Nearly every application has some kind of state (of course, one can develop a stateless service, which does not have to store a state anywhere and just performs an action/returns a result; we will cover such services later in this chapter).
This state has to be managed and shared; in monolithic application handling, it is pretty straightforward and obvious—we have, for instance, a database, which holds all information from multiple parts of our system. In general, it is stored in one place (of course it can be scaled and shared, but we do not manage such features on our own), so we do not have to worry that we update it only partially (and if we do, there are always transactions). Of course, the state does not have to be ...
