Q11Cloud Computing

In the Infrastructure as a Service (IaaS) model, the cloud provider hosts the infrastructure components traditionally present in an on-premises data center, including servers, storage and networking hardware, as well as the virtualization or hypervisor layer. Users can deploy and run arbitrary software, including operating systems and applications. This offers high scalability and a pay-as-you-go billing model. Examples include Amazon Web Services (AWS) EC2, Google Compute Engine (GCE), and Microsoft Azure Virtual Machines.

Key Characteristics

• Resource Pooling: The provider maintains a large pool of physical hardware which is virtualized and allocated to tenants on demand, allowing multiple customers to share the same physical servers without interfering with each other.
• Self-Service Provisioning: Consumers can spin up virtual machines, attach storage volumes, and configure networks through a web console or API without any human interaction from the provider.
• Elastic Scaling: Compute and storage capacity can be increased or decreased within minutes to match workload demand, avoiding the need to purchase hardware for peak capacity that sits idle most of the time.
• Consumer Responsibility: The customer manages the operating system, middleware, runtime, and applications, while the provider manages the physical hardware, hypervisor, and networking below the virtual machine boundary.

Because IaaS shifts capital expenditure into operational expenditure, it is heavily used for hosting web applications, development and test environments, and big-data clusters where the required compute capacity fluctuates significantly over time. Compared to PaaS and SaaS, IaaS gives the consumer the deepest level of control, at the cost of requiring the consumer to handle OS patching, application deployment, and scaling logic themselves.