Spring Boot Observability

Production observability with Actuator endpoints, Micrometer metrics, and OpenTelemetry tracing.

Core Components

Core Workflow

1. Add starters → actuator, micrometer-registry-*, opentelemetry
2. Configure endpoint exposure → Secure sensitive endpoints
3. Define health groups → Separate liveness from readiness
4. Add custom metrics → Business-specific measurements
5. 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

Critical Reminders

1. Separate liveness from readiness — Liveness: "is process alive?", Readiness: "can handle traffic?"
2. Low cardinality tags only — User IDs, request IDs = bad; status codes, regions = good
3. Secure Actuator endpoints — Use separate port or authentication
4. Sample traces in production — 100% sampling overwhelms collectors
5. Graceful shutdown — Allow in-flight requests to complete