IaaS
Infrastructure as a service (IaaS) is a cloud computing service model where a cloud services vendor provides computing resources such as storage, network, servers, and virtualization. This service frees users from maintaining their own data center, but they must install and maintain the operating system and application software. IaaS provides users with high-level APIs to control details of the underlying network infrastructure, such as backup, data partitioning, scaling, security, and physical computing resources. Services can be scaled on-demand by the user. According to the Internet Engineering Task Force (IETF), such infrastructure is the most basic cloud-service model. IaaS can be hosted in a public cloud, a private cloud, or a hybrid cloud.