It very well could be running on the same machine, and communicating with the app using unix sockets, which is a hell of a lot faster than TCP. But no one seems to be doing that much either.

I feel that the virtualize and distribute everything to hell and back-trend might actually be about to break, there are signs, and G knows it's about time. The amounts wasted on cloud providers for apps that would run everything just fine on a single server, the effort wasted configuring their offerings, surreal.