We have learned that the application consists of several microservices. What exactly does the request flow look like? It is time to look at the actual trace. Let's go to the Search page in the Jaeger UI. Under the Find Traces caption, the Services dropdown contains the names of the services we saw in the dependency diagram. Since we know that frontend is the root service, let's choose it and click the Find Traces button.
Figure 2.5: Results of searching for all traces in the last hour from the service frontend
The system found two traces and displayed some metadata about them, such as the names of different services that participated in the traces, and the number of spans each service emitted to Jaeger. We will ignore the second trace that represents the request to load the JavaScript UI and focus on the first trace, named frontend: HTTP GET /dispatch. This name is a concatenation of the service name frontend and the operation name of the top-level span, in this case HTTP GET...