What is Infrastructure as a Service? (IaaS)

IaaS provides and mantains the underlying hardware, operating system and network Infrastructure resources and provides it in a virtualiced, easy to manage comoditized way.  IaaS doesn’t care about the application at all.

IaaS is the base of the Cloud Computing paradigm, many people confuse CC with IaaS, thers just use the term Cloud Computing  when they are in fact talking about IaaS. IaaS has also been referred to as "Everything as a Service" and "Hardware as a Service".

IaaS offers CPU, memory, storage, networking and security as a package. IaaS is the virtual machine in the sky.

With IaaS, you can choose from a range of predefined virtual machines and load packaged operating system images  to it.

Well known and whidely trusted IaaS providers that offer services to the general public are: Amazon, Joyent, GoGrid and FlexiScale and Rackspace Cloud.

Amazon is probably the best known of the providers, Joyent is also huge and hosts some Facebook applications and the the social network LinkedIn, among others.

By moving your infrastructure to "the cloud", you have the ability to scale as if you owned your own hardware and data center (which is not realistic with a traditional hosting provider) but you keep the upfront costs to a minimum.

The hey benefits of IaaS:

Ability to scale on demand, instantly.

Per Hour billing, you only pay for what you use.

Ideal for startup business, where one of the most difficult things to do is keep capital expenditures under control.