Question

Why do we need the applications in the cloud to be stateless?

Answer 1

A stateless app is an application program that does not save client data generated in one session for use in the next session with that client. Each session is carried out as if it was the first time and responses are not dependent upon data from a previous session. In contrast, a stateful application saves data about each client session and uses that data the next time the client makes a request.

Programmers, feeling that they need to save information about particular users between interactions, find all sorts of ways to use sessions that are not really appropriate. As a result, the concept of sessions gets abused and the scalability of the applications suffers due to requiring sessions.

If you can design your application not to use sessions at all when running in the cloud, Your processes can vanish at a moment’s notice with no warning, and that’s a good thing. Processes come and go, scale horizontally and vertically, and are highly disposable. Also, the application will run much better under high load than if you try to keep track of which user needs to be reconnected with which session settings.