The Cloud is now a ubiquitous term with a plethora of meanings. Many vendors are guilty of “cloudwashing”, which is a marketing technique to associate a product or service with The Cloud that was not initially intended, there are some generally accepted definitions. While Nicholas Carr certainly captured the concept in his books Does IT Matter and The Big Switch, NIST (National Institute of Standards and Technologies) published some very practical and detailed verbiage early in 2011 on “essential characteristics”.
- On-demand self-service. A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service’s provider.
- Broad network access. 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, laptops, and PDAs).
- Resource pooling. 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. 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 but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of resources include storage, processing, memory, network bandwidth, and virtual machines.
- Rapid elasticity. Capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out, and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.
- Measured Service. 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). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.
Arguably we have all seen this before under the moniker of timesharing, outsourcing, colo, and application service providers (ASP), but there is a slightly different spin on the latest incarnation.
The Cloud also carries its own risks that must be addressed.