Cloud computing is the on-demand delivery of IT resources—applications, storage, databases, networking and more—over the Internet (“the cloud”). Many popular online services, from email and video streaming to file storage, travel booking and banking, use cloud computing. It provides anytime/anywhere access to servers, files, images, documents and application services from any device with an Internet browser. Cloud computing can also protect business continuity by hosting IT resources off site. Cloud service providers (such as Amazon Web Services, Microsoft Azure and Google Cloud Platform) offer cloud computing on a pay-as-you-go basis. Similar to the utility company model, clients only pay for the services they use.
Most cloud computing services fall into three categories: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS). IaaS allows businesses to essentially rent their IT infrastructure from a cloud provider. PaaS supplies an on-demand environment for software development. SaaS delivers applications over the Internet. Businesses of all sizes use cloud computing to reduce hardware, software and IT maintenance costs. Cloud computing can also increase business agility and solve IT capacity problems by providing instant up-or-down scalability and allowing IT resources to be provisioned and relinquished as needed.
Cloud computing services may be deployed in a public cloud, a private cloud or a hybrid cloud. Public cloud services are owned and managed by a cloud provider and used by many different organizations. Private cloud services are owned and used exclusively by a single organization and usually physically located in their on-site data center. Some companies pay third-party service providers to host a private cloud for them. Hybrid cloud services, also called multi- or mixed-cloud services, combine public and private clouds to serve different needs in an organization.
The largest cloud computing infrastructures in the world, including Amazon Web Services and Google Cloud Platform, run on Linux.