Spring Boot Observability: Metrics, Traces, Logs
Metrics Use Micrometer + Prometheus: management.endpoints.web.exposure.include=prometheus,health,info. Add JVM+Tomcat/db pool meters; set percentiles for latencies. Create SLIs: request latency, error rate, saturation (threads/connections), GC pauses. Traces Spring Boot 3 ships with OTel starter: add spring-boot-starter-actuator + micrometer-tracing-bridge-otel + exporter (OTLP/Zipkin/Jaeger). Propagate headers (traceparent); ensure async executors use ContextPropagatingExecutor. Sample smartly: lower rates on noisy paths; raise for errors. Logs Use JSON layout; include traceId/spanId for correlation. Avoid verbose INFO in hot paths; keep payload size bounded. Dashboards & alerts Latency/error SLO dashboards per endpoint. DB pool saturation, thread pool queue depth, GC pause, heap used %, 5xx rate. Alerts on SLO burn rates; include exemplars linking metrics → traces → logs. Checklist Actuator endpoints secured and exposed only where needed. OTLP exporter configured; sampling tuned. Trace/log correlation verified in staging. Dashboards + alerts reviewed with oncall.