FIA-Serval原版完整课件_第1页
FIA-Serval原版完整课件_第2页
FIA-Serval原版完整课件_第3页
FIA-Serval原版完整课件_第4页
FIA-Serval原版完整课件_第5页
已阅读5页,还剩46页未读 继续免费阅读

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

Serval:AnEnd-HostStackforService-CentricNetworkingErikNordstrom,DavidShue,PremGopalan,RobertKieferMatveyArye,StevenY.Ko,JenniferRexford,MichaelJ.FreedmanNSDI2012PresentedbyYeTianforCourseCS05112OverviewRethinktheNetworkStackServalAbstractionTheServalNetworkStackExperimentsReviewModernInternetServiceMultiplicity(多重性)MultiplereplicasMultipleinterfacesMultiplepathsDynamism(动态性)ReplicafailureandrecoveryServicemigrationClientmobilityMatchespoorlywithtoday’sTCP/IPstackServiceAccessTodayDNSbindsservicetolocationatclient(earlybinding)DatacenterLBmapssingleIPtomultipleserversLBisapplication-specificMigrateVMstobalanceloadinthecloudFlowsbreakwhenswitchingnetworksorinterfacesRethinktheNetworkStackRethinktheNetworkStackApplication-layerToday’sapplicationsoperateontwolow-levelidentifiers(IPaddressandTCP/UDPport)Clientsmust“earlybind”totheseidentifiersusingout-of-bandlookupmechanisms(e.g.,DNS)oraprioriknowledge(e.g.,Webisonport80)beforeinitiatingcommunication.SocketprogrammingonIPaddressandportServal:applicationscommunicateoveractivesocketsusingserviceID,enableslatebindingofserviceIDtoaserviceinstances.RethinktheNetworkStackTransportlayerToday’sstackusesafive-tuple<remoteIP,remoteport,localIP,localport,protocol>todemultiplexanincomingpackettoasocket.Theinterfaceaddressescannotchangewithoutdisruptingongoingconnections–lackofmobilityServal:transportprotocolsdealonlywithdatadeliveryacrossoneormoreflows,includingretransmissionandcongestioncontrol;DemuxisattheSALlayerbasedonflowIDRethinktheNetworkStackNetworklayerToday’snetworklayeruseshierarchicalIPaddressingtoefficientlydeliverpackets.Challengedbytheneedforend-hostmobilityinastackwhereupper-layerprotocolsfailwhenaddresseschange.Serval:thenetworklayerunchanged.OverviewRethinktheNetworkStackServalAbstractionTheServalNetworkStackExperimentsReviewGroup-BasedServiceNamingAServalservicename,calledaserviceID,correspondstoagroupofoneormore(possiblychanging)processesofferingthesameservice.ServiceIDServicenamesdonotdictatethegranularityCanbeasingleSSHdaemon,aclusterofprinters,asetofpeersdistributingacommonfileFormatProviderprefixPrefix-basedaggregationandLPMExample:/cs/printerSecuringcommunicationandregistration:Endwithaself-certifyingbitstringExplicitHost-LocalFlowNamingServalprovidesexplicithost-localflownamingthroughflowIDsthatareassignedandexchangedduringconnectionsetup.Benefits:Network-layeroblivious:identifyflowswithoutknowingthenetwork-layeraddress.Mobilityandmultiplepaths:FlowIDshelpidentifyflowsacrossavarietyofdynamicevents,suchasmigration,addresschange,etc.OverviewRethinktheNetworkStackServalAbstractionTheServalNetworkStackExperimentsReviewTheServalNetworkStackSALisinclient,server

andservicerouterTheServalNetworkStackTheuser-spaceservicecontrollerManageserviceresolutionbasedonpoliciesListenforservice-relatedevents,monitorserviceperformance,andcommunicatewithothercontrollersTheServiceAccessLayer(SAL)providesaservice-leveldataplaneresponsibleforconnectingtoservicesthroughforwardingoverservicetables.Onceconnected,theSALmapsthenewflowtoitssocketintheflowtable,ensuringpacketdemultiplexed.ActiveSocketRetainthestandardBSDsocketinterface.AserviceIDisautomaticallyregisteredonacalltobind,andunregisteredonclose,processtermination,ortimeout.Onalocalserviceregistration,thestackupdatesthelocalservicetableandnotifiestheservicecontroller,whichmaynotifyupstreamservicecontrollers.Alocalunregistrationeventtriggerstheremovaloflocalrulesandnotificationoftheservicecontroller.ResolvingaserviceIDtonetworkaddressesisdelegatedtotheSALApplicationsjustcallthesocketinterfaceusingserviceIDsandneverseenetworkaddresses.AService-LevelDataPlaneThefirstpacketofanewconnection(synpacket)oranunconnecteddatagramincludesaserviceIDThestackperformslongestprefixmatching(LPM)ontheserviceIDtoselectarulefromtheservicetable.ActionsFORWARD:IncludeanassociatedsetofoneormoreIPaddressesEitherselectsalladdressesorusesweightedsamplingtoselectoneoftheaddresses.Foreachselecteddestination,thestackpassesapackettothenetworklayerfordelivery.DEMUX:Deliverareceivedpackettoalocalsocket,whenanserviceprocessislisteningontheserviceID.Addedbyanactivesocket’sbindeventActionsDELAY:QueuethepacketandnotifytheservicecontrolleroftheserviceID.allowaruletobeinstalled“on-demand”DROP:DiscardunwantedpacketExample:Connection-lessdatagramcommunicationServicerouter(SR)AclientapplicationinitiatescommunicationonserviceIDX,whichismatchedintheclient’sservicetabletoSR’saddress.Uponreceivingapacket,theSRlooksuptheserviceIDinitsownservicetable;givenaFORWARDrule,itforwardsthepackettotheserver.Attheserver,theDEMUXruledeliversthepackettothesocketofthelisteningapplication.Example:ConnectionestablishmentWhenclientaattemptstoconnecttoserviceX,theclient’sSALassignsalocalflowIDtothesocket,andthenaddsanentryinitsflowtable.ASYNpacketisgeneratedwiththeserviceIDfromtheconnectcall,alongwiththenewflowIDTheSALthenlooksuptherequestedserviceIDinitsservicetable,therequestissenttotheIPaddressbofthedefaultFORWARDruleForwardingcontinuesrecursivelythrougheUntilreachingalisteningserviceendpointsxonhostg,whichthencreatesarespondingsocketwithanewflowID,alsoupdatingitsflowtable.End-hostg’sSYN-ACKresponseincludesitsownaddress,flowIDTheSYN-ACKandallsubsequenttrafficinbothdirectionstraveldirectlybetweentheend-points,bypassingSRsb,cande.Afterthefirstpacket,allremainingpacketscanbedemultiplexedbytheflowtablebasedondestinationflowIDs.AnotherexampleClientaconnectstoserviceXAServiceControlPlaneforExtensibleServiceDiscoveryAserver’scontrollercan“announce”anewserviceinstancetoanupstreamservicecontrollerthat,inturn,disseminatesreachabilityinformationtoalargernetworkofcontrollers.serviceIDscanbeaggregatedbyadministrativeentitiesforscalabilityandresolutioncontrol.Ontheclient,theservicetablewouldhaveFORWARDrulestodirectaSYNpackettoitslocalservicerouter,whichinturndirectstherequestuptheservicerouterhierarchytoreachaserviceinstance.AcontrollerinstallsaDELAYrule,andmatchingpacketsarebufferedwhilethecontrollerresolvestheirserviceIDs.AreturnedmappingisinstalledasaFORWARDruleandthecontrollersignalsthestacktore-matchthedelayedpackets.Multi-homingandmulti-pathingServalcansplitasocket’sdatastreamacrossmultipleflowsestablishedandmaintainedbytheSALondifferentpaths.Onanypacket,eitherhostcanpiggybackalistofotheravailableinterfacesinaSALextensionheader,toenabletheotherhosttocreateadditionalflowsusingasimilarthree-wayhandshake.E.g.,ifS’sSYN-ACKpacketpiggybacksinformationaboutinterfaceaddressa4,Ccouldinitiateasecondflowfroma2toa4.TheSALcanfreelymigrateaflowfromoneaddress,interface,orpathtoanother.Example:Tomigratetheflow,CsendsSanRSYNpacket(for“resynchronize”)withflowIDs<fC1,fS1>andthenewaddressa2.TheserverreturnsanRSYN-ACK,whilewaitingforafinalacknowledgmenttoconfirmthechange.OverviewRethinktheNetworkStackServalAbstractionTheServalNetworkStackExperimentsReviewPerformancePrototypeof28,000linesofCcodeClient-serverthroughputcomparisonwithTCPComparingservicerouterwithIProuterTranslator:allowlegacyhosttocommunicateswithservalhostCaseExperiment:ReplicatedWebServicesFourclientsrunningtheApachebenchmarkgeneraterequeststoaServalwebservicewithanevolvingsetofMongooseserviceinstances.eachclientrequestsa3MBfileandmaintainsanopenwindowof20HTTPrequestsAttime60,twonewserviceinstancesstart,registerwiththeservicerouterAttime120,weforcethefirsttwoserverstogracefullyshutdown,whichcausesthemtoclosetheirlisteningsocketStartanotherserverattime180,CaseExperiment:Back-EndDistributedStorageImplementedadynamicMemcachedsystem.Memcachedprovidesasimplekey-valueGET/SETcachingservice,where“keyspace”partitionsarespreadoveranumberofserversforloadbalancingClientsissuerequestsdirectlytoaserviceID.TheSALthenmapstheserviceIDtoapartitionusingLPMintheservicetable,andultimatelyforwardstherequesttoaresponsibleserverthatlistensonthecommon

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论