Sample stack for testing OTEL functionality with moby

To easily test the OTEL functionality present in moby, you can spin up a small demo compose stack that includes:

• an OTEL collector container;
• a Jaeger container to visualize traces;
• an alternative Aspire Dashboard container to visualize traces;

The OTEL collector is configured to export Traces to both the Jaeger and Aspire containers.

The contrib/otel directory contains the compose file with the services configured, along with a basic configuration file for the OTEL collector.

How can I use it?

1. Export the env var used to override the OTLP endpoint:
   export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318 (if running in a devcontainer or in other ways, you might have to change how you pass this env var to the daemon);
2. Start the moby engine you want to get traces from (make sure it gets the env var declared above);
3. Start the otel compose stack by running docker compose up -d in the contrib/otel/ directory;
4. Make some calls to the engine using the Docker CLI to send some traces to the endpoint;
5. Browse Jaeger at http://localhost:16686 or the Aspire Dashboard at http://localhost:18888/traces;
6. To see some traces from the engine, select dockerd in the top left dropdown

Note: The precise steps may vary based on how you're working on the codebase (buiding a binary and executing natively, running/debugging in a devcontainer, etc... )

Cleanup?

Simply run docker compose down in the contrib/otel/ directory.

You can also run unset OTEL_EXPORTER_OTLP_ENDPOINT to get rid of the OTLP env var from your environment