超融合基础设施的基础知识-1

Gorilla

Guideto…®

The

TheEdition!

2018

FundamentalsofHyperconvergedInfrastructure

InsideThisGuide:

•LearnabouttheITchallengesthatremainin

apost-virtualizationdatacenter

•Gainanunderstandingofallthathyperconvergedinfrastructurehastooffer

•Zeroinonthebusinessbenefitsthatcome

withtheadoptionofhyperconvergence

JamesGreen,ScottD.Lowe,DavidM.Davis

ActualTechMedia

InPartnershipWith

HelpingYouNavigate

TheTechnologyJungle!

TheGorillaGuideTo…

TheFundamentalsof

Hyperconverged

Infrastructure

Authors

JamesGreen,ActualTechMedia

ScottD.Lowe,ActualTechMedia

DavidM.Davis,ActualTechMedia

Editor

HilaryKirchner,DreamWriteCreative,LLC

LayoutandDesign

ScottD.Lowe,ActualTechMedia

Copyright©2017byActualTechMedia.Allrightsreserved.Noportionofthisbookmaybereproducedorusedinanymannerwithouttheexpresswrittenpermissionofthepublisherexceptfortheuseofbriefquotations.TheinformationprovidedwithinthiseBookisforgeneralinformationalpurposesonly.Whilewetrytokeeptheinformationup-to-dateandcorrect,therearenorepresentationsorwarranties,expressorimplied,aboutthecompleteness,accuracy,reliability,suitabilityoravailabilitywithrespecttotheinformation,products,services,orrelatedgraphicscontainedinthisbookforanypurpose.Anyuseofthisinformationisatyourownrisk.

ActualTechMedia

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EnteringtheJungle

Chapter1:VirtualizationintheModernDataCenter.......7

WhatIsVirtualization?

7

HowVirtualizationWasSupposedtoChangeIT

10

OperationalEfficiency

10

TechnologyAgility

11

AdvancedAvailabilityFeatures

11

Virtualization-InducedChallenges

12

VirtualizationisaCommodity

15

Chapter2:IntroductiontoHyperconvergence

17

WhatIsHyperconvergence?

17

HowHyperconvergenceCametoBe

19

LeveragingVirtualization

20

SingleVendorAcquisitionandSupport

21

LowerCostofOwnership

22

NextUp

22

Chapter3:BenefitsofHyperconvergence

23

ManagementEfficiency

23

DataEfficiency

24

HighAvailability

25

Scalability

27

DataProtection

28

ComparingTraditionalStorageandHyperconvergence

29

Chapter4:HyperconvergenceArchitecture

30

VirtualStorageAppliances

31

Hypervisor-EmbeddedStorageVirtualization

33

WhichIsBetter?

34

Chapter5:HyperconvergenceUseCases

35

ServerVirtualization

36

HyperconvergenceforServerVirtualization

36

WhatThisMeans

37

EdgeComputing

37

PhysicalSpace

39

ITStaff

40

VirtualDesktopInfrastructure

41

DisasterRecovery

41

Chapter6:ThinkingDifferentlyAboutIT

43

SinglePointofAdministration

43

Pre-Hyperconvergence

43

HowHyperconvergenceHelps

43

SinglePointofAcquisitionandSupport

44

Pre-Hyperconvergence

44

HowHyperconvergenceHelps

45

HighAvailabilityforStorage

45

DisasterRecovery

46

BackupandReplication

46

SingleInterfaceforDR

47

ReducedTotalCostofOwnership

47

That’saWrap

48

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Cp9pter1

VirtualizationintheModernData

Center

Consumertechnologyisconstantlychanging,andthesamegoesforthetechnologyusedindatacentersaroundtheworld.Justasconsumersarenowabletobuyasinglesmartphonedevicetodojustaboutanythingtheycandreamup,ITbuyerscannowacquireasingledeviceorsolutionforjustaboutanyinfrastructureservicetheyneed.

Thissingledevice/solutionconceptismadepossiblebyfasterandfasterserverhardware,virtualization,andhyperconvergence.

Inthisbook,we’llstartbybrieflyintroducingvirtualizationasaconcept,incaseit’snewtoyou,andthendiscussthestateofvirtualizationtoday.Lateron,we’llintroduceyoutohyperconvergenceandthewayitsolvesmanyofthechallengesthatvirtualizationintroduces.Bytheendofthebook,you’llunderstandthevarioustypesofhyperconvergencearchitecturesandwhatsortsofusecasesbenefitmostfromhyperconvergence.

AlreadyaVirtualizationExpert?

Ifyoualreadyhaveagoodgraspofvirtualizationandtheadvantagesitbrings,aswellasthechallengesitintroduces,feelfreetoskipthischapterandmoveontoChapter2,“IntroductiontoHyperconvergence.”

Ifyouhaven’tstartedtovirtualizeyourserverinfrastructure,orifyou’vestartedvirtualizingbuthaven’tyetachieved100%virtualization,readthischapterbeforemovingon.Inthischapter,you’lllearnaboutvirtualizationandbecomemotivatedto“virtualizeeverything,”asisthenormatmoreandmorecompanies.

WhatIsVirtualization?

IfyouworkinanITorganization,surelyyouhaveatleastheardaboutvirtualization.Virtualizationhaschangedtheworldoftechnologyforlargeenterprises,smallandmedium-sizebusinesses(SMBs),ITpros,andevenmanyconsumers.

Usingsoftware,virtualizationabstractsawaysomethingthatwastraditionallyphysicalandrunsitasvirtual.

Butwhatdoesthatmean,virtual?Withservervirtualization,softwareemulateshardwareforthepurposeofabstractingthephysicalserverfromtheoperatingsystem.Thisabstractionisdoneusingaspecialpieceofsoftwarecalledahypervisor.Thehypervisoreitherrunsontopoforinsideanoperatingsystem(suchasWindowsServeroraLinuxvariant)andallowsyoutorunvirtualizedserversontopofthathypervisor.Thosevirtualizedserversaretypicallycalledvirtualmachines,orVMs.ItisinsidetheVMsthatyoucaninstalljustaboutanyguestoperatingsystem,applications,anddatathatyouchoose.

Whatcompanieslargeandsmallcandowithvirtualizationistotaketheirexistingphysicalservers,virtualizethem,andruntheminsideVMsthatrunontopofasinglehostserver.Theresultofthistypeofvirtualizationisthatcompaniescanconsolidatemanyphysicalserversontofarfewerphysicalservers.Infact,someorganizationscanconsolidatealltheirVMsontoasinglehost.Orpreferably,asbestpracticeswoulddictate,theycanrunalltheirvirtualmachinesacrosstwohostsinacluster,storingvirtualmachineimagesonsharedstorage,sothatonehostcouldtakeoverfortheotherhostintheeventoffailure.

VirtualizationintheModernDataCenter8

Insteadofusingthedictionarydefinitionofabstractiontodescribevirtualization,mostadminsdescribeitwithphrasessuchas:

•Virtualizationallowsyoutorunmuch,muchmoreonasinglephysicalserver(host)thaneverbefore.

•VirtualizationallowsITorganizationstodomorewithless.

•Virtualizationiswhenyourunyourserversontopofsoftware-basedvirtualmachinesinsteadofonhardwaremachines.

AsyoucanseeinFigure1-1,withasinglephysicalserver(havingitsownCPU,memory,andstorageI/Oresources),youarelayeringahypervisorontopinplaceofthetypicalserveroperatingsystem.Then,ontopofthathypervisor,youarerunning2VMs,eachwithitsownCPU,memory,andI/Oresources,sothatyoucaninstallyourownguestoperatingsystemtorunapplicationsandstoragecompanydata.

Figure1-1:Servervirtualizationdiagram

ITprofessionalshavelookedtovirtualizationtosavethemfromsomeseriouschallenges.Namely,virtualizationhashelpedtoovercomeavailabilitychallengesandincreaseoperationalefficiency.

VirtualizationintheModernDataCenter9

HowVirtualizationWasSupposedto

ChangeIT

It’sgreattolookatservervirtualizationfromtheperspectiveofthebusinessandshowallthemoneythatcanbesaved.Afterall,inmanycases,someofthatmoneysavedcanbeusedintheITorganizationforotheruses.

Butwhatifyoulookatservervirtualizationfromtheperspectiveofthestaffwhoadministerstheinfrastructure?Howdoesservervirtualizationchangethedailylifeoftheinfrastructureadmin?

OperationalEfficiency

Adminsarecontinuallypushedtoaddmoreandmoreapplicationsorsupportmoreusersanddevices.However,rarelyaretheyofferedanyadditionalresourcestomanageandsupportalltheadditionalinfrastructurerequired.Noadditionaladministrativestaff,noadditionalbudget,andinmanycases,notevenanyadditionalinfrastructuretoruntheapplications.

Inotherwords,adminsaresimplyexpectedto“domorewithwhatyouhave…orwithless.”ThisisespeciallytrueatSMBs,whichhaveinherentlysmallerbudgetsthanlargeenterprises.

Servervirtualizationisoneofthefewsolutionsthatcanactuallyallowadminstoaccomplishthis“do-more-with-less”goal.

Servervirtualizationoffersfargreaterefficiencyinadministrationbecause:

•Virtualizedservers(andVMs)areportable.Theycaneasilybemovedfromoneservertoanother,andvirtualhardwarecanberesizedwhennewresourcesareneeded—theycanbeclonedorcopiedtoaddmoreVMs.

VirtualizationintheModernDataCenter10

•Virtualizedservers(VMs)areallmanagedfromasinglecentralizedmanagementinterface.Monitoring,performancemanagement,andtroubleshootingareallfarmoreefficientthanhavingmanyphysicalserverstocontendwith.

•Byhavingmanyfewerservers,adminshavefewerserverstokeepcurrent.Thisisespeciallyhelpfulwhenserversneedupdating(bothhardwareandsoftware)orwhentroubleshooting,shouldtheunexpectedoccur.

TechnologyAgility

EndusersexpectadminstobeabletobringupnewapplicationsorVMswithinminutesandensurethatapplicationsnevergodown.

Meetingthoseexpectationsisnexttoimpossiblewithtraditionalphysicalservers;however,withservervirtualization,adminscanmeetthemeasily.

Withservervirtualization,VMsarehardwareindependentandcanbeeasilybacked-up,replicated,restored,cloned,ormovedfromoneserverorsitetoanother.

ServervirtualizationallowsadminstocreatealibraryofVMimagesandspinupnewVMswheneverneeded.

Finally,VMscaneasilybemovedfromservertoserverorsitetositewithwithoutdowntimeinmostcases.

AdvancedAvailabilityFeatures

Servervirtualizationalsoallowsadministratorstoleveragemoreadvanceddatacenterfunctionalitythanwouldeverbepossiblewithapurelyphysicaldatacenter.Herearesomeexamples:

•Virtualizationbackup.Virtualizationbackupmakesdataprotectioneasy,becauseitcaneasilybackuponlythechangedblocksofaVM’sdiskstorageandsendthemtotape.Protected

VirtualizationintheModernDataCenter11

VMscanberecoveredontootherserversasneeded,andtheunderlyinghardwareisabstracted.Asaresult,VMscaneasilyberestoredontoaverydifferentphysicalserverthantheoriginal.

•Replication.ReplicationcanbedoneallinsoftwareforanyVMorgroupofVMsthatneedoffsitedataprotection.

•Balancingresourceconsumption.ResourceconsumptiononthevirtualinfrastructurecanbedynamicallybalancedwithintheclustertoensurethateveryVMgetstheresourcesitneedstorunitsapplications.

Virtualization-InducedChallenges

Asyou’velearnedabove,servervirtualizationimmediatelyofferstheITorganizationnumerousbenefits.However,datacentersrarelyshrink.Datacenterfootprintstendtogrowovertime,creatingtheneedtoaddmorevirtualizationhosts(physicalservers)toprovideresourcestorunmoreVMs.Astheinfrastructureandapplicationcriticalitygrows,sodoestheneedforhighavailability.Availabilityassuranceisoneofthemostpopularfeaturesofmostservervirtualizationhypervisors.Withservervirtualization,whenaphysicalserverfails,allVMsthatwererunningonitcanbeautomaticallyrestartedonsurvivinghosts.

Whilehighavailabilityinservervirtualizationmaybereadily

availableandeasytoimplement,thesameisnottrueforhighavailabilityforstorage.

Withvirtualserverhost-to-hostfailoverrequiringsharedstoragetowork,datacenterarchitectsmustutilizeasharedstoragesystem(SANorNAS)tostoretheVMdiskfileson.Highavailabilityforservervirtualizationmitigatesahostfailureinshortorder,butoffersnothingtomitigateanypossiblefailureofthesharedstorage.Withsharedstorageoftenbeingcomplexandexpensive,thearchitecturethatmanyservervirtualizationdesignsendupwithiswhat’scalledthe“3-2-1design”(alsoknownasthe“invertedpyramidofdoom”).

VirtualizationintheModernDataCenter12

The3-2-1design(showninFigure1-2)iswhen,forexample,youhave3hosts,2networkswitches(forredundancy),and1sharedstoragearraywherealldataisstored.Inthe3-2-1design,thesharedstoragearrayisthesinglepointoffailure,meaningthatifthesinglesharedstoragearrayfails,everythingelseintheinfrastructuregoesdownaswell.

Figure1-2:The3-2-1infrastructuredesign

Unfortunately,toomanyorganizationsarestuckinthe3-2-1designevenasthenumberofserversintheirinfrastructuregrowswellbeyondthreehosts.Evenlargecompanieswith50ormorehostsstillusethis“invertedpyramidofdoom”infrastructuredesignsimplybecausetheycan’taffordthecostorhandlethecomplexitytomovebeyondit.That’sbecause,tomovetoaredundantstorageinfrastructurewhereyoudon’thavethesharedstorageasthesinglepointoffailure,youmustimplementaninfrastructuredesignsimilartotheoneshowninFigure

1-3.

VirtualizationintheModernDataCenter13

Figure1-3:Virtualinfrastructurewithhighavailabilityforstorage

Withthisdesign,youimplementaredundantSANorNASarray.Whenyoudoso,thatarraycaneliminatethe“1”inthe3-2-1designarchitectureandensurethatcriticalapplicationsrunninginthevirtualinfrastructuredon’tgodownshouldthesharedstoragesufferafailure.

Thefirstchallengeinthisinfrastructureadditionis,ofcourse,thecost.Buyingsharedstoragetobeginwithisachallengeformanybusinesses.Theideaofbuyingredundantsharedstorageandpayingessentiallydoublethepriceispainful.

Thesecondchallengewiththisdesignisthetremendousandundesiredcomplexitythatitbringstothedatacenter.

Infrastructureadminscommonlywearmanydifferenthats.Herearejustsomeofthethingsanaverageinfrastructureadminmighthavetodealwith:

•Hypervisoradministration

•Networkadministrationwithfullredundancy

•SAN(e.g.,targets,LUNs,multipathing)orNASadministration

•Hardwarecompatibilitylists(HCL)management

•Patchingandupdatingmultiplesystemsandrelatedfirmware

VirtualizationintheModernDataCenter14

•Dealingwithmultiplesupportgroupswhenunexpectedtroubleoccurs,whichusuallyresultsinfinger-pointingandinefficiency

•Maintainingmultiplemaintenancecontracts,whichiscostlyandtime-consuming

VirtualizationIsaCommodity

We’repushingintothethirddecadeofx86virtualizationbeingavailabletoconsumers,andintotheseconddecadeofservervirtualizationbeingutilizedinthemainstreamdatacenter.Atthispoint,mostdatacenterarchitectsjustexpectvirtualization.Manyorganizationshavea“virtualfirst”policy,whichessentiallydictatesthatallworkloadsshouldbevirtualizedunlessthere’sagoodreasontodootherwise.

Acceptingvirtualizationasastandarddatacenterpracticeisgreat,anditprovidestremendousbenefitstoITorganizationsandtothebusinessestheyserve.However,thecomplexitythateatsawayatgrowingvirtualizedenvironmentscanstarttonegatesomeoftheeffectsthatvirtualizationwasadoptedforinthefirstplace.

Whatmoderndatacenterstrulyneedisasolutionthatoffersthemallthebenefitsofvirtualizationwithoutallthecomplexitiesthatcomealongwithvirtualization,oncethevirtualinfrastructuregrowsandadvancedfunctionalityisadded(suchashighavailabilityforstorage).Hyperconvergenceisthatsolution,andyou’regoingtolearnaboutthatnext.

VirtualizationintheModernDataCenter15

UpNext

Youhaveagoodunderstandingofwhatvirtualizationisandhowitissupposedtohelpyourcompany.Butyou’vealsojustbeguntorealizethatevenwhilevirtualizationsolvessomebigproblemsinthedatacenter,italsointroducessomenewones.

Inthenextchapter,you’lllearnaboutadatacenterarchitecturecalledhyperconvergencethatleveragesvirtualizationandsoftware-definedstorage(SDS)totakeefficiency,agility,andcostsavingstothenextlevel.

VirtualizationintheModernDataCenter16

Cp9pter2

IntroductiontoHyperconvergence

Ifyouhaven’tbeenlivingunderarock,it’sverylikelythatyou’veheardthetermhyperconvergenceoverthepastcoupleofyears.JustlikealmostallITbuzzwords,ithasbecomenotoriousforbeingoverusedandunder-defined.BeforediscussingthevalueofhyperconvergenceandhowitcantransformITinyourorganization,youneedtounderstandtheterm.Solet’sdefinethetermhyperconvergenceandbrieflydiscusstheinceptionanddriversforit.

WhatIsHyperconvergence?

Atthehighest,mostabstractlevel,hyperconvergencecanbeunderstoodtobethecombination(orconvergence)ofmanypotentiallydisparateplatformsintoasingleplatform.Inrelationtothephysicalhardware,thismeansplacingcompute(CPUandmemory)andstorage(spinningdiskandsolid-statedrives[SSDs])intoasingleserver.Fromasoftwareperspective,thismeansthatattheveryleast,allcomponentsofthesystemaremanagedfromacommoninterface.Dependingontheoffering,thismaybeacustomuserinterfacebuiltbythemanufacturer,oritcouldbeanadd-onorextensiontotheexistinghypervisormanagementsoftware.

RememberfromChapter1thatthehypervisoristhesoftwarethatallowsmultiplevirtualmachines(VMs)torunonasinglepieceofphysicalhardware.

Whyisitcalledhyperconvergence?

Thewordhyperconvergencestemsfromthe

combinationofthewordshypervisor+convergence=

hyperconvergence.

Itsdefinitionstemmedfromanattempttodifferentiatefromthetrendofconvergenceingeneral.Ithastakenonalifeofitsownandnowissynonymouswithcombiningmanypotentiallydisparateplatformsinto

asingleplatformforrunningvirtualmachines(VMs).

Acommonlyunderstooddefinitionofhyperconvergencestatesthatitis“aplatformthatpoolsdirectattachedstorageandeliminatestheneedforastoragearray.”Whilethisistrue,itdoesn’ttellthewholestory.Physicalhardwareisanimportantpieceofthepuzzle,butthegranderpictureofhyperconvergenceisreallyfocusedonthesimplifiedmanagementofthedatacenterinfrastructure.Hyperconvergenceaimstoeliminatesiloesofmanagement.

Acharacteristicfeatureofhyperconvergenceisthatitscalesoutinpredictable,finiteportions.Theseportionsareoftenrepresentedasbuildingblocks.Asanadminaddsbuildingblocks(alsocallednodes,bricks,orvariousothertermsthatmean“asingleunit”)tothecluster,alltherelevantinfrastructurecomponentsscaletogether.

Thehyperconvergedinfrastructure(HCI)modelisincontrasttoanolderdatacentermodelwherestoragecapacitymightbeaddedatonepoint,andthenadditionalRAM,CPUnodes,andsoonwouldbeaddedafewmonthsdowntheroad.

Withhyperconvergence,allresourcescanscaleatonce.However,itisstillpossibletoscaleresourcesindependently,ifneeded.

IntroductiontoHyperconvergence18

HowHyperconvergenceCametoBe

Thestoryofhowhyperconvergencecametobeisreallyachapterinabiggerstoryaboutthecyclicalnatureofthedatacenter.Asyoumayhavenoticed,thedatacentertendstoevolveinacyclicalfashion.Whatwasoncethestandardiscontinuallyimproveduponuntilnearlytheoppositearchitectureisthestandard.Thenitisimprovedonagainandlooksverymuchlikeitusedtoadecadeago.

Anexampleofthiscyclicalnatureisend-usercomputing.Astechnologydevelopedtoallowmultipleuserstoshareasinglecomputer,usersconnectedwith“dumb”devicesthatweresimplyadisplayandcontrolstomanipulatethecomputerrunninginthedatacenter.Astechnologyevolvedfurther,thedesktopcomputerbecamethestandardforendusers,andeveryonehadoneontheirdesk.Today,manyorganizationschoosetousevirtualdesktopandthinorzeroclientdevicesforend-userworkstations.Thislooksverymuchliketheterminalserverarchitectureofthepast,butwithanewbreathoflife.

Thehyperconvergencestoryisthesame.Onceuponatime,inadatacenteracoupleofdecadesago,physicalserversranasingleworkload.Theyhadanoperatingsystemandlocallyattachedstoragewheretheoperatingsystemandapplicationswereinstalled.Eachoftheseserverswasmanagedindividually.

Then,roughlyadecadeago,theconceptofasharedstoragearraywasbroadlyadoptedtoallowformoreefficiencyandutilization.Whileefficiencywasrealized,themanagementofthisinfrastructurebecamemorecomplex.

Hyperconvergenceisthecyclicalreturntodirect-attachedstorage,withtheimprovementbeingthedistributednatureofthatstorage.Inhyperconvergence,software-definedstorage(SDS)technologyallowsthedirect-attachedstoragetobepooledandmanagedasifitwassharedstorage.Leveragedintandemwithvirtualization,thisarchitectureallowsfortenstohundredsofworkloadstorunonahandfulofphysicalservers,andmanagingthemisabreeze.

IntroductiontoHyperconvergence19

LeveragingVirtualization

Speakingofvirtualization,wemustnotforgetthatvirtualizationisthecatalystthatallowsthecreationofhyperconvergedinfrastructure.Withoutvirtualizationsoftware(bothcomputevirtualizationandstoragevirtualization),thehyperconvergencemodelwouldnotbepossible.

YoualreadysawinChapter1whythecaseforservervirtualizationissostrong.Now,let’slookathowcombiningahypervisorwithhypervisor-embeddedstoragecantakevirtualizationtothenextlevel.

Byitsverynature,virtualizationofanykindabstractsaresourcefromaconsumer.Inthestorageportionofhyperconvergence,eachserverintheclusterhasagivenamountofdirect-attachedstorage.Thatmeansthatthedisksareconnectedtoastoragecontrollerinsideaparticularserver.Thoseserversareallconnectedbyanetworkfabric.Today,thatnetworkfabricislikelyIPover1or10GbE.Thefaster,thebetter.However,costisalwaysafactor.Theservershavedirect-attachedstorageandyetcansharedataamongthemselves.

OnelayeruponthelogicalstorageinfrastructurestacksitstheSDStechnology.SDSisdeliveredinvariousformsandisoutsidethescopeofthissection;sufficeittosaythatthisiswherestoragevirtualizationtakesplace.

Software-DefinedStorage

Foranythingtobedubbed"software-defined,"itmusthaveafewcharacteristics.First,itinvolvessomelevelofabstractionfromtheunderlyingresource.Additionally,theresourceisadministeredandmanagedviapolicies.Thispolicy-drivenapproach(asopposedtoanimperativeone)iswhatmakessoftware-defined[anything]sopowerful.

Inthecaseofstorage,asoftware-definedapproachlikelyimpliesstoragevirtualizationaswellaspolicy-basedmanagementofprovisioning,deduplication,replication,snapshotting,thinprovisioning,andbackups.

IntroductiontoHyperconvergenceS0

TheSDSlayerconsumestheunderlyingphysicalstorageandprovidesittotheworkloadthatwillconsumeit.Inmostcases,thisisaVM.Thisisthekeypointtounderstandaboutvirtualizationanditsroleinhyperconvergence:theworkload(theVMinthisexample)isunawareof,andindifferentto,theunderlyingresourceitisconsuming.Itjustgetswhatitneedsfromthevirtualization/abstractionlayer.

ThisexplainshowaVMrunninganywhereintheclustercanleveragestoragethatislocaltothenodeit’srunningonorstoragethatisremote(residingonanothernode);itdoesn’tknoworcarewherethedataisstored.

Themarriageofcomputeandstoragebybuildingaplatformthat