Cloud computing
Cloud computing is the on-demand availability of computer system resources, especially data storage and computing power, without direct active management by the user. The term is generally used to describe data centers available to many users over the Internet.
Cloud computing relies on sharing resources to achieve coherence and economies of scale. Users can access applications, services, and data hosted on remote servers provided by a cloud provider, rather than managing the underlying hardware and software themselves. It is often offered on a pay-per-use basis.
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Overview
Cloud computing shifts the burden of owning, operating, and maintaining IT infrastructure (like servers, storage systems, networking equipment) from the individual user or organization to a third-party provider. Users access these resources typically through a web browser or dedicated client software over the Internet.
Key characteristics include:
- **On-demand self-service:** Users can provision computing capabilities, such as server time and network storage, as needed automatically, without requiring human interaction with each service provider.
- **Broad network access:** Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous client platforms (e.g., mobile phones, laptops, PDAs).
- **Resource pooling:** The provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand.
- **Rapid elasticity:** Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.
- **Measured service:** Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service. Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.
Service Models
Cloud providers offer services at different levels of the IT stack. The most common service models are:
- Infrastructure as a Service (IaaS)
- The provider offers virtualized computing hardware resources over the internet, such as virtual machines, storage, and networking. The user is responsible for installing and managing the operating systems, applications, and middleware.
- Platform as a Service (PaaS)
- The provider offers hardware and a software platform, typically including an operating system, database, and web server. This allows customers to develop, run, and manage applications without the complexity of building and maintaining the underlying infrastructure.
- Software as a Service (SaaS)
- The provider offers complete software applications over the internet, accessible via a web browser or client application. The user only interacts with the software; the provider manages the underlying infrastructure, operating system, and application maintenance.
Deployment Models
Cloud infrastructure can be deployed and managed in different ways:
- Public cloud
- The cloud infrastructure is owned and operated by a third-party cloud provider and shared among multiple customers (tenants) over the public internet. Examples include Amazon Web Services (AWS), Google Cloud Platform (GCP), and Microsoft Azure.
- Private cloud
- The cloud infrastructure is dedicated to a single organization. It may be managed by the organization itself or by a third party. It can be physically located on the organization's premises or off-site.
- Hybrid cloud
- A combination of public and private clouds that remain distinct but are linked together, allowing data and applications to be shared between them. This allows organizations to leverage the benefits of both models.
Benefits
Cloud computing offers numerous potential benefits:
- Cost Savings: Reduces capital expenditures on hardware and infrastructure. Often shifts costs to operational expenses with pay-per-use models.
- Scalability and Elasticity: Easily scale resources up or down based on demand, avoiding over-provisioning.
- Reliability: Providers often have distributed infrastructure, reducing the risk of downtime compared to single on-premises systems.
- Accessibility: Access services and data from anywhere with an internet connection.
- Faster Deployment: Quickly provision resources and deploy applications compared to traditional methods.
- Simplified IT Management: Reduces the need for in-house IT staff to manage physical hardware and low-level software.
- Collaboration: Facilitates collaboration through shared applications and data.
History
The concepts behind cloud computing, such as utility computing and time-sharing, date back to the 1960s. However, the modern era of cloud computing began to take shape with the rise of the Internet, virtualization technologies, and increasing network bandwidth in the late 1990s and early 2000s.
Early developments included Application Service Providers (ASPs) offering software over the web. The launch of Amazon Elastic Compute Cloud (EC2) in 2006 and Amazon Simple Storage Service (S3) in 2006 are widely considered milestones that popularized the IaaS model and helped define the modern understanding of cloud computing. Other major technology companies soon followed, leading to the rapid growth of the cloud industry.
See also
- Virtualization
- Data center
- Pay-as-you-go
- On-demand computing
- Infrastructure as a Service
- Platform as a Service
- Software as a Service
- Public cloud
- Private cloud
- Hybrid cloud
