Model for enabling convenient on-demand network access to a shared pool of configurable computing resources (e.g. networks, servers, storage, applications and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. Users do not need to invest in their own infrastructures. Storage and processing takes place in the cloud rather than at the user's premises or on the user's devices. Cloud services can rapidly scale up or down according to demand, giving the "illusion of unlimited resources". Computing becomes an operating, rather than a capital expenditure item.
Cloud-based computing can be defined as :
- automatic: users can unilaterally provision computing capabilities as needed, automatically and without requiring human interaction with each service provider.
- metered: resources/tools are offered on a pay-as-you-use basis.
- online: capabilities are available from any device using an network connection.
- shared: providers offer their services to multiple users. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources.scalable/elastic: Capabilities can be elastically provisioned and released, in some cases automatically. To the user, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.