Periodically examine the subject of clouds. By all definitions, the cloud is some spherical horses in a vacuum that somehow (no matter how) solves complex technical problems of building distributed systems and providing a service to the user at a higher logical level. Inside clouds, how they work — the user should not worry on it and the "cloud" and not "a set of tambourine, cheshek and Mat dancing".
However, we still see any blatant profanity (when a normal, dedicated and VPS hosting with instant activation use the word "cloud" in advertising), or constructors, where a higher logical level, there is no (Amazon — you need to explore all of its API to get it all together + all services there are nuances).
There was a time when I was happy, having found vps.net — thought instance you can combine nodes from different cities. But no — this cannot be done, it's just a vps with a beautiful sauce.
PS Cloud hosting interested in, not because I have some megachilid services, but because they want distribution for reliability and speed.
P. P. S. Noda, the minimum virtual unit, which operates a cloud-based hosting, a piece of computer. Instance — ready, assembled the essence of who websites.