Читать книгу The Official (ISC)2 CCSP CBK Reference - Leslie Fife, Aaron Kraus - Страница 14

There are three service models: software as a service (SaaS), platform as a service (PaaS), and infrastructure as a service (IaaS). These models determine the type of user the cloud service is designed for: end users, developers, or system administrators.

The different service models also dictate the level of control over software applications, operating systems, networking, and other components. The least control for the end user exists in the SaaS model, with only basic configuration controls available, if any. The most control for the end user is the IaaS model where operating system selection and configuration, patching, and software tools and applications are under the control of the end user.

When the service is provided to a company, the distinction can be less clear. While a PaaS may be intended for use by developers, there may be some administration of the service by the company as well. In fact, the lines often blur when a corporation enters into a business relationship with a cloud provider but does much of the provisioning and administrative work in house.

For example, Office 365 can be considered a SaaS solution, and to the individual consumer there is little or no administrative overhead. But, if a company contracts for Office 365, they may in fact administer the system, overseeing account provisioning, system monitoring, and other tasks that would be the domain of developers and administrators.