Cloud infrastructure is a comprehensive term used to describe the various hardware and software components that are used to deliver cloud computing services. The components are offered as virtual infrastructure and delivered to the end users in the form of Infrastructure as a Service (IaaS) via a network or over internet. The virtual components include virtual servers, memory, PCs, network routers, switches, firewalls, storage and virtual software. Cloud infrastructure is available in the other two models of cloud computing - Software as a Service (SaaS) and Platform as a Service (PaaS). The three models are referred as cloud computing stack with IaaS as the basic foundation, PaaS as middle layer and SaaS as top layer. There are several benefits of cloud infrastructure for all types of businesses. Users do not have to invest on any infrastructure. They draw the services they require and pay for the services they consume usually on an hourly, weekly or monthly basis depending on usage. It becomes more affordable as it removes the general practice of paying the service provider a set price. Cloud infrastructure that is maintained by the providers is offered as public cloud and at times when the business maintains it is called as private cloud. The third model called hybrid cloud is maintained by both the user and the vendor.