If you ask five different experts you will get maybe five different opinions what cloud computing is. And all five may be correct. The best definition of cloud computing that I have ever found is the National Institute of Standards and Technology Definition of Cloud Computing. According to NIST the cloud model is composed of five essential characteristics, three service models, and four deployment models. In this post I will look at the essential characteristics only, and compare to the traditional computing models; in future posts I will look at the service and deployment models.
Because computing always implies resources (CPU, memory, storage, networking etc.), the premise of cloud is an improved way to provision, access and manage those resources. Let’s look at each essential characteristic of the cloud.