Cloud computing

By Kamal Garg CSE

Meaning

Cloud computing refers to the delivery of computing and storage capacity[citation needed] as a service to a heterogeneous community of end-recipients. The name comes from the use of clouds as an abstraction for the complex infrastructure it contains in system diagrams. Cloud computing entrusts services with a user's data, software and computation over a network. It has considerable overlap with software as a service (SaaS).

End users access cloud based applications through a web browser or a light weight desktop or mobile app while the business software and data are stored on servers at a remote location. Proponents claim that cloud computing allows enterprises to get their applications up and running faster, with improved manageability and less maintenance, and enables IT to more rapidly adjust resources to meet fluctuating and unpredictable business demand. Cloud computing relies on sharing of resources to achieve coherence and economies of scale similar to a utility (like the electricity grid) over a network (typically the Internet). At the foundation of cloud computing is the broader concept of converged infrastructure and shared services.

History

The term cloud is used as a metaphor for the Internet, based on the cloud drawing used in the past to represent the telephone network, and later to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents. In the 1990s, telecommunications companies who previously offered primarily dedicated point-to-point data circuits, began offering virtual private network (VPN) services with comparable quality of service but at a much lower cost. By switching traffic to balance utilisation as they saw fit, they were able to utilise their overall network bandwidth more effectively. The cloud symbol was used to denote the demarcation point between that which was the responsibility of the provider and that which was the responsibility of the user. Cloud computing extends this boundary to cover servers as well as the network infrastructure. The underlying concept of cloud computing dates back to the 1960s, when John McCarthy opined that "computation may someday be organised as a public utility." Almost all the modern-day characteristics of cloud computing (elastic provision, provided as a utility, online, illusion of infinite supply), the comparison to the electricity industry and the use of public, private, government, and community forms, were thoroughly explored in Douglas Parkhill's 1966 book, The Challenge of the Computer Utility. Other scholars have shown that cloud computing's roots go all the way back to the 1950s when scientist Herb Grosch (the author of Grosch's law) postulated that the entire world would operate on dumb terminals powered by about 15 large data centers. An early but surprisingly complete implementation of cloud computing was implemented and patented (in Germany and England) by Hardy Schloer (which he termed the "one-page web")  with multiple user applications, multiple identification providers, cloud storage, back-end servers with plug-in applications, a multiple tiered server architecture able to handle different user devices over the internet, and built-in security features.

The ubiquitous availability of high capacity networks, low cost computers and storage devices as well as the widespread adoption ofhardware virtualization, service-oriented architecture, autonomic, and utility computing have led to a tremendous growth in cloud computing.

After the dot-com bubble, Amazon played a key role in the development of cloud computing by modernising their data centers, which, like most computer networks, were using as little as 10% of their capacity at any one time, just to leave room for occasional spikes. Having found that the new cloud architecture resulted in significant internal efficiency improvements whereby small, fast-moving "two-pizza teams" could add new features faster and more easily, Amazon initiated a new product development effort to provide cloud computing to external customers, and launched Amazon Web Service (AWS) on a utility computing basis in 2006. In early 2008, Eucalyptus became the first open-source, AWS API-compatible platform for deploying private clouds. In early 2008,OpenNebula, enhanced in the RESERVOIR European Commission-funded project, became the first open-source software for deploying private and hybrid clouds, and for the federation of clouds. In the same year, efforts were focused on providing quality of serviceguarantees (as required by real-time interactive applications) to cloud-based infrastructures, in the framework of the IRMOS European Commission-funded project, resulting to a real-time cloud environment. By mid-2008, Gartner saw an opportunity for cloud computing "to shape the relationship among consumers of IT services, those who use IT services and those who sell them" and observed that "[o]rganisations are switching from company-owned hardware and software assets to per-use service-based models" so that the "projected shift to computing... will result in dramatic growth in IT products in some areas and significant reductions in other areas." In 2012, Dr. Biju John and Dr. Souheil Khaddaj incorporated the semantic term into the cloud "Cloud computing is a universal collection of data which extends over the internet in the form of resources (such as information hardware, various platforms, services etc.) and forms individual units within the virtualization environment. Held together by infrastructure providers, service providers and the consumer, then it is semantically accessed by various users." (CLUSE 2012), Bangalore, April 2012

Characteristics

Cloud computing exhibits the following key characteristics:

         Agility improves with users' ability to re-provision technological infrastructure resources.

         Application programming interface (API) accessibility to software that enables machines to interact with cloud software in the same way the user interface facilitates interaction between humans and computers. Cloud computing systems typically use REST-based APIs.

         Cost is claimed to be reduced and in a public cloud delivery model capital expenditure is converted to operational expenditure. This is purported to lower barriers to entry, as infrastructure is typically provided by a third-party and does not need to be purchased for one-time or infrequent intensive computing tasks. Pricing on a utility computing basis is fine-grained with usage-based options and fewer IT skills are required for implementation (in-house). The e-FISCAL project's state of the art repository contains several articles looking into cost aspects in more detail, most of them concluding that costs savings depend on the type of activities supported and the type of infrastructure available in-house.

         Device and location independence enable users to access systems using a web browser regardless of their location or what device they are using (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.

         Virtualization technology allows servers and storage devices to be shared and utilization be increased. Applications can be easily migrated from one physical server to another.

         Multitenancy enables sharing of resources and costs across a large pool of users thus allowing for:

         Centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.)

         Peak-load capacity increases (users need not engineer for highest possible load-levels)

         Utilisation and efficiency improvements for systems that are often only 10–20% utilised.

         Reliability is improved if multiple redundant sites are used, which makes well-designed cloud computing suitable for business continuity and disaster recovery.

         Scalability and Elasticity via dynamic ("on-demand") provisioning of resources on a fine-grained, self-service basis near real-time, without users having to engineer for peak loads.

         Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.

         Security could improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels. Security is often as good as or better than other traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford. However, the complexity of security is greatly increased when data is distributed over a wider area or greater number of devices and in multi-tenant systems that are being shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security.

         Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer and can be accessed from different places.

Relevance in today’s life

Many universities, vendors and government organizations are investing in research around the topic of cloud computing:

         In October 2007, the Academic Cloud Computing Initiative (ACCI) was announced as a multi-university project designed to enhance students' technical knowledge to address the challenges of cloud computing. In April 2009, UC Santa Barbara released the first open source platform-as-a-service, AppScale, which is capable of running Google App Engine applications at scale on a multitude of infrastructures.

         In April 2009, the St Andrews Cloud Computing Co-laboratory was launched, focusing on research in the important new area of cloud computing. Unique in the UK, StACC aims to become an international centre of excellence for research and teaching in cloud computing and will provide advice and information to businesses interested in using cloud-based services

         In October 2010, the TClouds (Trustworthy Clouds) project was started, funded by the European Commission's 7th Framework Programme. The project's goal is to research and inspect the legal foundation and architectural design to build a resilient and trustworthy cloud-of-cloud infrastructure on top of that. The project also develops a prototype to demonstrate its results.

         In December 2010, the TrustCloud research project  was started by HP Labs Singapore to address transparency and accountability of cloud computing via detective, data-centric approaches  encapsulated in a five-layer TrustCloud Framework. The team identified the need for monitoring data life cycles and transfers in the cloud, leading to the tackling of key cloud computing security issues such as cloud data leakages, cloud accountability and cross-national data transfers in transnational clouds.

         In July 2011, the High Performance Computing Cloud (HPCCLoud) project was kicked-off aiming at finding out the possibilities of enhancing performance on cloud environments while running the scientific applications - development of HPCCLoud Performance Analysis Toolkit which was funded by CIM-Returning Experts Programme - under the coordination of Prof. Dr. Shajulin Benedict.

         In June 2011, the Telecommunications Industry Association developed a Cloud Computing White Paper, to analyze the integration challenges and opportunities between cloud services and traditional U.S. telecommunications standards.

Advantages

There are many possible advantages of cloud computing, but they may not apply to all consumers.

Reduced costs

Cloud services paid for on a usage basis can be financially advantageous for a consumer when compared to the outright purchase, or long-term rental, of what would be a big-budget item. Also, there are reduced operating costs, because a cloud consumer does not need to house, staff and maintain their own equipment.

Up-to-date software

SaaS consumers can always have the most up-to-date software, because versioning is controlled centrally by the cloud provider, and when they make a new release it is automatically available to every user.

This is particularly advantageous for cloud desktops, because deployment of new software versions can be very costly and time consuming for a large organisation with many PCs, and because it can therefore be difficult to ensure that everyone has the same version of the organisation's PC software applications at any one time.

Improved access

Cloud computing involves using the Internet, and this can provide access from multiple locations and many different types of user device.

Sharing and co-operation

Cloud services are advantageous, when compared to PCs and local servers, for activities that require co-operation among distributed groups.

Flexible and infinite scaling

Flexible and infinite scaling can be an advantageous feature of cloud-computing services, for example to allow for a sudden increase in demand by the users. This has traditionally been a difficulty for fully owned and self-managed IT resources, where there can be, for example, one server with a given, fixed size, and where some of its capacity may be wasted when demand is low, but where it may be overloaded, resulting in slow response times, when demand is high.

Simpler capacity planning

Cloud computing moves the IT capacity-planning role from the consumer to the cloud provider, and they can be in a better position to optimize the cloud resources used by their consumers than the consumers themselves would be for their own resources.

For example, the provider may be able to supply better demand smoothing, because they can perform capacity planning over a much larger pool of resources, and for a large group of consumers, whose peak loads will probably not occur all at the same time.

Risks

Besides the advantages of cloud computing, there are also risks, at least for some consumers.