VMware Infrastructure Architecture Overview

W H I T E P A P E R

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Table of Contents

Physical Topology of the VMware Infrastructure Data Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Virtual Data Center Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Hosts, Clusters and Resource Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

VMware VMotion, VMware DRS and VMware HA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Networking Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Storage Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

VMware Consolidated Backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

ESX Server External Interfacing Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

VirtualCenter Management Server Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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VMware Infrastructure architecture Overview

• VirtualInfrastructureWebAccess–AWebinterfaceforvirtualmachinemanagementandremoteconsolesaccess

• VMwareVMotion™–Enablesthelivemigrationofrunningvirtualmachinesfromonephysicalservertoanotherwithzerodowntime,continuousserviceavailabilityandcompletetransactionintegrity

• VMwareHighAvailability(HA)–Provideseasy-to-use,cost-effectivehighavailabilityforapplicationsrunninginvirtualmachines.Intheeventofserverfailure,affectedvirtualmachinesareautomaticallyrestartedonotherproductionserversthathavesparecapacity

• VMwareDistributedResourceScheduler(DRS)–Intelligentlyallocatesandbalancescomputingcapacitydynamicallyacrosscollectionsofhardwareresourcesforvirtualmachines

• VMwareConsolidatedBackup–Providesaneasytouse,centralizedfacilityforagent-freebackupofvirtualmachines.ItsimplifiesbackupadministrationandreducestheloadonESXServerinstallations

• VMwareInfrastructureSDK–ProvidesastandardinterfaceforVMwareandthird-partysolutionstoaccessVMwareInfrastructure

VMwareInfrastructureincludesthefollowingcomponentsasshowninFigure1-1:

• VMwareESXServer–Aproduction-provenvirtualizationlayerrunonphysicalserversthatabstractprocessor,memory,storageandnetworkingresourcestobeprovisionedtomultiplevirtualmachines

• VMwareVirtualMachineFileSystem(VMFS)–Ahigh-perfor-manceclusterfilesystemforvirtualmachines

• VMwareVirtualSymmetricMulti-Processing(SMP)–Enablesasinglevirtualmachinetousemultiplephysicalprocessorssimultaneously

• VirtualCenterManagementServer–Thecentralpointforconfiguring,provisioningandmanagingvirtualizedITinfra-structure

• VirtualInfrastructureClient(VIClient)–AninterfacethatallowsadministratorsanduserstoconnectremotelytotheVirtualCenterManagementServerorindividualESXServerinstallationsfromanyWindowsPC

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what is Virtualization and what are Virtual Machines?VirtualizationisanabstractionlayerthatdecouplesthephysicalhardwarefromtheoperatingsystemtodelivergreaterITresourceutilizationandflexibility.Virtualizationallowsmultiplevirtualmachines,withheterogeneousoperatingsystems(e.g.,Windows�00�ServerandLinux)andapplicationstoruniniso-lation,side-by-sideonthesamephysicalmachine.

Avirtualmachineistherepresentationofaphysicalmachinebysoftware.Ithasitsownsetofvirtualhardware(e.g.,RAM,CPU,NIC,harddisks,etc.)uponwhichanoperatingsystemandapplicationsareloaded.Theoperatingsystemseesaconsistent,normalizedsetofhardwareregardlessoftheactualphysicalhardwarecomponents.VMwarevirtualmachinescontainadvancedhardwarefeaturessuchas64-bitcomputingandvirtualsymmetricmultipro-cessing.

Formoreinformationonvirtualization,pleasereadtheVirtualizationOverviewVMwarewhitepaper.

VMware® Infrastructure is the industry’s first full infrastruc-ture virtualization suitethatallowsenterprisesandsmallbusi-nessesaliketotransform,manageandoptimizetheirITsystemsinfrastructurethroughvirtualization.VMwareInfrastructuredeliverscomprehensivevirtualization,management,resourceoptimization,applicationavailabilityandoperationalautoma-tioncapabilitiesinanintegratedoffering.

Figure 1-1: VMware Infrastructure

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ThefollowingsectionsdescribethearchitectureofVMwareInfrastructure,beginningwiththeelementsthatmakeupitsphysicaltopology,followedbythevirtual,orlogical,viewofVMwareInfrastructurewheretherelationshipsbetweenthevirtualarchitecturalelementsandthephysicalworldareexplored.Lastly,thearchitecturesoftwocoreVMwareInfrastructurecomponentsarediscussedinfurtherdetail.

Physical Topology of the VMware Infrastructure Data CenterWith VMware Infrastructure, IT departments can build a virtual data center using their existing industry standard technology and hardware . Thereisnoneedtopurchasespecializedhardware.Inaddition,VMwareInfrastructureallowsuserstocreateavirtualdatacenterthatiscentrallymanagedbymanagementserversandcanbecontrolledthroughawideselectionofinterfaces.Figure 1-2: VMware Infrastructure Data Center Physical Building Blocks

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Figure 1-3: VirtualCenter Management Server centrally manages the assign-ment of virtual machines to physical servers

Storage Networks and ArraysFiberChannelSANarrays,iSCSISANarraysandNASarraysarewidely-usedstoragetechnologiessupportedbyVMwareInfrastructuretomeetdifferentdatacenterstorageneeds.Sharingthestoragearraysbetween(byconnectingthemto)groupsofserversviastorageareanetworksallowsaggregationofthestorageresourcesandprovidesmoreflexibilityinprovi-sioningthemtovirtualmachines.

IP NetworksEachcomputingservercanhavemultiplegigabitEthernetnetworkinterfacecards(NICs)toprovidehighbandwidthandreliablenetworkingtotheentiredatacenter.

Management ServerTheVirtualCenterManagementServerprovidesaconvenientsinglepointofcontroltothedatacenter.ItrunsonWindows�00�Servertoprovidemanyessentialdatacenterservicessuchasaccesscontrol,performancemonitoringandconfiguration.Itunifiestheresourcesfromtheindividualcomputingserverstobesharedamongvirtualmachinesintheentiredatacenter.AsshowninFigure1-�,VirtualCenterManagementServeraccom-plishesthisbymanagingtheassignmentofvirtualmachinestothecomputingservers.VirtualCenterManagementServeralsomanagestheassignmentofresourcestothevirtualmachineswithinagivencomputingserverbasedonthepoliciessetbythesystem administrator.

AsFigure1-�shows,atypicalVMwareInfrastructuredatacenterconsistsofbasicphysicalbuildingblockssuchasx86comput-ingservers,storagenetworksandarrays,IPnetworks,amanage-mentserveranddesktopclients.

Computing ServersThecomputingserversareindustrystandardx86serversthatrunVMwareESXServeronthe“baremetal.”EachcomputingserverisreferredtoasastandaloneHostinthevirtualenviron-ment.Anumberofsimilarlyconfiguredx86serverscanbegroupedtogetherwithconnectionstothesamenetworkandstoragesubsystemstoprovideanaggregatesetofresourcesinthevirtualenvironment,calledaCluster.

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ComputingserverswillcontinuetofunctionevenintheunlikelyeventthatVirtualCenterManagementServerbecameunreachable(e.g.,thenetworkissevered).Computingserverscanbemanagedseparatelyandwillcontinuetoruntheirassignedvirtualmachinesbasedontheresourceassignmentsthatwerelastset.OncetheVirtualCenterManagementServerbecomesavailable,itcanmanagethedatacenterasawholeagain.

ThearchitectureofVirtualCenterManagementServerwillbedescribedindetailinlatersections.

Desktop ClientsVMwareInfrastructureprovidesaselectionofinterfacesfordatacentermanagementandvirtualmachineaccess.Userscanchoosetheinterfacethatbestmeetstheirneeds:VirtualInfrastructureClient(VIClient),WebAccessthroughaWebbrowser,orterminalservices(suchasWindowsTerminalServicesorXterm).

Virtual Data Center architectureVMwareInfrastructurevirtualizestheentireITinfrastructureincludingservers,storageandnetworks.Itaggregatestheseheterogeneousresourcesandpresentsasimpleanduniformsetofelementsinthevirtualenvironment. With VMware Infrastructure, IT resources can be managed like a shared utility and dynamically provisioned to different business units and projects without worrying about the underlying hardware differences and limitations .

Figure 1-4: Virtual Data Center Architecture

AsshowninFigure1-4,VMwareInfrastructurepresentsasimplesetofvirtualelementsusedtobuildavirtualdatacenter:

• ComputingandmemoryresourcescalledHosts,ClustersandResourcePools

• StorageresourcescalledDatastores

• NetworkingresourcescalledNetworks

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AHostisthevirtualrepresentationofthecomputingandmemoryresourcesofaphysicalmachinerunningESXServer.Whenoneormorephysicalmachinesaregroupedtogethertoworkandbemanagedasawhole,theaggregatecomput-ingandmemoryresourcesformaCluster.MachinescanbedynamicallyaddedorremovedfromaCluster.ComputingandmemoryresourcesfromHostsandClusterscanbefinelyparti-tionedintoahierarchyofResourcePools.

Datastoresarevirtualrepresentationsofcombinationsofunderlyingphysicalstorageresourcesinthedatacenter.ThesephysicalstorageresourcescancomefromthelocalSCSIdisksoftheserver,theFiberChannelSANdiskarrays,theiSCSISANdiskarrays,orNetworkAttachedStorage(NAS)arrays.

Networksinthevirtualenvironmentconnectvirtualmachinestoeachotherortothephysicalnetworkoutsideofthevirtualdatacenter.

VirtualmachinesaredesignatedtoaparticularHost,ClusterorResourcePoolandaDatastorewhentheyarecreated.Avirtualmachineconsumesresourceslikeaphysicalapplianceconsumeselectricity.Whileinpowered-off,suspended,oridlestate,itconsumesnoresources.Oncepowered-on,itconsumesresourcesdynamically,usingmoreastheworkloadincreasesorgivebackresourcesdynamicallyastheworkloaddecreases.

Provisioning of virtual machines is much faster and easier than physical machines .Newvirtualmachinescanbecreatedinseconds,nopurchaseorderisrequired,nowaiting,nophysicalconstraintstoworryabout.Onceavirtualmachineisprovisioned,theappropriateoperatingsystemandapplicationscanbeinstalledunalteredonthevirtualmachinetohandleaparticularworkloadjustasthoughtheywerebeinginstalledonaphysicalmachine.Tomakethingseasier,avirtualmachinecanevenbeprovisionedwiththeoperatingsystemandappli-cationsalreadyinstalledandconfigured.

Resources are provisioned to virtual machines based on the policies set by the system administrator who owns the resources .Thepoliciescanreserveasetofresourcesforaparticularvirtualmachinetoguaranteeitsperformance.Thepoliciescanalsoprioritizeandsetavariableportionofthetotalresourcestoeachvirtualmachine.Avirtualmachinewillbepreventedfrombeingpowered-on(toconsumeresources)ifdoingsowouldviolatetheresourceallocationpolicies.Formoreinformationonresourcemanagement,pleaseseetheResourceManagementGuide.

Thefollowingsectionsexamineindetailthevirtualelementsofthedatacenter.

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Hosts, Clusters and resource PoolsHosts, Clusters and Resources Pools provide flexible and dynamic ways to organize the aggregated computing and memory resourcesinthevirtualenvironmentandlinkthembacktotheunderlyingphysicalresources.

AHostrepresentstheaggregatecomputingandmemoryresourcesofaphysicalx86server.Forexample,ifthephysicalx86serverhasfourdual-coreCPUsrunningat4GHzeachand��GBofsystemmemory,thentheHostwillhave��GHzofcomputingpowerand��GBsofmemoryavailableforrunningvirtualmachinesthatareassignedtoit.

AClusterrepresentstheaggregatecomputingandmemoryresourcesofagroupofphysicalx86serverssharingthesamenetworkandstoragearrays.Forexample,ifthegroupcontains8servers,eachserverhas4dual-coreCPUsrunningat4GHzeachand��GBofmemory.TheClusterwillthenhave��6GHzofcomputingpowerand��6GBofmemoryavailablefortherunningvirtualmachinesassignedtoit.

Thevirtualresourceownersdonotneedtobeconcernedwiththephysicalcomposition(numberservers,quantityandtypeofCPUs—Multi-core,Hyperthreading,etc)oftheunderlyingClustertoprovisionresources.Theysimplysetuptheresourceprovisioningpoliciesbasedontheaggregateavailableresource.VMwareInfrastructurewillautomaticallyassigntheappropri-ateresourcesdynamicallytothevirtualmachineswithintheboundariesofthosepolicies.

Figure 1-5: Hosts, Clusters and Resource Pools

ResourcesPoolsprovideaflexibleanddynamicwaytodivideandorganizecomputingandmemoryresourcesfromaHostoraCluster.AnyResourcePoolscanbepartitionedintosmallerResourcePoolsatafine-grainleveltofurtherdivideandassignresourcestodifferentgroupsorfordifferentpurposes.

Figure1-�illustratestheconceptofResourcePools.Threex86serverswith4GHzcomputingpowerand16GBofmemoryeachareaggregatedtoformaClusterof1�GHzcomputingpowerand48GHzofmemory.AResourcePool(“FinanceDepartment”)reserves8GHzcomputingpowerand��GBsoffromtheCluster,leaving4GHzcomputingpowerand16GBsofmemoryforthevirtualmachine“Others.”Fromthe“FinanceDepartment”ResourcePool,asmallerResourcePool(“Accounting”)reserves4GHzcomputingpowerand16GBsforthevirtualmachinesfromtheaccountingdepartment.Thatleaves4GHzand16GBsofmemoryforthevirtualmachinecalled“Payroll”.Resources reserved can be dynamically changed . Imaginethatatyearend,Accounting’sworkloadincreases,theuserwantstoincreasetheResourcePool“Accounting”fromreserving4GHzofcomputingpowerto6GHz.Wecansimplymake the change to the Resource Pool dynamically without shutting down the associated virtual machines .ResourcesreservedforaResourcePoolorvirtualmachinearenottakenawayimmediately.Theydynamicallyrespondtothedemand.Forexample,ifthe4GHzofcomput-ingresourcesreservedfortheAccountingdepartmentarenotbeingused,virtualmachine“Payroll”canmakeuseoftheremainingprocessingcapacityduringitspeaktime.WhenAccountingagainrequirestheprocessingcapacity,“Payroll”willdynamicallygivethemback.Asaresult,even though resources are reserved for different Resource Pools, they are not being wasted if not used by their owner .

Asdemonstratedbytheexample,ResourcePoolscanbenested,organizedhierarchicallyanddynamicallyreconfiguredsothattheITenvironmentmatchesthecompanyorganiza-tion.Individualbusinessunitscanusededicatedinfrastructureresourceswhilestillbenefitingfromtheefficiencyofresourcepooling.

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VMware VMotion, VMware DrS and VMware HaVMwareVMotion,VMwareDRSandVMwareHAaredistributedservicesthatenableefficientandautomatedresourcemanage-mentandhighvirtualmachineavailability.

VMware VMotionAsmentionedearlier,virtualmachinesrunonandconsumeresourcesfromindividualphysicalx86serversthroughVMwareESXServer.VMotionenablesthemigrationofrunningvirtualmachinesfromonephysicalservertoanotherwithoutserviceinterruptionasshowninFigure1-6.Thisallowsvirtualmachinestomovefromaheavilyloadedservertoalightlyloadedone.Theeffectisamoreefficientassignmentofresources.Hence,withVMotion,resourcescanbedynamicallyreallocatedtovirtualmachinesacrossphysicalservers.

Figure 1-6: VMware VMotion

Figure 1-7: VMware DRS

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VMware DRSTakingtheVMotioncapabilityonestepfurtherbyaddinganintelligentscheduler, VMware DRS enables the system administrator to set resource assignment policies that reflect business needs and let VMware DRS do the cal-culation and automatically handle the detailed physical resource assignments .VMwareDRSdynamicallymonitorstheworkloadoftherunningvirtualmachinesandtheresourceutilizationofthephysicalserverswithinaCluster.Itchecksthoseresultsagainsttheresourceassignmentpolicies,ifthereisapotentialforviolationorimprovement,itutilizesVMotionanddynamicallyreassignsvirtualmachinestodifferentphysicalservers,asshowninFigure1-�,toensurethatthepoliciesarecompliedandresourceallocationisoptimal.

Ifanewphysicalserverismadeavailable,VMwareDRSauto-maticallyredistributesthevirtualmachinestotakeadvantageofit.Conversely,ifaphysicalserverneedstobetakendownforanyreason,VMwareDRSredistributesitsvirtualmachinestootherserversautomatically.Formoreinformation,seetheVMwareDRSwhitepaper.

VMware HAVMware HA offers a simple and low cost high availability alternative to application clustering .ItenablesquickrestartofvirtualmachinesonadifferentphysicalserverwithinaClusterautomaticallyshouldthehostingserverfail.Allapplica-tionswithinthevirtualmachineswillbenefitfromhighavail-ability,notjustoneaswithapplicationclustering.

VMwareHAworksbyplacinganagentoneachphysicalservertomaintaina“heartbeat”withtheotherserversintheCluster.AsshowninFigure1-8,lossofa“heartbeat”fromoneserverautomaticallyinitiatestherestartingofallaffectedvirtualmachinesonotherservers.

SettingupVMwareHAcanbedonesimplybydesignatingthepriorityorderofvirtualmachinestoberestartedintheCluster.Thisisverysimplewhencomparedtothesetupandconfigura-tioneffortrequiredforapplicationclustering.Furthermore,eventhoughVMwareHArequiresacertainamountofnon-reservedresourcestobemaintainedatalltimestoensurethattheremainingliveserverscanhandlethetotalworkload,itdoesnotrequiredoublingtheamountofresourceslikeapplicationclustering.Formoreinformation,seetheVMwareHAwhitepaper.

Figure 1-8 . VMware HA

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Networking architectureVMware Infrastructure is the only solution that provides a rich set of virtual networking elementsthatmakesnet-workingthevirtualmachinesinthedatacenteraseasyandsimpleasinthephysicalenvironment.Furthermore,itenablesanewsetofcapabilitiesnotpossibleinthephysicalenviron-mentbecausemanyofthelimitationsinthephysicalworlddon’tapply.

Figure 1-9: Networking Architecture

or provide failover in the event of an adapter hardware failure .ThefailoveristransparenttoallvirtualmachineswithouttheneedtoconfigureanyofthemspecificallyforNICteaming.ForinformationonNICteaming,seetheServerConfigurationGuide.

Port Group is a unique concept in the virtual environ-ment . A Port Group is a mechanism for setting policies that govern the network connected to it . AvSwitchcanhavemultiplePortGroups.InsteadofconnectingtoaparticularportonthevSwitch,avirtualmachineconnectsitsvNICtoaPortGroup.AllvirtualmachinesthatconnecttothesamePortGroupbelongtothesamenetworkinsidethevirtualenviron-menteveniftheyareondifferentphysicalserversasshowninFigure1-9.NetworkCisthesameonbothHost1andHost�.

Evenifallotherconditionsaremet,avirtualmachinecanVMotionfromonephysicalservertoanotheronlyifbothservershavethesamevSwitch(withthesamePortGroups).ThenetworkconnectionismaintainedafterfollowingtheVMotionMigrationbecausethevirtualmachineisautomaticallyconnectedtothesamePortGrouponthesamevSwitchonnewhostingserver.

PortGroupscanbeconfiguredtoenforceanumberofpoliciesthatprovideenhancednetworkingsecurity,networksegmenta-tion,betterperformance,higheravailabilityandtrafficmanage-ment:

• Layer�securityoptionscanbesetforaPortGrouptoisolate compromised or malicious virtual machinesandpreventthemfrompotentiallydoingharmtoothermachinesinthenetwork.

• VLANsupportcanbeconfiguredforaPortGrouptoallowsegmentationofthenetwork

• SpecificNICteamingpoliciescanbesetforanindividualPortGroup(Network)tosharetrafficloadorprovidefailoverincaseofhardwarefailure

• TrafficShapingpoliciescanbesettoimprovetrafficmanage-ment

FormoreinformationonPortGroupconfiguration,pleaseseetheServerConfigurationGuide.

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Figure1-9showstherelationshipbetweenthenetworksinsideandoutsidethevirtualenvironment.Thevirtualenvironmentprovidessimilarnetworkingelementsasthephysicalworld.Theyarevirtualnetworkinterfacecards(vNIC),virtualswitchs(vSwitch)andPortGroups.

Likeaphysicalmachine,eachvirtualmachinehasitsownvNICs.TheoperatingsystemandapplicationstalktothevNICsthroughastandardnetworkingdevicedriveroraVMwareoptimizednetworkingdevicedriverjustasthoughthevNICisaphysicalNIC.Totheoutsideworldalso,eachvNICappearsjustlikeaphysicalNIC–ithasitsownMACaddress,oneormoreIPaddressesanditrespondstothestandardEthernetprotocolexactlyasaphysicalNICwould.

AvSwitchworkslikeaLayer�physicalswitch.EachphysicalserverhasitsownvSwitches.OnonesideofthevSwitcharePortGroupswhichconnecttovirtualmachines.OntheothersideareuplinkconnectionstophysicalEthernetadaptersontheserverwherethevSwitchresides.VirtualmachinesconnecttotheoutsideworldthroughthephysicalEthernetadaptersthatareconnectedtothevSwitchuplinks.

AvirtualswitchcanconnectitsuplinkstomorethanonephysicalEthernetadaptertoenableNIC teaming two or more physical adapters used to share the traffic load

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Storage architectureThe VMware Infrastructure enables enterprise-class storage performance, functionality and availability without adding complexity totheuserapplicationsandguestoperatingsystems.

TheVMwareInfrastructureStorageArchitectureconsistsoflayersofabstractionthathideandmanagethecomplexityanddifferencesbetweenphysicalstoragesubsystemsandpresentsimplestandardstorageelementstothevirtualenvironment(seeFigure1-10).Totheapplicationsandguestoperatingsystemsinsideeachvirtualmachine,storageispresentedsimplyasSCSIdisksconnectedtoavirtualBusLogicorLSISCSIHostBusAdapter.

Figure 1-10: Storage Architecture

ADatastoreisphysicallyaVMFSfilesystemvolumeoradirec-toryonaNASdevice.EachDatastorecanspanmultiplephysicalstoragesubsystems.AsshowninFigure1-10,asingleVMFSvolumecancontainoneormoreLUNsfromadirectattachedSCSIdiskarrayonaphysicalserver,aFiberChannelSANdiskfarm,oriSCSISANdiskfarm.NewLUNsaddedtoanyofthephysicalstoragesubsystemsareautomaticallydiscoveredandmadeavailable.TheycanbeaddedtoextendapreviouslycreatedDatastorewithoutpoweringdownphysicalserversorstoragesubsystems.Conversely,ifanyoftheLUNswithinaDatastorefailsorbecomesunavailable,onlythosevirtualmachinesthatresideinthatLUNareaffected.AllothervirtualmachinesresidinginotherLUNscontinuetofunctionasnormal.

VMFSisaclusteredfilesystemthatleveragessharedstoragetoallowmultiplephysicalserverstoreadandwritetothesamestoragesimultaneously.VMFSprovideson-diskdistributedlockingtoensurethatthesamevirtualmachineisnotpoweredonbymultipleserversatthesametime.Ifaphysicalserverfails,theon-disklockforeachvirtualmachinecanbereleasedsothatvirtualmachinescanberestartedonotherphysicalservers.

VMFSalsofeaturesenterpriseclasscrashconsistencyandrecoverymechanisms,suchasdistributedjournaling,crashconsistentvirtualmachineIOpath,andmachinestatesnap-shots.Thesemechanismscanaidequickroot-causeanalysisandrecoveryfromvirtualmachine,physicalserver,andstoragesubsystemfailures.

VMFSalsosupportsRawDeviceMapping(RDM).RDMprovidesamechanismforavirtualmachinetohavedirectaccesstoaLUNonthephysicalstoragesubsystem(FiberChanneloriSCSIonly).RDMisusefulforsupportingtwotypicaltypesofapplica-tions:

• SANsnapshotorotherlayeredapplicationsthatruninthevirtualmachines.RDMbetterenablesscalablebackupoffload-ingsystemsusingfeaturesinherenttotheSAN.

• AnyuseofMicrosoftClusteringServices(MSCS)spansphysicalservers:virtual-to-virtualclustersaswellasphysical-to-virtualclusters.ClusterdataandquorumdisksshouldbeconfiguredasRDMsratherthanasfilesonasharedVMFS.

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ThevirtualSCSIdisksinsidethevirtualmachinesareprovi-sionedfromDatastoreelementsinthedatacenter.ADatastoreislikeastorageappliancethatservesupstoragespaceforvirtualdisksinsidethevirtualmachinesaswellasstoringthevirtualmachinesthemselves.AsshowninFigure1-10,avirtualmachineisstoredasasetoffilesinitsowndirectoryintheDatastore.Avirtualdiskinsideeachvirtualmachineislocatedoneormorefilesinsidethedirectory.Asaresult,avirtualdiskcanbeeasilymanipulated(copied,moved,backed-up,andsoon)justlikeafile.Virtual disks can be “hot-added” to a virtual machine without powering it down .Inwhichcase,anewvirtualdiskfileiscreatedoranexistingvirtualdiskfileisassociatedwiththevirtualmachine.

TheDatastoreprovidesasimplemodeltoallocatestoragespacefortheindividualvirtualmachineswithoutexposingthemtothecomplexityofthevarietyofphysicalstoragetech-nologiesavailable,suchasFiberChannelSAN,iSCSISAN,DirectAttachedStorage,andNAS.

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Figure 1-11: Raw Device Mapping

ESXServercommunicateswithotherresourcesthroughitsHostAgentusingtheVMwareInfrastructureAPI(VIAPI).UsingtheVMwareInfrastructureSDK,bothVMwareandthird-partysoftwarecancollectinformationfromandmanageESXServerthroughtheVIAPI.

Asdiscussedearlier,theVMwareHAagentprovidesa“heart-beat”suchthatwhenitisabsent,itsignalsotherphysicalserversintheClustertorestartthevirtualmachinesthathavegonedownwiththehostingserver.TheVMwareHAagentresidesoneachphysicalserverandcommunicateswiththeHostAgenttoconstantlycheckonthehealthoftheserver.

Figure 1-12: How Consolidated Backup Works

eSX Server external Interfacing ComponentsESXServerisavirtualizationlayerthatabstractstheprocessor,memory,storage,andnetworkingresourcesofaphysicalserverintomultiplevirtualmachinesthatrunside-by-sideinasecuredandisolatedmanner.ThereisonecopyoftheESXServerthatrunsoneachphysicalx86machine.Inthissection,onlythecomponentsofESXServerthatinterfaceswiththeoutsideworldaredescribed,seeFigure1-1�.Formoredetailinforma-tiononESXServer,pleaseconsultnumerousotherESXServertechnicaldocuments.

Figure 1-13: VMware ESX Server External Interfacing Components

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AnRDMcanbethoughtofasasymboliclinkfromaVMFSvolumetoarawLUN(seeFigure1-11).ThemappingmakesLUNsappearasfilesinaVMFSvolume.Themappingfile—nottherawLUN—isreferencedinthevirtualmachineconfigura-tion.

WhenaLUNisopenedforaccess,VMFSresolvestheRDMfiletothecorrectphysicaldeviceandperformsappropriateaccesschecksandlocking.Thereafter,readsandwritesgodirectlytotherawLUNratherthangoingthroughthemappingfile.

VMware Consolidated BackupVMwareInfrastructure’sstoragearchitectureenablesasimplevirtualmachinebackupsolution:VMwareConsolidatedBackup.Consolidated Backup provides an easy to use, centralized facility for agent-less backup of virtual machines .AsshowninFigure1-1�,ConsolidatedBackupworksinconjunctionwithathird-partybackupagentresidingonaseparatebackupproxyserver(notontheserverrunningESXServer)butdoesnotrequireanagentinsidethevirtualmachines.Thethird-partybackupagentmanagesthebackupschedule.ItstartsConsolidatedBackupwhenitistimetodoabackup.Oncestarted,ConsolidatedBackuprunsasetofpre-backupscriptstoquiescethevirtualdiskstotaketheirsnapshots.Itthenrunsasetofpost-thawscriptstorestorethevirtualmachinebacktonormaloperation.Atthesametime,itmountsthedisksnapshottothebackupproxyserver.Finally,thethird-partybackupagentbacksupthefilesonthemountedsnapshottoitsbackuptargets.Bytakingsnapshotsofthevirtualdisksandbackingthemupatanytimewithoutworryingaboutbackupwindowsorneedtoquiesceapplications,ConsolidatedBackupprovidesasimple,lessintrusiveandlowoverheadbackupsolutionforthevirtualenvironment.

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TheVirtualCenterAgent(VCAgent)issentbytheVirtualCenterManagementServerwhenamachinerunningESXServerisfirstaddedtobemanaged.VCAgentresidesoneachmachineandactsasthebrokerbetweenVirtualCenterManagementServerandtheESXServerthatitmanages.

TheVCAgentcommunicateswiththeHostAgentthroughtheVIAPIasshowninFigure1-1�.ItsmaintaskistooffloadsomeoftheVirtualCenterManagementServerfunctionsspecifictoonephysicalserver.ThisenablesVirtualCenterManagementServertoscaleupandmanageamuchlargernumberofphysicalserverswithoutdemandingaproportionalamountofcomputingpowerandnetworkbandwidth.SomeofthekeytasksperformedbyVCAgentare:

•RelayingandenforcingresourceallocationdecisionsmadeinVirtualCenterManagementServer(includingthosesentbytheVMwareDRSengine)

•PassingvirtualmachineprovisioningandconfigurationchangecommandstotheHostAgent

•PassingHostconfigurationchangecommandstotheHostAgent

•Monitoringandcollectingperformancestatistics,alarms,andeventsbycommunicatingwiththeHostAgentviatheVIAPI

•PassinginformationbacktotheVirtualCenterManagementServeronceacertainquantityofinformationiscollected.

VMotion

DRS

host and VMconfiguration

VI API

HAVirtualCenter

Management Server

ESX Server management

core services

distributedservices

useraccesscontrol

activedirectoryinterface

data

base

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rface

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VM provisioning

resources &virtual machine

inventorymanagement

taskscheduler

statisticslogging

alarms & eventsmanagement

activedirectoryserver

third-partyapplication

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VirtualCenterAgent

VMVM

HA

Host Agent

VI API

VirtualCenter Management Server architectureVirtualCenter Management Server provides a convenient centralized management cockpit for the data center . ItaggregatesphysicalresourcesfrommultipleESXServerinstal-lationsandpresentsacentralcollectionofsimpleandflexibleresourcesforthesystemadministratorwhenprovisioningvirtualmachinesinthevirtualenvironment.

Figure 1-14: VirtualCenter Management Server Components

Figure1-14showsthekeyfunctionalcomponentsoftheVirtualCenterManagementServer.TheyincludeUserAccessControl,CoreServices,DistributedServices,andinterfacestoexternalresources..

TheUserAccessControlallowsthesystemadministratortocreateandmanagedifferentlevelsofaccesstotheVirtualCenterfordifferentusers.Forexample,theremightbeauserclassthatmanagesconfiguringthephysicalserversinthedatacenterandtheremightbeadifferentuserclassthatmanagesonlyvirtualresourceswithinaparticularResourcePool.

CoreServicesarebasicmanagementservicesforavirtualdatacenter.Theyincludeservicessuchas:

•VMProvisioning–Guidesandautomatestheprovisioningofvirtualmachines

•HostandVMConfiguration–Allowstheconfigurationofhostsandvirtualmachines

BoththeVirtualCenterManagementServerandVMwareESXServercanbemanagedthroughtheVIAPIbyVMwareInfrastructuretoolsorthird-partytools.

ManagingESXServerdirectlyshouldbedonebyphysicalserveradministratorsonspecialcircumstancesonly.AllmanagementfunctionalitythatcanbedoneontheESXServercanalsobedoneinVirtualCenterManagementServer.

UsingtheVIClient,userscanmanageboththephysicalandvirtualresourcesofthedatacenter.WhenaccessingVirtualCenterManagementServer,asessionstartsafterauserisauthenticated.Afterauthentication,aviewoftheresourcesandvirtualmachinesthatbelongstotheuserispresented.Foraccessingavirtualmachineconsoledirectly,theVIClientfirstobtainsthevirtualmachinelocationfromtheVirtualCenterManagementServerthroughtheVIAPI.ItthenconnectsdirectlytotheappropriateESXServerandpresentstheappropri-atevirtualmachineconsole.

WithaWebbrowser,userscanmanagethevirtualresourcesandaccessthevirtualmachineconsole.UserscandosobyVirtualCenterfirstpointingtheWebbrowsertotheVIWebAccess.TheVIWebAccessmediatesthecommunicationbetweenthebrowserandVirtualCenterManagementServerthroughtheVIAPI.ToaccessthevirtualmachineconsolesthroughtheWebbrowser,userscanmakeuseofbookmarkscreatedbytheVirtualCenterManagementServer.Thebookmark

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•ResourceandVirtualMachineInventoryManagement–Orga-nizesvirtualmachinesandresourcesinthevirtualenviron-mentandfacilitiestheirmanagement

•StatisticsandLogging–Logsandreportsontheperformanceandresourceutilizationstatisticsofdatacenterelements,suchasvirtualmachines,hostsandclusters

•AlarmsandEventManagement–Tracksandwarnsusersonpotentialresourceover-utilizationoreventconditions

•TaskScheduler–SchedulesactionssuchasVMotiontohappenatagiventime

DistributedServices,suchasVMwareDRS,VMwareHA,andVMwareVMotion,aresolutionsthatextendthecapabilitiesofVMwareInfrastructuretothenextlevel.DistributedServicesallowtheconfigurationandmanagementofthesesolutionscentrallyfromVirtualCenterManagementServer.

VirtualCenterManagementServerhasfourkeyinterfaces:

•ESXServerManagement–InterfaceswiththeVCAgenttomanageeachphysicalserverinthedatacenter

•VMwareInfrastructureAPI–InterfaceswithVMwaremanage-mentclientsandthird-partysolutions

•DatabaseInterface–ConnectstoOracleorMicrosoftSQLServertostoreinformationsuchasvirtualmachineconfigura-tions,hostconfigurations,resourceandvirtualmachineinven-tory,performancestatistics,events,alarms,userpermissionsandroles

•ActiveDirectoryInterface–ConnectstoActiveDirectorytoobtainuseraccesscontrolinformation

Accessing the Virtual Data CenterUserscanmanagetheVMwareInfrastructuredatacenteroraccessthevirtualmachineconsolethroughthreedifferentmeans:theVIClient,WebAccessthroughaWebbrowser,orterminalservices(suchasWindowsTerminalServicesorXterm).

Figure 1-15: VMware Infrastructure Access and Control

Host

VI Web Access

VirtualCenterAgent

VMVM

HA

VIAPI

WindowsTerminal Services/

Xterm

Web

bro

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• VirtualCenter mgmt access

• host &vm config. & control access

• vm console access

• VirtualCenter mgmt access

• host &vm config. & control access

• vm console access

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• vm console access

firstpointstotheVIWebAccess.VIWebAccessresolvesthephysicallocationofthevirtualmachinethenredirectstheWebbrowsertotheappropriateESXServerwherethevirtualmachineresides.

Users,ofcourse,canaccesstheirvirtualmachineconsoleexactlythesamewaythattheyaccessthephysicalmachinebyusingstandardtoolssuchasWindowsTerminalServicesorXterm.

ConclusionOfallthevirtualizationsolutionsinthemarket,onlyVMwareInfrastructureisarchitectedfromthegrounduptoenablecustomerstobringthebenefitsofvirtualizationtotheentireenterpriseplatform,includingserver,storageandnetworkingsystems.VMwareInfrastructurenotonlyenablescustomerstobuildanentirevirtualdatacenterthatmatchesthecapabilitiesavailableinthephysicalworld,butitgoesonestepfurtherbyofferingtheflexibilityandcontrolthatisphysicallycost-prohibi-tiveorimpossible.

Withawholesuiteofcomplementaryvirtualizationandman-agementservicessuchasvirtualVMwareVMotion,VMwareDRS,VMwareHAandVMwareConsolidatedBackup,VMwareInfrastructureistheonlyofferingthatdeliversacompletesolutionratherthanpiece-mealapproachforcustomerstobuildadatacenterinavirtualenvironment.

Initsthirdgenerationsincebeingthefirst-evertovirtualizethex86platform,VMwareInfrastructurehasdevelopedalargethird-partysolutionsecosystemandenjoysindustry-widehardwareandsoftwarecertificationsupport.Sinceinceptionin1998,ithasbeenproductiontestedanddeployedinsomeofmostdemandingandlargestITproductionenvironments.VMwareInfrastructureistheonlyvirtualizationsolutionreadyforenterprise-widedeploymentbycorporateIT.

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Host

VI Web Access

VirtualCenterAgent

VMVM

HA

VIAPI

WindowsTerminal Services/

Xterm

Web

bro

wse

rV

I Clie

nt

• VirtualCenter mgmt access

• host &vm config. & control access

• vm console access

• VirtualCenter mgmt access

• host &vm config. & control access

• vm console access

VirtualCenterManagement Server

ESX Server management

distributed services

core servicesuser

accesscontrol

activedirectoryinterface

data

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VI API

• vm console access