Infrastructure as a Service, the abbreviation IaaS is used. IaaS is a modern term, which replaced the original HaaS (Hardware as a Service). The change involves also the way of management. In the case of IaaS, it is the provision of computing performance, infrastructure and storage, most often through virtualization. The customer therefore rents the hardware and infrastructure, not the application software. A typical example of IaaS category are various web hosting services or virtual storage.
IaaS is typically provided on a contract basis, including the definition of SLA.