Instruct X-DevOps - OpenTelemetry - Jaeger

This laboratory demonstrates the key aspects of Jaeger and OpenTelemetry, both monitoring tools for applications. It was created for Instruct's 2023 Summit X-DevOps presentation.

Presentation

The slides with the presentation can be found at:

https://docs.google.com/presentation/d/1edvxXQUpAjwI070CLqF9Hkv7Srj3DJCPqM6qoUkFgog/edit?usp=sharing

How to prepare the lab environment (Linux or WSL environment)

1. Copy the content of calculator-api/.env.sample to a new file calculator-api/.env, and the content of blackjack-api/.env.sample to a new file blackjack-api/.env.

2. Start the docker containers

   docker-compose up -d --build

   The command starts the:

   • Jaeger all-in-one service. The UI is at http://localhost:16686/.
   • PostgreSQL database.
   • Blackjack API service at http://localhost:8001/api/blackjack/.
   • Calculator API service at http://localhost:8002/api/calculator/.

How to run the lab (Linux or WSL environment)

1. Go to the Jaeger UI and search for traces on the blackjack-api service. The will already be traces related to the start of the service.

2. Make a get request to start a game of blackjack:

   $ curl http://localhost:8001/api/blackjack/deal/

3. Go back to the Jaeger UI, search again for traces on the blackjack-api service, and click on the most recent trace with the address api/blackjack/deal/$.

4. On the tab Service & Operation, select the blackjack-api api/blackjack/deal/$ span and open it's Tags tab. Look for the operation.* tags. Those were set on code to provide more context on the request.

5. Open the blackjack-api SELECT and open it's Tags tab. Look for the db.statement tag. It should show the query made on the database.

6. Look for the calculator-api api/calculator/sum/$ span. It should have a different color, indicating it's from a diferent system. Open the span's Tags tab and look for the operation.* tags. They were also set on code, similarly as before.

7. Now make a get request to force an exception:

   $ curl http://localhost:8001/api/blackjack/cheat/

8. Go back to the Jaeger UI, search again for traces on the blackjack-api service, and click on the most recent trace with the address api/blackjack/cheat/$.

9. On the tab Service & Operation, select the blackjack-api api/blackjack/deal/$ span and open it's Log(s) tab. Open the first log and you will see the details of the exception.

10. Finally, on the navigation menu on top of the screen, select the System Architecture option. You can see how the services relate to each other, as well as how many traces are between them. (It is easier to see on the DAG tab).