Now that we have seen what the HotROD application does, we may want to know how it is architected. After all, maybe all those servers we saw in the logs are just for show, and the whole application is simply a JavaScript frontend. Rather than asking someone for a design document, wouldn't it be great if our monitoring tools could build the architecture diagram automatically, by observing the interactions between the services? That's exactly what distributed tracing systems like Jaeger can do. That request for a car we executed earlier has provided Jaeger with enough data to connect the dots.
Let's go to the Dependencies page in the Jaeger UI. At first, we will see a tiny diagram titled Force Directed Graph, but we can ignore it, as that particular view is really designed for showing architectures that contain hundreds or even thousands of microservices. Instead, click on the DAG tab (Directed Acyclic Graph), which shows an easier-to-read graph. The graph layout is non-deterministic...