Distributed Tracing

This gets you tracing infrastructure with Jaeger or Zipkin so you can follow requests bouncing between microservices. You'll use it when debugging why something's slow or figuring out where a request died in your service mesh. The skill covers both Jaeger and Zipkin setups with Docker Compose, plus instrumentation examples for Node.js and Python including the critical bit about propagating trace context between services. The best practices section is solid on sampling strategy, which matters because tracing everything in production will wreck your performance. It's straightforward observability plumbing that assumes you already have microservices that need connecting.