CloudComputing

Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (such as networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort. It enables a pay-as-you-go or subscription-based approach and supports scalable, elastic resource use. Cloud services are typically provided remotely by providers and accessed via the internet or private networks.

IaaS provides virtualized computing resources over the internet (virtual machines, storage, and networking). PaaS offers a platform that developers can use to build, deploy, and manage applications without managing underlying infrastructure. SaaS delivers software applications hosted on the provider's cloud and accessed via a client interface.

Public cloud is open to many customers; private cloud is dedicated to a single organization; hybrid combines multiple models; community cloud is shared by a specific community.

Characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity, measured service.

Architecture and considerations: It relies on virtualization, multi-tenancy, APIs, automation and data centers; security and governance concerns, data privacy, compliance, data location, latency, vendor lock-in, service-level agreements; risk of outages.

History and adoption: Origins trace to early computing concepts and mainframe resource sharing; modern cloud computing grew from advances in virtualization, grid computing, and service-oriented architectures. Large providers launched public cloud offerings in the mid-2000s, such as Amazon Web Services EC2 (2006) and later Google Cloud and Microsoft Azure, which accelerated adoption.