What is Infrastructure as a Service (IaaS)?

IaaS stands for Infrastructure as a Service. NIST (SP 800-145) defines it as provisioning processing, storage, and networks to run any software, which can include operating systems. Think of it as renting the basics of a computer system – servers, storage, and networking – from a cloud provider rather than buying and maintaining your own hardware.

Think of it as renting an equipped kitchen rather than building one.

IaaS, PaaS, and SaaS are the three main types of cloud computing services:

• IaaS (Infrastructure as a Service): You rent the basics (virtual servers, storage, networking) and then build your applications and systems on top of them.
• PaaS (Platform as a Service): A complete platform with tools and services for developing, deploying, and managing applications.
• SaaS (Software as a Service): Software applications for use over the internet, without installing or maintaining them yourself.

The difference between IaaS and SaaS is the amount of control and responsibility you have. With IaaS, you have more control and responsibility, whereas with SaaS, you have less.

IaaS is like renting a plot of land and constructing a house. PaaS is like renting an apartment. SaaS is like renting a furnished apartment.

IaaS offers such things as:

• Cost: Direct hardware investments are not a prerequisite, and maintenance expenditures typically manifest at a lower degree. IaaS is usually billed pay-as-you-go for the resources you use.
• Flexibility: The operating system, software, and configurations can be specified by the user.
• Availability: Redundant infrastructure correlates with the availability of data and applications.
• Scalability: It involves modifying resource levels to align with shifts in demand.

This makes IaaS a way for companies to access computing resources without managing their own infrastructure. Under the hood, IaaS relies on virtualization: the provider creates virtual versions of its servers, storage, and networks that behave like physical ones (AWS).

IaaS is for: businesses with fluctuating workloads, startups, and organizations that need to deploy applications or test environments.

IaaS is used by businesses and individuals:

• Startups: launch and scale without investing in infrastructure
• Enterprises: modernize their IT infrastructure and cut costs.
• Developers: set up development and testing environments
• Anyone who needs access to computing resources.

IaaS is a partly managed service: in NIST’s definition (SP 800-145), you control the operating systems, storage, and deployed applications, but not the underlying cloud infrastructure (NIST). This gives you more control but also requires more technical expertise.

If you lack the technical skills or resources to manage your own infrastructure, consider PaaS or SaaS solutions, which offer a higher level of abstraction. One provider can offer both models: on Azure, Microsoft describes IaaS as provisioning virtual machines, while App Service and Container Apps are its platform as a service (PaaS) offerings (Microsoft Learn). But if you need control over your environment and want to customize it, IaaS is recommended.