The cloud service model providing users with complete control over an underlying infrastructure is known as IaaS (Infrastructure as a Service). IaaS allows organizations to rent dedicated servers, storage, and networking components rather than investing in physical hardware. It offers flexibility and scalability, enabling users to deploy and manage virtual machines and other IT resources as needed. By leveraging IaaS, businesses can focus on development and application deployment while minimizing the complexities and costs associated with maintaining physical infrastructure. This model is particularly beneficial for organizations with fluctuating workloads.