Essential Characteristics


  • Resource pooling is the most fundamental characteristic, as discussed above. The provider abstracts resources and collects them into a pool, portions of which can be allocated to different consumers (typically based on policies).
  • Consumers provision the resources from the pool using on-demand self service. They manage their resources themselves, without having to talk to a human administrator.
  • Broad network access means that all resources are available over a network, without any need for direct physical access; the network is not necessarily part of the service.
  • Rapid elasticity allows consumers to expand or contract the resources they use from the pool (provisioning and deprovisioning), often completely automatically. This allows them to more closely match resource consumption with demand (for example, adding virtual servers as demand increases, then shutting them down when demand drops).
  • Measured service meters what is provided, to ensure that consumers only use what they are allotted, and, if necessary, to charge them for it. This is where the term utility computing comes from, since computing resources can now be consumed like water and electricity, with the client only paying for what they use.
ISO/IEC 17788 lists six key characteristics, the first five of which are identical to the NIST characteristics. The only addition is multitenancy, which is distinct from resource pooling.

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