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IaaS: Infrastructure as a service 

What is IaaS? An overview of infrastructure as a service

Infrastructure as a Service, or IaaS, is the provisioning of the basic computing resources required to deploy enterprise systems over the Internet. This includes storage, hardware, servers and networking components. With IaaS, the physical infrastructure of IT systems is typically moved offsite and a service provider grants access to a virtualized environment of computing resources to its customers.

So how is IaaS different from other cloud offerings such as Software as a Service (SaaS) and Platform as a Service (PaaS)? One way to distinguish the three is to think of cloud computing as a stack of service layers, each of which corresponds to one of the three tiers in the application-middleware-hardware architecture of traditional enterprise systems. At the top of the cloud stack is SaaS, followed by PaaS in the middle, and IaaS at the bottom.

SaaS includes business applications offered by vendors such as Salesforce.comSuccessFactors, and Inuit. Enterprises use such applications to run their day-to-day operations, ranging from order processing and production scheduling to billing and customer information management.

Sitting between the SaaS and IaaS layers, PaaS is a development platform for building and running applications in the cloud. The category includes application servers, integration brokers, databases and database management systems. It is further divided into two sub-categories: Application Platform as a Service (aPaaS) and Integration Platform as a Service (iPaaS). aPaaS products such as (by, Google App Engine, and Microsoft’s Windows Azure provide cloud hosting services and development tools while iPaaS products such as CloudHub are designed to facilitate the integration of applications across the enterprise, with partner enterprises, and other cloud services.


Underlying the SaaS and PaaS layers is IaaS. IaaS provides a layer of virtualized hardware that delivers the computing power and data centers required for applications to run, serving as a foundation for SaaS and PaaS. Amazon Elastic Cloud Compute (Amazon EC2), Rackspace Cloud Servers, GoGrid, Joyent, and AppNexus are examples of IaaS vendors that are transforming enterprise systems by delivering crucial infrastructure components and computing resources to developers and administrators on demand.

IaaS: Benefits and use cases

Like other cloud offerings, IaaS takes advantage of the elasticity and flexibility of the cloud to deliver infrastructure, with tangible benefits for enterprises. IaaS allows cloud adopters to choose when, how, and what computing resources to consume and to scale up or down as demands change, drastically reducing time to market. Since the IaaS vendor is responsible for configuring and maintaining the infrastructure, enterprises don’t have to worry about infrastructure upgrades and can focus on rolling out applications instead.

Moreover, by outsourcing the task of building and maintaining infrastructure to a service provider, enterprises can reduce capital expenditures on hardware and software. With a pay-as-you-go pricing model, enterprises only pay for the resources they use in a given period. These financial incentives are especially appealing to startups and small and mid-sized companies that have limited capital but need state-of-the-art IT systems to run their businesses.

While the reduction of IT costs by migrating to virtualized servers and the enhancement of business agility through the use of on-demand computing resources are perhaps the most common reasons for adopting IaaS as a long-term strategy, short-term needs also make good IaaS use cases. For instance, IaaS can be leveraged in seasonal marketing campaigns and promotions to deploy web applications on a short-term basis without paying upfront costs to increase computing capacity. When the promotion ends, IaaS resources can be back scaled down.

Recent trends in IaaS

Although it is useful to organize cloud services into its three different categories - SaaS, PaaS, and IaaS - the boundaries that separate the categories are fluid, especially considering the fact that PaaS and IaaS are relatively new. In a recent report for Gartner, Lydia Leong observes that IaaS is a “rapidly evolving market” and that “customer requirements and use cases...are diverse.” She further writes, “there is no ‘one size fits all’” model, which means that there is plenty of room for new vendors to enter the market as IaaS technology is further developed and refined.

Gartner has also drawn attention to the different “buyer constituencies” for the IaaS market: system administrators; application developers and engineers; and business buyers. Each of these segments has slightly different needs but because IaaS is relatively nascent, buyers are finding themselves settling for services that may not exactly meet their needs or fulfill their long-term IT goals. The diversity of buyer needs and the fact that IaaS is essentially provisioned like a utility means that vendors are becoming more attentive to distinguishing themselves from competitors by combining infrastructure resources with other value-added cloud services.

VMWare, for example, partnered with to create VMForce, a cloud platform for developing Java applications. With cloud integration increasingly becoming a mission-critical priority for enterprises, CloudHub, the world’s first iPaaS, provides developers with a platform for integrating applications across the enterprise and orchestrating services to create higher-level business applications without having to worry about setting up infrastructure hardware or installing special software.

Without a doubt, Infrastructure as a Service - and cloud computing in general - will continue to evolve in the years ahead, pushing IaaS vendors to further define and refine the space and tailor their services to meet changing enterprise needs in the new IT landscape.

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