Cloud Computing 2

 

Cloud computing From Wikipedia, the free encyclopedia be merged  merged into this article or section. It has been suggested that  that  Cloud computing security  be  Discuss)) Proposed since December 2011.  (Discuss

Cloud computing logical diagram

computing  as a  a service  service rather than a  a product product,, whereby shared Cloud computing is the delivery of  of computing resources, software, and information are provided to computers and other devices as a a network network((typically the  the Internet Internet)).[1]  metered  service  metered service over a  Computing clouds provide computation, software, data access, and storage resources without requiring cloud users to know the location and other details of the computing infrastructure. Within limits, cloud users can consume any amount of these resources without having first to acquire servers or other computing equipment. A parallel to this concept can be drawn with the  electricity grid, grid, wherein end-users consume power without needing to understand the component devices or infrastructure required to provide the service. a web browser browser  or a light weight desktop or or  mobile End users access cloud based  based  applications  applications through a  appwhile while the business  business software  software and data are stored on  on servers  servers at a remote location. Cloud application app providers strive to give the same or better service and performance as if the software programs were installed locally on end-user computers. In some cases, legacy applications (line of business applications

 

that until now have been prevalent in thin client Windows computing) are delivered via a screen-sharing centre  location; in other technology, while the computing resources are consolidated at a remote  remote  data centre cases, entire business applications have been coded using web-based technologies such as  as  AJAX. AJAX.  At the foundation of cloud computing is the broader concept of infrastructure convergence (or  (or Converged [2]

Infrastructure)) and  and shared services services..  This type of data centre environment allows enterprises to get their Infrastructure applications up and running faster, with easier manageability and less maintenance, and enables IT to more rapidly adjust IT resources (such as servers, storage, and networking) to meet fluctuating and a nd [3][4]

meet service-level unpredictable business demand. demand.[3][4] Commercial offerings may be required to meet  [5][6]

agreements  (SLAs), but specific terms are less often negotiated by smaller companies companies..[5][6]  agreements Contents

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1 Comparison  Comparison  2 Characteristics  Characteristics  History  3 History  Layers   4 Layers

  4.1 Client Client  

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  4.2 Application  Application 

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  4.3 Platform  Platform 

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  4.4 Infrastructure  Infrastructure 

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  4.5 Server Server  

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models  5 Deployment models 

  5.1 Public cloud  cloud 

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  5.2 Community cloud  cloud 

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  5.3 Hybrid cloud  cloud  

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  5.4 Private cloud  cloud 

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6 Architecture  Architecture 

  6.1 The Intercloud  Intercloud 

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  6.2 Cloud engineering  engineering 

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7 Issues  Issues 

  7.1 Privacy Privacy  

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  7.2 Compliance Compliance  

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  7.3 Legal  Legal 

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  7.4 Open source  source 

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standards     7.5 Open standards

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  7.6 Security  Security 

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  7.7 Sustainability  Sustainability 

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Abuse     7.8 Abuse

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8 Research Research   9 See also  also  References  10 References  11 External links  links 

edit]]Comparison [edit Cloud computing shares characteristics with: [7]

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Autonomic computing  of  self-management. self-management.[7]  computing — Computer systems capable of 

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Client –  –server model  model — Client  –server computing refers computing refers broadly to any  any distributed application  application that [8]

distinguishes between service providers (servers) and service requesters (clients). (clients) .[8]  

 

Grid computing  of distributed distributed  and  and parallel computing, computing, whereby a 'super and virtual computing — "A form of  cluster  of networked,  networked, loosely coupled  coupled computers acting in concert to computer' is composed of a  a cluster perform very large tasks."

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Mainframe computer  computer — Powerful computers used mainly by large organisations for critical census,, industry and consumer statistics, police applications, typically bulk data processing such as  as  census planning,, and financial financial  transaction processing processing..[9]  and secret intelligence services,  services, enterprise resource planning

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Utility computing  of computing resources, resources, such as computation and storage, as a computing — The "packaging of  [10][11]

metered service similar to a traditional public utility, such as electricity." electricity. "[10][11]  

 

Peer-to-peer  Peer-to-peer — Distributed architecture without the need for central coordination, with participants being at the same time both suppliers and consumers of resources (in contrast to the traditional client – server model).

[edit] edit]Characteristics Cloud computing exhibits the following key characteristics:

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Empowerment  of end-users of computing resources by putting the provisioning of those resources in Empowerment their own control, as opposed to the control of a centralized IT service (for example)

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

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Application programming interface  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 REST--based APIs. computers. Cloud computing systems typically use  use  REST

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Cost  model  capital expenditure  expenditure is converted Cost is claimed to be reduced and in a public cloud delivery model  [12]

expenditure.. to to  operational expenditure

 This is purported to lower  lower barriers to entry entry,, as infrastructure is typically

provided by a third-party and does not need to be purchased for one-time or infrequent intensive

 

computing  basis is fine-grained with usage-based options and computing tasks. Pricing on a  a  utility computing [13]

fewer IT skills are required for implementation (in-house). (in-house) .[13]  

 

Device  independence[14] enable users to access systems using a web browser Device and location independence 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 [13]

anywhere.. anywhere 

 

 

Virtualization  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.

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Multi-tenancy  Multi-tenancy 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. utilised.

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[15]

Reliability  Reliability is improved if multiple redundant sites are used, which makes well-designed cloud [16]

continuity  and  and disaster recovery recovery.. computing suitable for  for business continuity 

 

 

 

Scalability  ("on-demand") provisioning provisioning  of resources on a fine-grained, selfScalability and Elasticity via dynamic ("on-demand")  [17][18]

service basis near real-time, without users having to engineer for peak loads .[17][18]  

 

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

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[13]

 

Security  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 [19]

stored kernels. kernels.[19] 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 [20]

afford.[20] However, the complexity of security is greatly increased when data is distributed over a wider afford. area or greater number of devices and in multi-tenant systems that are being shared by unrelated logs  may be difficult or impossible. Private cloud users. In addition, user access to security  security  audit logs installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security. 

 

Maintenance  Maintenance of cloud computing applications is easier, because they do not need to be installed on each user's computer.

edit]]History [edit The term "cloud" is used as a metaphor for the Internet, based on the cloud drawing used in the past to [21]

in  computer network diagrams diagrams  as represent the telephone network, network,[21] and later to depict the Internet in  abstraction  of the underlying infrastructure it represents. represents . an an  abstraction

[22]

 

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

[23] [24][25]

 

 Details are abstracted from end-users, who no

 

longer have need for expertise in, or control over, the technology infrastructure "in the cloud" that supports them. McCarthy  opined that The underlying concept of cloud computing dates back to the 1960s, when  John McCarthy "computation may someday be organised as a  a  public utility. 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 Parkhill''s 1966 book, The Challenge of the Computer Utility . Other scholars have explored in  in Douglas Parkhill shown that cloud computing's roots go all the way back to the 1950s when s scientist cientist  Herb Grosch  Grosch (the author of  of Grosch's law law)) postulated that the entire world would operate on dumb terminals powered by about [26]

15 large data centers. centers.[26]  telephony  in that telecommunications companies, who until the 1990s The actual term "cloud" borrows from  from  telephony Network  (VPN) offered primarily dedicated point-to-point data circuits, began offering  offering Virtual Private Network 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 respons ibility of the user. Cloud computing c omputing extends this boundary to cover servers as well as the network infrastructure. infrastructure.[27]  Amazon  played a key role in the development of cloud computing by modernising After the  the dot-com bubble, bubble, Amazon their  data centers, their centers, which, like most  most computer networks, networks, were using as little as 10% of their capacity at any one time, just to leave room for occasional occas ional 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 a  utility computing computing  basis in computing to external customers, and launched  launched  Amazon Web Service (AWS)  (AWS) on a [15][28]

2006.[15][28]  2006. In early 2008,  2008, Eucalyptus  Eucalyptus became the first open-source, AWS API-compatible platform for deploying private clouds. In early 2008,  2008, OpenNebula, OpenNebula, enhanced in the RESERVOIR European Commission-funded project, became the first open-source software for deploying private and hybrid clouds, and for the [29]

federation of clouds. clouds.

 In the same year, efforts were focused on providing QoS guarantees (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. environment.[30] By mid-2008, Gartner saw an opportunity for cloud computing "to shape the relationship among consumers of IT [31]

services, those who use IT services and those who sell them" them"[31] 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 cloud computing ... will result in dramatic growth in IT products in some areas and [32]

significant reductions in other areas." areas. "[32] 

edit]]Layers [edit

 

Once an internet protocol connection is established among several computers, it is possible to share services within any one of the following layers.

edit]]Client [edit See also:  Category:Cloud clients   of computer hardware  hardware and/or  and/or computer software software  that relies on cloud computing for A cloud client  consists of  application delivery and that is in essence useless without it. Examples include some computers Chromebooks)), phones (example:  (example: Google Nexus Nexus  series) and other devices, devices,  operating (example:  Chromebooks (example: [33][34][35] systems  (example:  (example: Google Chrome OS OS)), and  and browsers. browsers.[33][34][35]   systems

edit]]Application [edit See also:  Category:Cloud applications   Cloud application services or "Software as a Service  Service (SaaS)" deliver software as a service over the Internet, eliminating the need to install and run the application on the customer's own computers and simplifying maintenance and support. A cloud application  application is software provided as a service. It consists of the following: a package of interrelated tasks, the definition of these tasks, and the configuration files, which contain dynamic information about tasks at run-time. Cloud tasks provide compute, storage, communication c ommunication and management capabilities. Tasks can be cloned into multiple virtual machines, and are accessible through application programmable of utility computing  computing that can scale out and in to match the interfaces (API) API). Cloud applications are a kind of  workload demand. Cloud applications have a pricing model that is based on different compute and storage usage, and tenancy metrics. metrics.

[36]

 

elasticity.. Cloud applications have What makes a cloud application different from other applications is its  elasticity the ability to scale out and in. This can be achieved by cloning tasks in to multiple  virtual machines  machines at runtime to meet the changing work demand. Configuration Data is where dynamic aspects of cloud application