The RESTless cloud.

Cloud provider APIs have emerged as the de facto operating system interface for the warehouse scale computers that comprise the public cloud. Like single-server operating systems, they provide the resource allocation, protection, communication paths, naming, and scheduling for these large machines. Cloud provider APIs also provide all sorts of things that operating systems do not, things like big data analytics, machine learning model training, or factory automation. Somewhere, lurking within this menagerie of services, there is an operating system interface to a really big computer, the computer that today's application developers target. This computer works nothing like a single server, yet it also isn't a dispersed distributed system like the internet. It is something in-between. Now is the time to distill and refine a coherent "cloud system interface" from the multitude of cloud provider APIs, preferably a portable one. In this paper we discuss what goes in, what stays out, and the principles that inform these decisions.