文献翻译基于J2EE在分布式环境下的底层结构的自动动态配置应用.doc

文献翻译基于J2EE在分布式环境下的底层结构的自动动态配置应用.doc

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本科毕业设计

外文文献及译文

文献、资料题目：

InfrastructureforAutomaticDynamicDeploymentOfJ2EEApplication

inDistributedEnvironments

文献、资料来源：

网络

文献、资料发表（出版）日期：

2007.9

院（部）：

专业：

班级：

姓名：

学号：

指导教师：

翻译日期：

19

外文文献：

InfrastructureforAutomaticDynamicDeployment

OfJ2EEApplicationinDistributedEnvironments

AnatolyAkkerman,AlexanderTotok,andVijayKaramcheti

Abstract:

inordertoachievesuchdynamicadaptation,weneedaninfrastructureforautomatingJ2EEapplicationdeploymentinsuchanenvironment.ThisneedisquiteevidenttoanyonewhohasevertrieddeployingaJ2EEapplicationevenonasingleapplicationserver,whichisataskthatinvolvesagreatdealofconfigurationofboththesystemservicesandapplicationcomponents.

Keywords:

j2ee;component;Distributed;DynamicDeployment;

1Introduction

Inrecentyears,wehaveseenasignificantgrowthincomponent-basedenterpriseapplicationdevelopment.TheseapplicationsaretypicallydeployedoncompanyIntranetsorontheInternetandarecharacterizedbyhightransactionvolume,largenumbersofusersandwideareaaccess.Traditionallytheyaredeployedinacentrallocation,usingserverclusteringwithloadbalancing（horizontalpartitioning）tosustainuserload.However,horizontalpartitioninghasbeenshownveryefficientonlyinreducingapplication-relatedoverheadsofuser-perceivedresponsetimes,withouthavingmucheffectonnetwork-inducedlatencies.Verticalpartitioning（e.g.,runningwebtierandbusinesstierinseparateVMs）hasbeenusedforfaultisolationandloadbalancingbutitissometimesimpracticalduetosignificantrun-timeoverheads（evenifonewouldkeepthetiersonafastlocal-areanetwork）relatedtoheavyuseofremoteinvocations.Recentwork[14]inthecontextofJ2EEcomponentbasedapplicationshasshownviabilityofverticalpartitioninginwide-areanetworkswithoutincurringtheaforementionedoverheads.Thekeyconclusionsfromthatstudycanbesummarizedasfollows:

•Usingproperlydesignedapplications,verticaldistributionacrosswide-areanetworksimprovesuser-perceivedlatencies.

•Wide-areaverticallayeringrequiresreplicationofapplicationcomponentsandmaintainingconsistencybetweenreplicas.

•Additionalreplicasmaybedeployeddynamicallytohandlenewrequests.

•Differentreplicasmay,infact,bedifferentimplementationsofthesamecomponentbasedonusage（read-only,read-write）.

•Newrequestpathsmayreusecomponentsfrompreviouslydeployedpaths.

Applyingintelligentmonitoring[6]andAIplanning[2,12]techniquesinconjunctionwiththeconclusionsofthatstudy,weseeapotentialfordynamicadaptationinindustry-standardJ2EEcomponent-basedapplicationsinwideareanetworks

Throughdeploymentofadditionalapplicationcomponentsdynamicallybasedonactivemonitoring.However,inordertoachievesuchdynamicadaptation,weneedaninfrastructureforautomatingJ2EEapplicationdeploymentinsuchanenvironment.ThisneedisquiteevidenttoanyonewhohasevertrieddeployingaJ2EEapplicationevenonasingleapplicationserver,whichisataskthatinvolvesagreatdealofconfigurationofboththesystemservicesandapplicationcomponents.ForexampleonehastosetupJDBCdatasources,messagingdestinationsandotherresourceadaptersbeforeapplicationcomponentscanbeconfiguredanddeployed.Inawideareadeploymentthatspansmultipleservernodes,thisprovesevenmorecomplex,sincemoresystemservicesthatfacilitateinter-nodecommunicationsneedtobeconfiguredandstartedandavarietyofconfigurationdata,likeIPaddresses,portnumbers,JNDInamesandothershavetobeconsistentlymaintainedinvariousconfigurationfilesonmultiplenodes.

Thisdistributeddeploymentinfrastructuremustbeableto:

•addressinter-componentconnectivityspecificationanddefineitseffectsoncomponentconfigurationanddeployment,

•addressapplicationcomponentdependenciesonapplicationserverservices,theirconfigurationanddeployment,

•providesimplebutexpressiveabstractionstocontroladaptationthroughdynamicdeploymentandundeploymentofcomponents,

•enablereuseofservicesandcomponentstomaintainefficientuseofnetworknodes’resources,

•providethesefacilitieswithoutincurringsignificantadditionaldesigneffortonbehalfofapplicationprogrammers.

InthispaperweproposetheinfrastructureforautomaticdynamicdeploymentofJ2EEapplications,whichaddressesalloftheaforementionedissues.Theinfrastructuredefinesarchitecturedescriptionlanguages（ADL）forcomponentandlinkdescriptionandassembly.TheComponentDescriptionLanguageisusedtodescribeapplicationcomponentsandlinks.Itprovidesclearseparationofapplicationcomponentsfromsystemcomponents.Aflexibletypesystemisusedt