What is Infrastructure as a Service (IaaS)?

IaaS (infrastructure as a service) is a type of cloud computing that offers virtualized compute, storage, and networking wrapped together as a self-service platform upon which customers can deploy and run applications with minimal fuss.

The household names of cloud computing—AWS (Amazon Web Services), Microsoft Azure, and Google Cloud—are IaaS providers. All three maintain giant data centers around the world that include tons of physical servers, storage systems, and networking equipment under a virtualization layer that enables cloud customers to allocate those resources in a highly automated manner.

Key to the value of IaaS is the ability to provision and scale up virtualized resources on demand for any workload. Organizations that use IaaS can self-provision infrastructure services and pay for them on a per-use basis. Fees are typically paid by the hour, week, or month, depending on the service contract. In some cases, providers charge clients for infrastructure services based on the amount of virtual machine (VM) capacity they’re using over time.

Atop that virtualized infrastructure, the leading IaaS clouds have cultivated vast ecosystems of services, from globally distributed relational databases to data warehouses to machine learning libraries to IoT management solutions. Today, a frequent motivation to choose an IaaS provider is to gain access to new, innovative technology that would be difficult to spin up on premises. Some of these advanced services are developed and delivered by the provider, while others are proffered by third-party tenants on the IaaS platform—again, on a per-use basis.

IaaS vs. PaaS vs. SaaS

IaaS is one of three main types of cloud services, along with software-as-a-service (SaaS) and platform-as-a-service (PaaS). Like PaaS and SaaS, IaaS offers access to its services across a public connection that’s typically the internet. But IaaS alone provides full access to the underlying virtualized resources, plus an expansive selection of cloud software and services on top.