IaaS in cloud computing is when you rent access to cloud infrastructure resources as individual services from a cloud service provider (CSP), including servers, virtual machines, networking resources, and storage. IaaS helps eliminate much of the complexity and costs associated with building and maintaining physical infrastructure in an on-premises data center.  

The CSP is responsible for managing and maintaining the infrastructure, so you can concentrate on installing, configuring, and managing software and keeping your data secure. IaaS providers also offer additional services, such as detailed billing management, logging, monitoring, storage resiliency, and security. 

You can access IaaS resources using a pay-as-you-go basis, allowing you to only pay to consume the resources that you need. In other words, you can easily increase or decrease resources, allowing you to pay less when needed or instantly provision and scale out resources to meet new demand.

Like other “as a service” models, such as Platform as a service (PaaS) and Software as a service (SaaS), infrastructure as a service models offer a degree of management. But what exactly is the difference between IaaS, PaaS, and SaaS? The answer is that they each provide a different cloud service: an infrastructure environment versus platform tools versus complete applications.

Depending on the service type you choose, the CSP manages different elements of the computing stack:

For IaaS models, the service provider hosts, maintains, and updates the backend infrastructure, such as compute, storage, networking, and virtualization. You manage everything else including the operating system, middleware, data, and applications. 

IaaS examples: Compute Engine, Cloud Storage.

Like IaaS models, for PaaS models, the service provider delivers and manages the backend infrastructure. However, PaaS models provide all the software features and tools needed for application development. You still have to write the code and manage your apps and data but do not have to worry about managing or maintaining the software development platform.

PaaS examples: Cloud Run, App Engine.

With SaaS service models, the service provider delivers the entire application stack—the complete application and all the infrastructure needed to deliver it. As a customer, all you have to do is connect to the app through the internet—the provider is responsible for everything else. 

SaaS examples: Google Workspace.

Unlike traditional on-premises environments, cloud security is a shared responsibility between service providers and their customers. 

With IaaS models, the CSP secures the resources and other hardware that support the underlying infrastructure, including compute, storage, patching, and the physical network. As a customer, you will be responsible for securing your data, applications, virtual network controls, operating system, and user access. 

While security is often cited as one of the disadvantages of IaaS and cloud computing in general, the truth is that cloud is no more or less secure than on-premises environments. In fact, it can offer more comprehensive protection against threats. 

Reputable cloud service providers also offer secure-by-design infrastructure and robust cloud security services on their platforms that often exceed what you can accomplish on your own. They are constantly investing in advanced technologies and highly skilled experts, enabling them to provide the latest security capabilities and solutions to help protect every layer of computing. 

In other words, IaaS security is only as secure as your cloud service provider makes it. Therefore, it’s extremely critical that you carefully evaluate providers and thoroughly understand their security capabilities and responsibilities before making a decision.

IaaS helps reduce your upfront capital expenditures. Resources are used on demand, meaning you only have to pay for the compute, storage, and networking resources that you consume. IaaS costs are fairly predictable and can be easily contained and budgeted for. 

IaaS resources are regularly available to businesses when they need them. As a result, organizations can reduce provisioning delays when expanding infrastructure and, alternatively, avoid wasting resources by overbuilding capacity. 

IT teams not only have more time to spend on strategic work, IaaS makes it fast and affordable to test new products and ideas. You can easily spin up the necessary computing infrastructure without having to wait days or weeks for it to be ready, speeding up development lifecycles and time to market. 

IaaS platforms have no single point of failure. Cloud infrastructure offers built-in redundancy and fault tolerance, with workloads spread across multiple servers and facilities. Even if one component of the hardware resources fails, the service will usually remain available. 

One of the biggest advantages of IaaS in cloud computing is the capability to automatically  scale resources up and down rapidly. You can accommodate sudden spikes in demand almost instantly and scale back when the resources are no longer required. 

Most cloud service providers achieve greater availability and resiliency with the help of a global network that covers multiple geographies. You can minimize latency and increase performance by placing apps and services in the regions and zones closest to your end users.