IaaS

Infrastructure as a Service (IaaS) is a form of cloud computing that provides virtualized computing resources over the internet. In an IaaS model, a cloud provider hosts core infrastructure components such as servers, storage, and networking hardware, together with virtualization and a management layer. Customers rent these resources on a pay-as-you-go basis and scale them dynamically as needs change.

Users are typically responsible for managing operating systems, middleware, runtime environments, applications, and data. The provider handles the underlying physical hardware, virtualization, and often the load balancers, firewalls, and other basic networking elements configured via an API or portal.

Common deployment models include public cloud, private cloud, hybrid cloud, and community cloud. Resources are allocated as virtual machines, storage volumes, and virtual networks; pricing is based on usage, provisioned capacity, and service levels.

Typical use cases include development and testing environments, hosting of websites and applications, disaster recovery, scalable batch processing, and workloads requiring variable capacity.

Advantages of IaaS include cost efficiency by eliminating capital expenditure, rapid provisioning, elasticity, and the ability to focus on applications rather than hardware management. Limitations include reduced control over infrastructure, potential security and compliance challenges, reliance on internet connectivity, and the risk of vendor lock-in.

Security and compliance are shared between provider and customer; providers typically secure physical facilities, network virtualization, and hypervisors, while customers manage data protection, access controls, identity management, and application security.

Management is often achieved via APIs, web consoles, and orchestration tools; infrastructure as code (IaC) enables automated provisioning using tools such as Terraform or CloudFormation. IaaS is typically contrasted with Platform as a Service (PaaS) and Software as a Service (SaaS).

Major IaaS providers include Amazon Web Services (EC2 and related services), Microsoft Azure (Virtual Machines), and Google Cloud Platform (Compute Engine), along with other vendors offering competing services.