Explain the differences between cloud models IaaS, PaaS, and SaaS

Cloud models IaaS, PaaS, and SaaS differ in the level of services provided and the degree of management by the user:

• IaaS (Infrastructure as a Service) — infrastructure as a service.

  • The user gets virtual servers, storage, networks.
  • Manages operating systems, applications, data.
  • Example: Amazon EC2, Google Compute Engine.

• PaaS (Platform as a Service) — platform as a service.

  • Provides a platform for developing and deploying applications.
  • The user manages only applications and data.
  • Infrastructure and runtime environment are managed by the provider.
  • Example: Google App Engine, Heroku.

• SaaS (Software as a Service) — software as a service.

  • Ready-made applications accessible via the internet.
  • The user uses the application without managing infrastructure or platform.
  • Example: Gmail, Microsoft Office 365.

Thus, IaaS provides basic infrastructure, PaaS — a development platform, and SaaS — ready-made applications.