cloud computing(redirected from on-demand computing)
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cloud computing,the delivery of shared computing resources over a network in a manner that makes accessing and configuring those resources convenient and largely independent of the use of a required location, device, and the like. Although paralleling in some ways the use of multiple terminals to access mainframe computers and client-server computer networks, cloud computing is distinguished from them by the relative ease of access to the computing resources, which may be shared by many individuals and organizations using a wide range of devices, and the relative ease with which these users may increase (or decrease) the type and volume of computing resources to which they have access. Cloud-computing resources, which include both hardware infrastructure, such as data storage, servers, and networks, as well as operating systems, computer programs, and services provided by such programs, are typically provided over the Internet by third-party companies.
Individuals, for example, may subscribe to services that allow them to use an Internet connection or a cellular phone network to upload and store files, whether documents, music, or pictures, on the services' computer servers. These files may then be accessed by the individual in another location on a different device, or the individual may permit others to access and download the files. Computers, tablets, and smartphones, using either web browers or specialized applications, can be used to access the files as long as they can establish a connection to the service's network. Internet music services, blogging and social-networking websites, and email services all provide direct consumer services using the resources of cloud computing.
Businesses may subscribe to a range of cloud-computing services, such as offsite data storage, hosting services for running web applications, an email service, or a suite of business applications. Cloud computing allows a company to readily increase or decrease the computing resources to which they have access based upon the company's changing needs. Costs may be reduced if a company pays only for the software and hardware resources that they need at a given time instead of making significant investments in computers, software, and support personnel that may be underutilized much of the time. Companies may have concerns about the security and privacy of their data when it is stored on a provider's servers, but in the case of smaller companies, a large provider of cloud-computing resources may be better equipped to provide security. Another cloud-computing concern is the possible interruption of a company's access to its applications and data, though this can be avoided to some degree through the establishment of appropriate redundancies. Some larger companies create so-called private clouds to provide computing resources from a common corporate pool to individual business units within the company, with the provision of these resources based on the changing needs of the business units.
cloud computingHardware and software services from a provider on the Internet (the "cloud"). Cloud providers replace inhouse operations and are invaluable for companies, no matter their size or applications. Cloud servers can be configured to handle tiny or huge amounts of traffic and expand or contract as needed.
Is Every Internet Function Cloud Computing?
Not really. Thousands of applications access a datacenter over the Internet behind the scenes for additional processing and updates, and although they obtain data from the cloud, that is not technically a cloud computing service. Cloud computing really came about when customers were able to open an account online, configure their needs and do their computing from a Web browser.
It all started with software as a service (SaaS), which offers specific applications online. Salesforce.com was notably one of the first. Secondly, Amazon, Google, Microsoft and other tech giants with years of experience running their own datacenters began to offer companies large and small an external alternative to inhouse operations. The combination of application services and general-purpose infrastructure caused cloud computing to flourish. See Amazon Web Services, Google App Engine and Windows Azure.
Cloud Computing Features
(Self Service) The customer (end user or IT professional) signs up online, activates and uses the hardware and software from start to finish without phoning a provider to set up an account. Of course, tech support is available if necessary.
(Scalability) Additional servers can be quickly configured to process more data or to handle a larger, temporary workload such as Web traffic over the holidays.
(Speed) Major cloud providers are connected to the Internet via multiple Tier 1 backbones for fast response times and fault tolerance.
SaaS (Software as a Service)
Starting in the late 1990s, SaaS providers offered an entire application to the end user online, eliminating all internal hardware and software maintenance. Myriad applications running from a Web browser use this model, including email, Google's G Suite and Salesforce.com's CRM. Customers pay by the number of users. For IT, this has been a paradigm shift. Although there are no more maintenance problems, there are security and privacy issues when company data are stored in the cloud.
IaaS (Infrastructure as a Service)
Also called "cloud hosting" and "utility computing," IaaS provides the basic hardware, which is typically a server and virtual machine (VM) environment. IaaS customers deploy their applications as well as their own "stack" of system software (database, language runtime engine and other system components). See virtual machine and technology stack.
PaaS (Platform as a Service)
PaaS includes the stack so that customers need only deploy their applications. With IaaS and PaaS, customers pay by some combination of server size, execution time, amount of sharing, storage and downloads. There are many options. See runtime engine and system software.
FaaS (Function as a Service)
At the most granular level, FaaS is the latest paradigm. Customers pay only for the time it takes to execute specific tasks (see serverless computing).
Datacenter Operation Is Major Work
Instead of operating its own servers, it can be more economical for a company to use the cloud and eliminate the security, maintenance, network and environmental issues with inhouse datacenters. In addition, commercial clouds may meet military standards for natural disasters.
The Virtualization Foundation
The cloud employs server virtualization, which, among other benefits, allows application workloads to be easily added and removed as self-contained modules. In fact, virtualization has been a major enabler of the cloud computing model. However, the amount of work required by the customer differs greatly. Configuring virtual implementations on servers can range from being almost entirely automatic to requiring that the IT administrator be thoroughly familiar with very technical software. See server virtualization and virtual machine.
Private and Hybrid Clouds
Enterprises can create private clouds in their datacenters that employ the same cloud computing infrastructure used on the Internet. The private cloud provides the same flexibility and self-service capabilities, but with complete control of privacy.
A hybrid cloud is both private and public. If the private cloud is overloaded, applications are activated on the Internet cloud. Extending software and databases from internal servers to a provider's servers and managing both venues from a central console are major issues in cloud computing administration. See fog computing, cloud management system, personal cloud, Windows Azure, thin client, cloud storage, colocation, Open Cloud Manifesto and Web application.