Infrastructure as a Service (IaaS)

Infrastructure as a service (IaaS) is the cloud model that delivers core computing building blocks on demand: virtual machines, virtual networks, block and object storage, and load balancers. The provider operates the physical hardware and virtualization layer, while the customer manages operating systems, runtimes, applications, and most configuration.

How It Works

Customers provision resources through a console, API, or infrastructure-as-code tools. They choose instance sizes, attach storage volumes, configure networks and firewalls, and install whatever software they need. Billing is usage-based, often per second or per hour for compute and per gigabyte for storage. Because customers control the operating system and stack, IaaS offers the most flexibility of the cloud service models, at the cost of more operational responsibility for patching, scaling, and securing the environment. Examples include Amazon EC2, Azure Virtual Machines, and Google Compute Engine.

Why It Matters

IaaS gives organizations cloud flexibility close to running their own data center, without the capital expense or hardware lead times. It suits workloads that need specific operating systems, custom configurations, or lift-and-shift of existing applications. The trade-off is that the customer carries more of the shared-responsibility burden than with platform-as-a-service or serverless. Teams often combine IaaS for specialized workloads with higher-level managed services where they want less operational overhead.

Related Terms

IaaS sits below platform-as-a-service in abstraction and provides the virtual private clouds, block storage, and object storage that applications build on.