Clouds

Cloud computing refers to the ability to provision computing infrastructure and higher-level services for an application from an external provider over the internet. Companies offering these multi-tenant computing services are called cloud providers and typically charge on a pay-per-use basis, thus enabling delivery of infrastructure and services in a utility model.

In the spirit of service-oriented architecture, cloud computing is packaged in three broad flavors, which are described next.

Infrastructure as a Service (IaaS)

Here, the cloud provider gives users direct access to computing resources such as servers, storage, and networking. Organizations use this and deploy their own technology stack of this infrastructure...