vmware infrastructure architecture overview vmware® infrastructure is the industry’s first full...
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VMware Infrastructure Architecture Overview
W H I T E P A P E R
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VMware white paper
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
VMware Infrastructure
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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
VirtualCenterdatabase
VM provisioning
resources &virtual machine
inventorymanagement
taskscheduler
statisticslogging
alarms & eventsmanagement
activedirectoryserver
third-partyapplication
Host
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
wse
rV
I Clie
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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
VirtualCenterManagement Server
ESX Server management
distributed services
core servicesuser
accesscontrol
activedirectoryinterface
data
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Host Agent
VI API
• 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
base
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rface
Host Agent
VI API
• vm console access