CloudResearch云服务09.docx

CloudResearch云服务09.docx

《CloudResearch云服务09.docx》由会员分享，可在线阅读，更多相关《CloudResearch云服务09.docx（19页珍藏版）》请在冰豆网上搜索。

CloudResearch云服务09

TheRESERVOIRModelandArchitectureforOpenFederatedCloudComputing

B.Rochwerger

D.Breitgand

E.Levy

A.Galis

K.Nagin

I.Llorente

R.Montero

Y.Wolfsthal

E.Elmroth

J.Caceres

M.Ben-Yehuda

W.Emmerich

F.Galan´

Abstract

Theemergingcloudcomputingparadigmisrapidlygainingmomentumasanalterna-tivetotraditionalIT.However,contemporarycloudcomputingofferingsaremostlygearedtowardsWeb2.0styleapplicationsandonlyrecentlyhavebeguntoaddresstheneedsofenterprise-gradesolutions,suchassupportforinfrastructure-levelSLAs.

Toaddressthechallengesanddeficienciesinthecurrentstateoftheart,weproposeamodular,extensiblecloudarchitecturewithintrinsicsupportforBusinessServiceMan-agement（BSM）andfederationofclouds.Ourgoalistofacilitateanopen,service-based,on-lineeconomy,whereresourcesandservicesaretransparentlyprovisionedandmanagedacrosscloudsonanon-demandbasisatcompetitivecostswithhighqualityofservice.

WepresentthevisiondrivingtheRESERVOIRproject-anarchitecturethatallowsprovidersofcloudinfrastructuretodynamicallypartnerwitheachothertocreateaseem-inglyinfinitepoolofITresourceswhilefullypreservingtheautonomyoftechnologicalandbusinessmanagementdecisions.Tothisend,RESERVOIRleveragesandextendsthead-vantagesofvirtualizationandembedsautonomousmanagementintotheinfrastructure.Atthesametime,theRESERVOIRapproachaimstoachieveaveryambitiousgoal-creatingafoundationfornext-generationenterprise-gradecloudcomputing.

1Introduction

IntheWeb2.0era,companiesgrowfrominceptiontoamassivescaleatincrediblerates.Forexample,MySpaceacquired20millionusersintwoyears;YouTubereachedthesamenumberofusersinjust16months[1].However,toleveragethispotentialrateofgrowth,companiesmustproperlyaddresscriticalbusinessdecisionsrelatedtotheirservicedeliveryinfrastructure.

TheemergingCloudComputingparadigm[2],asexemplifiedbytheAmazonElasticCom-puteCloud（EC2）,representsapromisingconceptualfoundationforhostinganddeploymentofweb-basedserviceswhiletheoreticallyrelievingserviceprovidersfromtheresponsibilityofprovisioningthecomputationalresourcesneededtosupporttheseservices.Cloudcomputingoffersmultipleadvantages:

itallowsindividualsorcompanieswithmarketdomainexpertisetobuildandruntheirSoftwareasaService（SaaS）companywithminimaleffortinsoftwaredevel-opmentandwithoutmanaginganyhardwareoperations.Thishelpsreducesoftwarecomplexityandcosts,expeditetime-to-market,andenhanceaccessibilityofconsumers.

Withcloudcomputing,companiescanleaseinfrastructureresourceson-demandfromavir-tuallyunlimitedpool.The“payasyougo”billingmodelapplieschargesfortheactuallyused

TheresearchleadingtotheseresultsispartiallysupportedbytheEuropeanCommunity’sSeventhFrameworkProgramme（FP7/2001-2013）undergrantagreementn215605.

1

resourcesperunittime.Thisway,abusinesscanoptimizeitsITinvestmentandimproveavail-abilityandscalability.

Whilecloudcomputingholdshugepromiseforthefutureofservicecomputing,anumberofinherentdeficienciesincurrentofferingscanbepointedout:

Inherentlylimitedscalabilityofsingle-providerclouds:

Althoughmostinfrastructurecloudproviderstodayclaiminfinitescalability,inrealityitisreasonabletoassumethateventhelargestplayersmaystartfacingscalabilityproblemsasCloudComputingusagerateincreases.Inthelongterm,scalabilityproblemsmaybeexpectedtoaggravateascloudprovidersserveanincreasingnumberofon-lineservices,eachaccessedbymassiveamountsofglobalusersatalltimes.

Lackofinteroperabilityamongcloudproviders:

Contemporarycloudtechnologieshavenotbeendesignedwithinteroperabilityinmind.Thisresultsinaninabilitytoscalethroughbusinesspartnershipsacrosscloudsproviders.Inaddition,itpreventssmallandmediumcloudinfrastructureprovidersfromenteringthecloudprovisioningmarket.Overall,thisstiflescompetitionandlocksconsumerstoasinglevendor.

Nobuilt-inBusinessServiceManagementsupport:

BusinessServiceManagement（BSM）isamanagementstrategythatallowsbusinessestoaligntheirITmanagementwiththeirhighlevelbusinessgoals.ThekeyaspectofBSMisServiceLevelAgreement（SLA）manage-ment.CurrentcloudcomputingsolutionsarenotdesignedtosupporttheBSMpracticesthatarewellestablishedinthedailymanagementoftheenterpriseITdepartments.Asaresult,enterpriseslookingattransformingtheirIToperationstocloud-basedtechnologiesfaceanon-incrementalandpotentiallydisruptivestep.

Wearguethatnoneoftheseproblems,aswellasothermajorproblemssuchassecurityandavailability,arenotremediablebyretrofittingexistingarchitectures.Onthecontrary,theseissuesshouldbeaddressedbyproperdesignofacloudcomputingarchitecturefrombasicprinciples.Inthispaper,weproposeareferencemodelandarchitecturethatsystematicallyaddresssomeofthosedeficienciesandserveasapotentialfoundationfordeliveringITservicesasutilitiesovertheInternet.

1.1TheRESERVOIRApproach

TheRESERVOIRvisionistoenableon-demanddeliveryofITservicesatcompetitivecosts,withoutrequiringalargecapitalinvestmentininfrastructure.OurmodelisinspiredbyastrongdesiretolikenthedeliveryofITservicestothedeliveryofcommonutilities.Forexample,acommonscenariointheelectricgridisforonefacilitytodynamicallyacquireelectricityfromaneighboringfacilitytomeetaspikeindemand.Wedeemthatsimilarlytootherindustries,wherenosingleproviderservesallcustomersatalltimes,next-generationcloudcomputinginfrastruc-tureshouldsupportamodelwheremultipleindependentproviderscancooperateseamlesslytomaximizetheirbenefit.

Morespecifically,webelievethattotrulyfulfillthepromiseofcloudcomputing,thereshouldbetechnologicalcapabilitiestofederatedisparatedatacenters,includingthoseownedbyseparateorganizations.Onlythroughfederationandinteroperabilitycaninfrastructureproviderstakeadvantageoftheiraggregatedcapabilitiestoprovideaseeminglyinfiniteservicecomputingutility.Informally,werefertotheinfrastructurethatsupportsthisparadigmasafederatedcloud.

Anadditionalimportantadvantageofferedbythefederatedcloudapproachisthatitdemoc-ratizesthesupplysideofcloudcomputingandallowssmallandmedium-sizedbusinessesandnewentrantstobecomecloudproviders.Thisencouragescompetitionandinnovation.

2

Asdiscussedabove,oneofthelimitingfactorsincurrentcloudcomputingofferingsisthelackofsupportforBSM,specificallyforbusiness-alignedSLAmanagement.WhilespecificcloudcomputingsolutionscanbeenhancedwithsomeaspectsofBSM,theprovisioningofcomplexservicesacrossafederatednetworkofpossiblydisparatedatacentersisadifficultandyetunsolvedproblem.Aservicemaybeacompositionofnumerousdistributedresources,includingcomputing,storage,andnetworkelements.Provisioningsuchaserviceconsumesphysicalresources,butshouldnotcauseanSLAviolationofanyotherrunningapplicationwithaprobabilitylargerthansomepredefinedthreshold.AsSLAsserveasriskmitigationmechanisms,thisthresholdrepresentstheriskthatacloudproviderandthecloudcustomerarewillingtoaccept.

WithBSM,applicationsareproperlydimensioned,andtheirnon-functionalcharacteristics（e.g.,performance,availability,security,etc.）,governedbySLAs,areensuredwithoptimalcostthroughcontinuousIToptimization.Wearguethatduetotheimmensescaleenvisionedbycloudcomputing,supportforBSMshouldbemaximallyautomatedandembeddedintothecloudinfrastructure.

IntheRESERVOIRmodel,eachinfrastructureproviderisanautonomousbusinesswithitsownbusinessgoals.Aproviderfederateswithotherproviders（i.e.,otherRESERVOIRsites）basedonitsownlocalpreferences.TheITmanagementataspecificRESERVOIRsiteisfullyautonomousandgovernedbypoliciesthatarealignedwiththesite’sbusinessgoals.Toopti-mizethisalignment,onceinitiallyprovisioned,resourcescomposingaservicemaybemovedtootherRESERVOIRsitesbasedoneconomical,performance,oravailabilityconsiderations.Ourresearchaddressesthoseissuesandseekstominimizethebarrierstodeliveringservicesasutilitieswithguaranteedlevelsofserviceandproperriskmitigation.

Cloudcomputingisthelatestincarnationofageneral-purposepubliccomputingutility.Inrecentyearswehaveseenthemanyeffortstowardscomputingasautility-fromgridcomput-ing[3],whichmadesignificantprogressintheareaofhighperformancescientificcomputing,toattemptsatbuildingenterprise-levelutilities[4].However,noneoftheseattemptshavemateri-alizedintoageneralpurposecomputeutilityaccessiblebyanyone,atanytime,fromanywhere.

Whatmakescloudcomputingdifferentisthatindustrytrendssuchasubiquityofbroad-bandnetworks,fastpenetrationofvirtualizationtechnologyforx86-basedservers[5],andtheadoptionofSoftwareasaService[6]arefinallycreatinganopportunityandaneedforaglobalcomputingutility.Thereluctancetouseon-lineservicesasareplacementfortraditionalsoftwareislessening–thesuccessofcompaniessuchasprovesthatwiththerightsetofsecuritywarrantiesandacompetitiveprice,companiesarewillingtotrusteventheirmostvalu-abledata–customerrelations–toanon-lineserviceprovider.Atthesametime,virtualizationhasmadeitpossibletode