Introduction In this post, we'll walk through the components required to instrument a Python application with Datadog APM, and how to configure them in a Docker environment. A common shorthand is "just install the Datadog Agent and the tracing library and you're good to go" — and while that's essentially correct, understanding what each component is actually doing under the hood makes troubleshooting dramatically easier when things go wrong. If you've ever stared at an empty APM dashboard wondering why your traces aren't showing up, this guide should help you build a clearer mental model of how the pieces fit together. The Building Blocks of Datadog APM To instrument an app with Datadog APM, you need to set up two things: the Agent side and the library side . Agent Side: The Trace Agent When you enable APM in the Datadog Agent, an internal component called the Trace Agent starts up. The Trace Agent is responsible for receiving trace data sent from your application and forwarding it to Datadog's backend.…