This is part three in a series where I learn OpenTelemetry (OTEL) from scratch. If you haven't yet seen them yet, part 1 is about setting up auto-instrumented tracing for Node.js and part 2 is where I initially implemented the OTEL collector. Today we are going to begin experimenting with sampling. We need to sample traces because we capture so much data! It would be impractical to process and store it all (in most cases).

In the previous article I covered how to set up auto-instrumented tracing for a Node.js app using OpenTelemetry (OTEL). We then sent the spans directly to the open source tracing tool Jaeger. I recommend you give that a read first before walking through this guide because we're going to re-use the instrumentation we set up last time. Today we're going to take things a step further by introducing the OpenTelemetry Collector.