[wsargent]

MDC/NDC only reliably works when you don't have asynchronous code (Akka/Vert.x/CompletionStage) through your application. As soon as you start using multiple threads, it becomes significantly more complex to keep MDC context carried over from one thread to the next.

[kaba0]

Well, that has more to do with reactive programming not playing by the rules. Once Loom arrives with Extent-Local scopes it will solve it very well.