IaaS (Infrastructure as a Service)

IaaS (Infrastructure as a Service) is the foundational cloud computing model, in which a provider delivers virtual infrastructure resources on demand: compute servers, storage, networking and IP addresses. The customer neither buys nor maintains physical hardware, but rents its virtualized equivalents and pays for actual usage. Of the three classic cloud layers, IaaS offers the most control and sits closest to the hardware.

How IaaS works

The foundation of IaaS is virtualization — a hypervisor divides physical servers into many isolated virtual machines that can be created, scaled and destroyed in moments through a portal or API. A shared-responsibility model applies: the provider looks after the data center, hardware, power and virtualization layer, while the customer manages everything above — the operating system, configuration, security and applications. Programmatically provisioned resources let you treat infrastructure as code and rebuild entire environments automatically.

IaaS vs PaaS and SaaS

The three cloud layers differ in their level of abstraction. IaaS delivers raw infrastructure and requires self-administration. PaaS goes a step further, offering a ready runtime platform where the provider also manages the OS and environment — the developer supplies only code. SaaS is a finished application accessed through a browser, where the customer manages nothing beyond their own data.

Practical application

IaaS shines wherever flexibility and full control over the environment matter: variable workloads, test environments spun up for a moment, hosting applications with non-standard requirements, or building a high availability architecture. In practice, the simplest form of IaaS is renting a VPS, which provides full administrative access to a machine in the cloud without investing in your own hardware.