From PaaS — to the Cloud Operating System

Currently, there are two competing factions of cloud computing — IaaS and PaaS. With IaaS, application developers work with a number of virtual machines, each with its own operating system. PaaS replaces this by a collection of cloud-wide services which applications can use. In this paper we make, and justify, the analogy of PaaS being the cloud’soperating system. We claim that as PaaS is maturing, every cloud application will use PaaS services, making the application much easier to write, more flexible and often more efficient. We explain why PaaS is better implemented as part of the cloud system, not the application, and is therefore better thought of as an operating system than a library. We predict that writing new cloud applications on IaaS (without PaaS) will soon be just as uncommon as applications that run on a computer without an operating system. We explore the details of this analogy, explore how PaaS will need to evolve to become more effective in its new role of the cloud operating system, and propose new directions for operating system research in the cloud era.