IaaS (Infrastructure-as-a-Service) basically means that you don’t have to care about hardware. It is a ground floor for any cloud. It allows to forget about particular hardware and only specify 1) number of CPU cores 2) number of GB of RAM 3) number of GB of disk space. It may also allow to perform some configuration of network interfaces.
IaaS allows to install a guest operating system to a virtual server and access this operating system remotely.
Examples of IaaS:
- Amazon EC2
- Red Hat Cloud Infrastructure & OpenStack
- VMware vSphere
- Citrix XEN Server
- Microsoft Azure
- Almost any VPS hosting
The major advantage of IaaS is that all the guest operating systems in a cloud are running on absolutely similar virtual hardware and their images could be cloned from one virtual server to another.