Distributed Tracing

Microservices make slow requests harder to debug because one request often crosses many services, databases, caches, queues, and external APIs.

Each service may look fast in isolation, but the full request can still be slow because of retries, network latency, queue delays, or slow downstream calls.

Distributed tracing connects these scattered steps into one end-to-end view.

This chapter covers traces, spans, trace context, OpenTelemetry, sampling, and the common problem of missing spans.