Cloud computing is offered in three distinctly different service model, each designed to satisfy a different set of business requirements. The service models are SaaS, PaaS, and IaaS.
SaaS, short for Software as a Service, is for customers. Customers are able to simply use it without worrying about any technical matters. These are services like gmail, Googledocs, and Microsoft Office 365.
PaaS, short for Platform as a Service, is for developers. It allows offers pre-built infrastructure. Developer can work on this infrastructure without having to manage the underlying infrastructure. These are services like Heroku.
IaaS, short of Infrastructure as a Service, is for system administrators. It is the basic building blocks of cloud IT. With IaaS, admins have full control infrastructure features such as networking, storage, and database. However, this means that they also the have full responsibility of building and maintaining the infrastructure.
- Infrastructure as a Service (IaaS):
- User pay-as-you-go access to resources (CPU, memory, storage, networking) in the cloud.
- For system administrators
- Example: AWS, CCP, Azure
- Platform as a Service (Paas):
- For developers
- User uses the cloud to build and deliver applications. Cloud provides the underlying infrastructure.
- Example: Heroku
- Software as a Service (SaaS):
- For customers
- User delivers software and applications to its customers through the Internet.
- Microsoft Office 365 and Googledocs are SaaS services.