In defining Infrastructure as a Service we need to drill into specific characteristics that a cloud platform provider must provide to be considered Infrastructure as a Service. This has been no easy task as nearly every cloud platform provider has recently promoted features and services designed to address the infrastructure as a service and cloud computing market. Fortunately, as the technology has evolved over time, a definition of cloud computing has emerged.

As a metaphor for the Internet, "the cloud" is a familiar cliché, but when combined with "computing," the meaning gets bigger and fuzzier. Some analysts and vendors define cloud computing narrowly as an updated version of utility computing: basically virtual servers available over the Internet. Others go very broad, arguing anything you consume outside the firewall is "in the cloud," including conventional outsourcing.
Cloud computing comes into focus only when you think about what IT always needs: a way to increase capacity or add capabilities on the fly without investing in new infrastructure, training new personnel, or licensing new software. Cloud computing encompasses any subscription-based or pay-per-use service that, in real time over the Internet, extends IT's existing capabilities.

Migration to the Cloud

The hype surrounding cloud services may make it seem like all of an organization's resources should be migrated to the cloud immediately. There is no denying that, in certain cases, cloud services can be tremendously beneficial. In others, however, a cloud migration probably does not make sense.
Organizations need to take a hard look at their existing investments in infrastructure -- from hardware to application portfolios to network architecture and beyond -- to determine if a move will be beneficial. Some of the migration questions are technical, such as whether a given application can perform adequately in the cloud; some questions will involve nontechnical, budgetary issues, such as whether a cloud migration is cost-effective given current investments in infrastructure.