling in production | Use 10% or less |
| Exposing all endpoints publicly | Separate management port + auth |
| High-cardinality metric tags | Use low-cardinality tags only |
| Missing graceful shutdown | Add server.shutdown=graceful |
| No health probe groups | Separate liveness and readiness |
Critical Reminders
- Separate liveness from readiness — Liveness: "is process alive?", Readiness: "can handle traffic?"
- Low cardinality tags only — User IDs, request IDs = bad; status codes, regions = good
- Secure Actuator endpoints — Use separate port or authentication
- Sample traces in production — 100% sampling overwhelms collectors
- Graceful shutdown — Allow in-flight requests to complete