Infrastructure as a Service (IaaS) is the most flexible cloud service where clients have direct access to their servers and storage. In the case of IaaS, the computing resources provided are virtualised hardware or a computing infrastructure. Instead of purchasing hardware outright, users pay for IaaS on demand. IaaS data is on the cloud, therefore there is no single point of failure.
Three types of IaaS Cloud offerings
Public IaaS Cloud: In the public cloud, providers rent out hardware resources in a multi-tenant method to the general public using virtualisation technology. This allows multiple users to share server resources. Easy to set up, highly scalable and elastic, where users will only pay for the resources that they use.
Private IaaS Cloud: The private cloud employs virtualisation technology and delivers cloud-computing services to a single organisation. The services are provisioned privately and sit behind the firewalls managed by the individual business. Servers and resources are specifically dedicated to the individual business, and cannot be used by others.
Hybrid IaaS Cloud: A hybrid cloud is generally considered the conjoining of physical and virtual infrastructure in a public or private cloud. For example, a company may opt to manage some physical servers in a private cloud, while outsourcing other servers to a public cloud. The hybrid cloud allows companies to take advantage of scalability with cloud technologies, all while managing sensitive company data or applications not suitable or licensable in the cloud.