Infrastructure-as-a-Service (IaaS)
Infrastructure-as-a-Service (IaaS) is a fundamental Cloud-Computing delivery model that provides virtualized computing resources over the internet. In this model, a third-party provider hosts Servers, Storage, and Networking components on behalf of its users. Major global providers include Amazon-Web-Services, Microsoft-Azure, and Google-Cloud-Platform. This service model allows for high Scalability and significantly reduces the need for upfront Capital-Expenditure.
According to Gartner, IaaS is a highly automated offering where compute resources are owned and hosted by a service provider and offered to customers on-demand. Users typically interact with these resources using Application-Programming-Interfaces or web-based consoles. The Virtualization layer is the core technology that enables the creation of multiple Virtual-Machines on physical hardware. For further technical insights, see the IBM guide to IaaS.
Security within the IaaS framework is typically managed through a Shared-Responsibility-Model, where the provider secures the physical infrastructure and the Hypervisor, while the customer is responsible for the Operating-System, applications, and data. This structural division is a critical component of modern Cloud-Security. Organizations like NIST provide standardized frameworks to help categorize these cloud services.