CloudComputingDEF: Cloud Computing is a virtualizedcompute power and storage delivered viaplatform-agnostic infrastructures ofabstracted hardware and softwareaccessed over the Internet. These shared,on-demand IT resources, are created anddisposed of efficiently, are dynamicallyscalable through a variety ofprogrammatic interfaces and are billedvariably based on measurable usage.Cloud computing is a general term foranything that involves delivering hostedservices over the Internet. These servicesare broadly divided into three categories:Infrastructure-as-a-Service (IaaS),Platform-as-a-Service (PaaS) andSoftware-as-a-Service (SaaS). The namecloud computing was inspired by thecloud symbol thats often used torepresent the Internet in flowcharts anddiagramsA cloud can be private or public. Apublic cloud sells services to anyone onthe Internet. (Currently, Amazon WebServices is the largest public cloudprovider.) A private cloud is aproprietary network or a data center thatsupplies hosted services to a limitednumber of people. When a serviceprovider uses public cloud resources tocreate their private cloud, the result iscalled a virtual private cloud. Private orpublic, the goal of cloud computing is toprovide easy, scalable access tocomputing resources and IT services.Infrastructure-as-a-Service like AmazonWeb Services provides virtual serverinstanceAPI) to start, stop, access andconfigure their virtual servers andstorage. In the enterprise, cloudcomputing allows a company to pay foronly as much capacity as is needed, andbring more online as soon as required.Because this pay-for-what-you-usemodel resembles the way electricity, fueland water are consumed, its sometimesreferred to as utility computing.Platform-as-a-service in the cloud isdefined as a set of software and productdevelopment tools hosted on theproviders infrastructure. Developerscreate applications on the providersplatform over the Internet. PaaSproviders may use APIs, website portalsor gateway software installed on thecustomers computer. Force.com, (anoutgrowth of Salesforce.com) andGoogleApps are examples of PaaS.Developers need to know that currently,there are not standards forinteroperability or data portability in thecloud. Some providers will not allowsoftware created by their customers to bemoved off the providers platform.In the software-as-a-service cloudmodel, the vendor supplies the hardwareinfrastructure, the software product andinteracts with the user through a front-end portal. SaaS is a very broad market.Services can be anything from Web-based email to inventory control anddatabase processing. Because the serviceprovider hosts both the application andthe data, the end user is free to use theservice from anywhere.Types:
Public Cloud: Computinginfrastructure is hosted at thevendor’s premises. The customerhas no visibility over the locationof the cloud computinginfrastructure. The computinginfrastructure is shared betweenorganizations.Private Cloud:Computing architecture isdedicated to the customer and isnot shared with otherorganisations. They areexpensive and are consideredmore secure than Public Clouds.Private clouds may be externallyhosted ones as well as in premisehosted clouds.diagram is available under aCreative Commons AttributionShareAlike 3.0 license in PNGand SVG formats from theWikimedia Commons (Cloudcomputing types.svgHybrid Cloud: Organisationshost some critical, secureapplications in private clouds.The not so critical applicationsare hosted in the public cloud.The combination is known asHybrid Cloud. Cloud bursting isthe term used to define a systemwhere the organisation uses itsown infrastructure for normalusage, but cloud is used for peakloads.Community Cloud: Thecloud infrastructure is sharedbetween the organizations of thesame community. For example,all the government agencies in acity can share the same cloud butnot the non government agencies.LayersOnce an internet protocol connection isestablished among several computers, itis possible to share services within anyone of the following layers.ClientSee also: Category:Cloud clientsA cloud client consists of computerhardware and/or computer software thatrelies on cloud computing forapplication delivery and that is inessence useless without it. Examplesinclude some computers (example:Chromebooks), phones (example:Google Nexus series) and other devices,
operating systems (example: GoogleChrome OS), and browsers.ApplicationSee also: Category:Cloud applicationsCloud application services or "Softwareas a Service (SaaS)" deliver software asa service over the Internet, eliminatingthe need to install and run theapplication on the customers owncomputers and simplifying maintenanceand support.PlatformSee also: Category:Cloud platformsCloud platform services, also known asplatform as a service (PaaS), deliver acomputing platform and/or solutionstack as a service, often consumingcloud infrastructure and sustaining cloudapplications.It facilitates deploymentof applications without the cost andcomplexity of buying and managing theunderlying hardware and softwarelayers.Cloud computing isbecoming a major change in ourindustry, and one of the most importantparts of this change is the shift of cloudplatforms. Platforms let developers writecertain applications that can run in thecloud, or even use services provided bythe cloud. There are different namesbeing used for platforms which caninclude the on-demand platform, orCloud 9. Its your choice on what youwould like to call the platform, but theyall have great potential in developing.When development teams createapplications for the cloud, they mustbuild its own cloud platform.InfrastructureSee also: Category:Cloud infrastructureCloud infrastructure services, alsoknown as "infrastructure as a service"(IaaS), deliver computer infrastructure –typically a platform virtualisationenvironment – as a service, along withraw (block) storage and networking.Rather than purchasing servers,software, data-center space or networkequipment, clients instead buy thoseresources as a fully outsourced service.Suppliers typically bill such services ona utility computing basis; the amount ofresources consumed (and therefore thecost) will typically reflect the level ofactivity.ServerThe servers layer consists of computerhardware and/or computer softwareproducts that are specifically designedfor the delivery of cloud services,including multi-core processors, cloud-specific operating systems and combinedofferingsCloud “Applications”SaaS resides hereMost common Cloud / Manyproviders of different servicesExamples: SalesForce, Gmail,Yahoo! Mail, Quicken OnlineAdvantages: Free, Easy,Consumer AdoptionDisadvantages: Limitedfunctionality, no control oraccess to underlying technology
Cloud “Platforms”“Containers”“Closed” environmentsExamples: Google App Engine,Heroku, Mosso, Engine Yard,Joyent or Force.com (SalesForceDev Platform)Advantages: Good fordevelopers, more control than“Application” Clouds, tightlyconfiguredDisadvantages: Restricted towhat is available, otherdependenciesCloud “InfrastructureProvide “Compute” and“Storage” cloudsVirtualization layers(hardware/software)Examples: Amazon EC2,GoGrid, Amazon S3, Nirvanix,LinodeAdvantages: Full control ofenvironments and infrastructureDisadvantages: premium pricepoint, limited competitionCloud “Extenders” (Wild Card)Provides extension to CloudInfrastructure and Platforms withbasic functionalityExamples: Amazon SimpleDB,Amazon SQS, Google BigTableAdvantages: Extendsfunctionality of Compute &Storage Clouds to integrate withlegacy system or other cloudsDisadvantages: Sometimesrequires use of specific Platformsor InfrastructureCloud “Aggregators” (Wild Card)Sits on top of various CloudInfrastructures for managementExamples: RightScale, AppistryAdvantages: Provides moreoptions for Cloud environmentsDisadvantages: Dependent onCloud ProvidersAdvantages of Cloud Computing
• Lower computer costs:– You do not need a high-powered and high-pricedcomputer to run cloudcomputings web-basedapplications.– Since applications run inthe cloud, not on thedesktop PC, your desktopPC does not need theprocessing power or harddisk space demanded bytraditional desktopsoftware.• Improved performance:– With few large programshogging your computersmemory, you will seebetter performance fromyour PC.– Computers in a cloudcomputing system bootand run faster becausethey have fewer programsand processes loaded intomemory…• Reduced software costs:– Instead of purchasingexpensive softwareapplications, you can getmost of what you needfor free-ish!– That is right - most cloudcomputing applicationstoday, such as the GoogleDocs suite, are totallyfree.That is a lot better thanpaying $200+ for similarMicrosoft Office software- which alone may bejustification for switchingto cloud applications• Instant software updates:– Another advantage tocloud computing is thatyou are no longer facedwith choosing betweenobsolete software andhigh upgrade costs.– When the application isweb-based, updateshappen automatically -available the next timeyou log into the cloud.– When you access a web-based application, you getthe latest version -without needing to payfor or download anupgrade.• Improved document formatcompatibility.– You do not have to worryabout the documents youcreate on your machinebeing compatible withother users applicationsor operating systems.– Where Word 2007documents cannot beopened on a computerrunning Word 2003, alldocuments can be read!There are potentially noformat incompatibilitieswhen everyone is sharingdocuments andapplications in the cloud• Unlimited storage capacity:– Cloud computing offersvirtually limitless storage.
– Your computers current200 Gbyte hard drive issmall compared to thehundreds of Pbytesavailable in the cloud.– Whatever you need tostore, you can.• Increased data reliability:– Unlike desktopcomputing, in which if ahard disk crashes anddestroy all your valuabledata, a computer crashingin the cloud should notaffect the storage of yourdata.– That also means that ifyour personal computercrashes, all your data isstill out there in the cloud,still accessible.– In a world where fewindividual desktop PCusers back up their dataon a regular basis, cloudcomputing is a data-safecomputing platform!• Universal document access:– That is not a problemwith cloud computing,because you do not takeyour documents with you.– Instead, they stay in thecloud, and you can accessthem whenever you havea computer and anInternet connection.– All your documents areinstantly available fromwherever you are.• Latest version availability:– Another document-related advantage ofcloud computing is thatwhen you edit adocument at home, thatedited version is what yousee when you access thedocument at work.The cloud always hoststhe latest version of yourdocuments; as long asyou are connected, youare not in danger ofhaving an outdatedversion• Easier group collaboration:– Sharing documents leadsdirectly to bettercollaboration.– Many users do this as it isan important advantagesof cloud computing -multiple users cancollaborate easily ondocuments and projects.– Because the documentsare hosted in the cloud,not on individualcomputers, all you need isan Internet connection,and you are collaborating.• Device independence.– You are no longertethered to a singlecomputer or network.– Changes to computers,applications anddocuments follow youthrough the cloud.– Move to a portabledevice, and yourapplications anddocuments are stillavailable.
Disadvantages of Cloud Computing• Requires a constant Internetconnection:– Cloud computing isimpossible if you cannotconnect to the Internet.– Since you use the Internetto connect to both yourapplications anddocuments, if you do nothave an Internetconnection you cannotaccess anything, evenyour own documents.– A dead Internetconnection means nowork and in areas whereInternet connections arefew or inherentlyunreliable, this could be adeal-breaker.When you are offline,cloud computing simply does not work• Can be slow:– Even with a fastconnection, web-basedapplications cansometimes be slower thanaccessing a similarsoftware program on yourdesktop PC.– Everything about theprogram, from theinterface to the currentdocument, has to be sentback and forth from yourcomputer to thecomputers in the cloud.– If the cloud servershappen to be backed up atthat moment, or if theInternet is having a slowday, you would not getthe instantaneous accessyou might expect fromdesktop applications.• Features might be limited:– This situation is bound tochange, but today manyweb-based applicationssimply are not as full-featured as their desktop-based applications.– For example, you can doa lot more with MicrosoftPowerPoint than withGoogle Presentationsweb-based offering.– The basics are similar,but the cloud applicationlacks many ofPowerPoints advancedfeatures.– If you are a power user,you might not want toleap into cloud computingjust yet.• HPC Systems:– Not clear that you can runcompute-intensive HPCapplications that useMPI/OpenMP!– Scheduling is importantwith this type ofapplication – as you wantall the VM to be co-
located to minimisecommunication latency!• General Concerns:– Each cloud systems usesdifferent protocols anddifferent APIs… so itmay not be possible torun applications betweencloud based systems.– Amazon has created itsown DB system (not SQL92), and workflow system(many popular workflowsystems out there) – soyour normal applicationswill have to be adapted toexecute on theseplatforms.The Future• Many of the activities looselygrouped together under cloudcomputing have already beenhappening and centralisedcomputing activity is not a newphenomena:• Grid Computing was the lastresearch-led centralisedapproach.• However there are concerns thatthe mainstream adoption of cloudcomputing could cause manyproblems for users.• Whether these worries aregrounded or not has yet to beseen.• Many new open source systemsappearing that you can install andrun on your local cluster – shouldbe able to run a variety ofapplications on these systems.CONCLUSION:Finally, cloud apps don’t eat up yourvaluable IT resources, so your CFO willlove it. This lets you focus on deployingmore apps, new projects, and innovation.Cloud computing is a simple idea, but itcan have a huge impact on your businessReferences1. ^ "Gartner Says Cloud ComputingWill Be As Influential As E-business". Gartner.com. Retrieved2010-08-22.2. ^ Gruman, Galen (2008-04-07)."What cloud computing reallymeans". InfoWorld. Retrieved 2009-06-02.3. ^ "Cloud Computing: Clash of theclouds". The Economist. 2009-10-15. Retrieved 2009-11-03.4. ^ Cloud Computing Defined 17 July2010. Retrieved 26 July 2010.5. ^ "Kerravala, Zeus, Yankee Group,"Migrating to the cloud isdependent on a convergedinfrastructure," Tech Target".Convergedinfrastructure.com.Retrieved 2011-12-02.6. ^ "Baburajan, Rajani, "The RisingCloud Storage Market OpportunityStrengthens Vendors," infoTECH,August 24, 2011". It.tmcnet.com.2011-08-24. Retrieved 2011-12-02.7. ^ "Oestreich, Ken, "ConvergedInfrastructure," CTO Forum,November 15, 2010".Thectoforum.com. 2010-11-15.Retrieved 2011-12-02.8. ^ Buyya, Rajkumar; Chee Shin Yeo,Srikumar Venugopal (PDF). Market-Oriented Cloud Computing: Vision,Hype, and Reality for Delivering ITServices as Computing Utilities.Department of Computer Science
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