Why Distributed Tracing Matters
Follow a request across many services.
Why Distributed Tracing Matters is a free Spring Boot 4 Microservices & REST APIs lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Spring Boot 4 Microservices & REST APIs learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
The microservices visibility gap
When one user request flows through many services, a failure or slowdown is hard to locate. Distributed tracing stitches the whole journey into a single, viewable timeline.
Trace and span
Two core concepts:
- A trace represents one end-to-end request
- A span represents one unit of work within it (e.g. a single service call)
Trace and span IDs
Every trace gets a traceId; every span gets a spanId and a reference to its parent span. These IDs propagate from service to service so the pieces can be reassembled.
Context propagation
The trace context is carried between services, usually in HTTP headers (e.g. W3C traceparent). Downstream services read it and continue the same trace instead of starting a new one.
// example incoming header (W3C Trace Context)
// traceparent: 00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01What a trace reveals
A trace view shows each span's duration as a waterfall, so you instantly see which service is the bottleneck, where an error originated, and how calls fan out.
Three pillars of observability
Tracing complements the other two pillars:
- Metrics - aggregated numbers (latency, throughput)
- Logs - discrete events
- Traces - causal request flow across services
Where Micrometer fits
Micrometer Tracing is Spring's tracing abstraction. It creates and propagates spans for you, with pluggable backends (Brave/OpenTelemetry) and exporters (Zipkin).
Where Zipkin fits
Zipkin is a tracing backend: services send their finished spans to it, and it stores and visualizes the assembled traces in a web UI.
Automatic instrumentation
Much instrumentation is automatic: incoming HTTP requests, RestTemplate/WebClient calls, and messaging get spans without code changes once tracing is on.
Sampling
Tracing every request can be expensive. Sampling records only a fraction of traces. A probability like 0.1 records 10%, balancing insight against overhead.
management:
tracing:
sampling:
probability: 0.1 # sample 10% of requestsThe payoff
With tracing, debugging a slow or failing distributed request changes from guesswork across many logs to opening one trace and reading the waterfall. It is essential at scale.
Quick Check
Confirm the core tracing concepts.
Recap
You learned why tracing matters:
- A trace = whole request; a span = one unit of work
- traceId/spanId propagate via headers across services
- Micrometer creates spans; Zipkin stores and visualizes them
- Sampling controls overhead
Frequently asked questions
Is the “Why Distributed Tracing Matters” lesson free?
Yes — the full text of “Why Distributed Tracing Matters” is free to read here on the web, and the Spring Boot 4 Microservices & REST APIs course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Spring Boot 4 Microservices & REST APIs course, upgrade to CoddyKit PRO.
What will I learn in “Why Distributed Tracing Matters”?
Follow a request across many services. You practise Spring Boot 4 Microservices & REST APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Spring Boot 4 Microservices & REST APIs?
No prior experience is required. Spring Boot 4 Microservices & REST APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Why Distributed Tracing Matters” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Spring Boot 4 Microservices & REST APIs lesson?
Yes. Every Spring Boot 4 Microservices & REST APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Why Distributed Tracing Matters
- Micrometer Tracing
- Exporting Traces to Zipkin
- Correlating Logs and Traces