(1) See grid computing.|
(2) Using the Web server facilities of a third party provider on the Internet (the "cloud") to store, deploy and run applications. Cloud computing takes two forms. It may refer to "utility" computing in which only the hardware and software infrastructure (operating system, databases, etc.) are offered, or it may refer to "software as a service" (SaaS), which includes the business applications as well. Regardless whether the cloud is infrastructure only or includes applications, major features are self service, scalability and speed.
#1 - Do It Yourself
Customers log into the cloud and run their applications as desired. Although a representative of the cloud computing provider may be involved in setting up the service, customers make all subsequent configuration changes from their Web browsers. In most cases, everything is handled online from start to finish by the customer.
#2 - Scalability and Speed
The cloud provides virtually unlimited computing capacity and supports extra workloads on demand. In addition, cloud providers may be connected to multiple Tier 1 Internet backbones for fastest response times and availability.
Infrastructure and Applications (SaaS)
More often than not, cloud computing refers to application service providers (ASPs) that offer the whole ball of wax: the infrastructure as outlined below and the applications, relieving the organization of virtually all maintenance. Google Apps and Salesforce.com's CRM products are examples of this "software-as-a-service" model (SaaS), which is a paradigm shift because company data are stored externally. Even if data are duplicated inhouse, copies "in the cloud" create security and privacy issues.
In all its forms, cloud computing is considered the next great wave in IT and is currently a major buzzword.
Infrastructure Only (IaaS/PaaS)
Using the cloud for computing power only can be more economical than building new datacenters or renovating old ones to support new projects or seasonal increases. When constructing a datacenter, there are enormous security, environmental and management issues, not to mention hardware/software maintenance forever after. In addition, commercial cloud facilities may be able to withstand natural disasters that meet and exceed military standards.
Infrastructure-only cloud computing is also called "infrastructure as a service" (IaaS), "platform as a service" (PaaS), "cloud hosting," "utility computing," "grid hosting" and "grid computing."
For small Web developers and publishers, cloud providers such as Amazon and Google are invaluable (see EC2 and Google App Engine). Because cloud hardware can be configured to "dynamically scale" (expand on demand), a sudden increase in traffic can be handled by additional servers, such as immediately after launching a new product. Configuring servers inhouse to withstand bursts of traffic means computers run at lower capacity much of the time. Because cloud datacenters charge for actual usage, there is no wasted expense.
In addition, cloud datacenters employ automatic backup and recovery systems as well as utilize the latest virtualization techniques (see server virtualization). However, the way the cloud provides automatic processes differs. In some cases, they are entirely automatic. In others, the customer has to program and configure the cloud software to make them automatic.
Private and Hybrid Clouds
Enterprises also create private clouds within their own datacenters. Employing the same server virtualization techniques as the Internet clouds, the private cloud enjoys the same flexibility and self-service capabilities as the public cloud, but with greater control and privacy.
A hybrid cloud is using both private and public clouds. When new applications arise, or if the enterprise cloud is overloaded, the public cloud is used. Migrating virtualized applications from internal servers to the Internet and managing both venues from a central console are issues facing network administrators in 2010 and beyond. See personal cloud, SaaS, rich client, EC2, Google App Engine, Windows Azure, thin client, cloud, colocation, Open Cloud Manifesto and Web application.