Explore the five key characteristics: on-demand self-service, resource pooling, rapid elasticity, broad network access, and measured service.
The National Institute of Standards and Technology (NIST) defines five essential characteristics that an offering must possess to be considered a true cloud service. First, 'On-demand self-service' means a consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider. Second, 'Broad network access' implies that capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations). Third is 'Resource pooling', where the provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. Fourth, 'Rapid elasticity' allows capabilities to be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time. Finally, 'Measured service' means cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts).