Metrics tell you something is wrong. These three signals keep the detail needed to say what.
| # | Lesson | The question it answers |
|---|---|---|
| 01 | Structured Logs and Wide Events | How do I record what happened so a machine can query it? |
| 02 | Distributed Tracing | How do I follow one request through many services? |
| 03 | OpenTelemetry | What is the standard that ties the signals together? |
| 04 | Profiling and eBPF | Which code is using the CPU, and how can I see without changing the program? |
When you finish you can emit one wide event per request, propagate a trace across an HTTP call, explain every box in an OpenTelemetry pipeline, and read a flame graph.