Cloud computing is a way of delivering shared, flexible and scalable information technology or IT services through non – firmly allocated information technology resources over a network. Typical characteristics of cloud hosting or cloud computing technology are real time, metered delivery as a self service on the basis of internet technologies charged according to use. Cloud computing technology thus enables users to reallocate investment expenditure to operating expenses. The information technology or IT services can cover applications, application development and operating platforms and basic infrastructure.
Basically, cloud computing takes the idea of information technology outsourcing a step further. The intention of cloud hosting or cloud computing technology is to enable users to concentrate on their core competencies, and leave out peripheral parts of their operations to specialized service providers. Cloud hosting service providers highlight the main features of this technology as the ability to make processing capacity and software available, for a charge, via the World Wide Web whatever the user’s location and equipment, and that they can rapidly adapt their services to requirements. Cloud computing service providers often like to represent these offers under the heading – the Internet of services. Users of cloud services are motivated chiefly by considerations of reducing their information technology or IT capacities, which are designed for the few moments of peak demand, and of converting some of this fixed expenditure into variable costs. Businesses’ customary aim with cloud hosting is to cut costs. Businesses that outsource IT capabilities reduce their capital formation and the need for internal IT specialists. In principle, cloud computing leads to more economical use of the resources available, and also makes it possible to convert fixed expenditure on capital and labor into variable costs, with capital costs usually proving quicker to convert into variable costs than labor costs.
Depending on their deployment model, cloud computing services are divided as follows into the two pure forms Public Cloud and Private Cloud and a composite form, the Hybrid Cloud. In the case of a public cloud IT resources or software are provided by an external supplier via the World Wide Web. Users’ data and applications are all located on the same physical infrastructure but with separate individual allocation. In this instance several users therefore share the cloud infrastructure. With a private cloud IT resources or software are customized to the requirements of a single user and provided exclusively to that user by an external provider or even from within the user company. In this case one single user therefore has exclusive use of the special cloud infrastructure. The distinction between this and traditional hosting is somewhat blurred. Between the two pure play public and private cloud forms there exists a wide variety of different mixed cloud computing types known as hybrid cloud. The various hybrid cloud services aim to combine the advantages of public and private cloud for their respective intended environments.
Cloud Computing provisioning is categorized as follows according to the service models used to provide capability to the outsourcing user. With infrastructure as a service (IaaS) the cloud provisions such basic IT infrastructure as storage, network and computing capacity. With platform as a service (PaaS) the cloud provisions higher infrastructure level services for the consumer. In both a runtime environment (RTE) and an integrated development environment (or IDE) the cloud enables users to configure differentiated applications for their own individual needs. With software as a service (SaaS), software is provided as an integrated service network based on the cloud infrastructure. Consequently users save the costs of hardware and software licenses and maintenance of the IT infrastructure.