Answers

1. Trace IDs and span IDs are created when the distributed transaction is initiated. A trace ID is generated for the main API call by the receiving service using Spring Cloud Sleuth. A trace ID is generated only once for each distributed call. Span IDs are generated by all the services participating in the distributed transaction. A trace ID is a correlation ID that will be common across the service for a call that requires a distributed transaction. Each service will have its own span ID for each of the API calls.
2. Yes, a broker such as Kafka, RabbitMQ, or Redis allows robust persistence of logs and removes the risk of losing log data in unavoidable circumstances. It also performs better and can handle sudden spikes of data.
3. A tracer such as Micrometer with Brave or Spring Cloud Sleuth (which performs instrumentation) does two jobs – records the time and metadata of the call being performed, and propagates the trace IDs to other services participating in the...