cma. tca srinivasa prasad computing basics.pdf · tca srinivasa prasad 5. 6 architecture •the...

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CMA. TCA Srinivasa Prasad+91 947 770 [email protected]

09/12/17 CMA. TCA Srinivasa Prasad

CloudComputing

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WhatisCloudComputing?

• CloudComputingisageneraltermusedtodescribeanew

classofnetworkbasedcomputingthattakesplaceoverthe

Internet,

– basicallyasteponfromUtilityComputing

– acollection/groupofintegratedandnetworkedhardware,

softwareandInternetinfrastructure(calledaplatform).

– UsingtheInternetforcommunicationandtransport

provideshardware,softwareandnetworkingservicesto

clients

• Theseplatformshidethecomplexityanddetailsofthe

underlyinginfrastructurefromusersandapplicationsby

providingverysimplegraphicalinterfaceorAPI(Applications

ProgrammingInterface).09/12/17 CMA. TCA Srinivasa Prasad

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WhatisCloudComputing?

• Inaddition,theplatformprovidesondemand

services,thatarealwayson,anywhere,

anytimeandanyplace.

• Payforuseandasneeded,elastic

– scaleupanddownincapacityandfunctionalities

• Thehardwareandsoftwareservicesare

availableto

– generalpublic,enterprises,corporationsand

businessesmarkets


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CloudSummary

• Cloudcomputingisanumbrellatermusedtoreferto

Internetbaseddevelopmentandservices

• Anumberofcharacteristicsdefineclouddata,

applicationsservicesandinfrastructure:

– Remotelyhosted:Servicesordataarehostedonremote

infrastructure.

– Ubiquitous:Servicesordataareavailablefromanywhere.

– Commodified:Theresultisautilitycomputingmodel

similartotraditionalthatoftraditionalutilities,likegas

andelectricity- youpayforwhatyouwouldwant!


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Architecture

• Thearchitecturebehindcloudcomputingisa

massivenetwork.

• Thecloudcomputinginfrastructureconsistsof

reliableservices.

• TheCloudappearsasasinglepointofaccess

forallthecomputingneedsofconsumers.

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CloudArchitecture


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WhatisCloudComputing

9Adopted from: Effectively and Securely Using the Cloud Computing Paradigm by peter Mell, Tim Grance

• Sharedpoolofconfigurablecomputingresources

• On-demandnetworkaccess

• ProvisionedbytheServiceProvider09/12/17 CMA. TCA Srinivasa Prasad

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CloudComputingCharacteristics

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Common Characteristics:

Low Cost Software

Virtualization Service Orientation

Advanced Security

Homogeneity

Massive Scale Resilient Computing

Geographic Distribution

Essential Characteristics:

Resource Pooling

Broad Network Access Rapid Elasticity

Measured Service

On Demand Self-Service

Adopted from: Effectively and Securely Using the Cloud Computing Paradigm by peter Mell, Tim Grance


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CloudServiceModels

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Software as a Service (SaaS)

Platform as a Service (PaaS)

Infrastructure as a Service (IaaS)

Google App Engine

SalesForce CRM

LotusLive

Adopted from: Effectively and Securely Using the Cloud Computing Paradigm by peter Mell, Tim Grance


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SaaSMaturityModel

12Source: Frederick Chong and Gianpaolo Carraro, “Architectures Strategies for Catching the Long Tail”

Level2:Configurableper

customer

Level3:configurable&

Multi-Tenant-Efficient

Level1:Ad-Hoc/Custom–OneInstancepercustomer

Level4:Scalable,Configurable

&Multi-Tenant-Efficient


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DifferentCloudComputingLayers

Application Service(SaaS)

Application Platform

Server Platform

Storage Platform Amazon S3, Dell, Apple, ...

3Tera, EC2, SliceHost, GoGrid, RightScale, Linode

Google App Engine, Mosso,Force.com, Engine Yard,Facebook, Heroku, AWS

MS Live/ExchangeLabs, IBM, Google Apps; Salesforce.comQuicken Online, Zoho, Cisco


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Services

Application

Development

Platform

Storage

Hosting

CloudComputingServiceLayersDescriptionServices – Complete business services such as PayPal, OpenID, OAuth, Google Maps, Alexa

Services

ApplicationFocused

InfrastructureFocused

Application – Cloud based software that eliminates the need for local installation such as Google Apps, Microsoft Online

Storage – Data storage or cloud based NAS such as CTERA, iDisk, CloudNAS

Development – Software development platforms used to build custom cloud based applications (PAAS & SAAS) such as SalesForce

Platform – Cloud based platforms, typically provided using virtualization, such as Amazon ECC, Sun Grid

Hosting – Physical data centers such as those run by IBM, HP, NaviSite, etc.


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BasicCloudCharacteristics

• The“no-need-to-know”intermsoftheunderlying

detailsofinfrastructure,applicationsinterfacewith

theinfrastructureviatheAPIs.

• The“flexibilityandelasticity”allowsthesesystems

toscaleupanddownatwill

– utilisingtheresourcesofallkinds

• CPU,storage,servercapacity,loadbalancing,anddatabases

• The“payasmuchasusedandneeded”typeofutilitycomputingandthe“alwayson!,anywhereandanyplace”typeofnetwork-basedcomputing.


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BasicCloudCharacteristics

• Cloudaretransparenttousersand

applications,theycanbebuiltinmultiple

ways

– brandedproducts,proprietaryopensource,

hardwareorsoftware,orjustoff-the-shelfPCs.

• Ingeneral,theyarebuiltonclustersofPC

serversandoff-the-shelfcomponentsplus

OpenSourcesoftwarecombinedwithin-

houseapplicationsand/orsystemsoftware.


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SoftwareasaService(SaaS)

• SaaSisamodelofsoftwaredeploymentwherean

applicationishostedasaserviceprovidedto

customersacrosstheInternet.

• Saasalleviatestheburdenofsoftware

maintenance/support

– butusersrelinquishcontroloversoftwareversionsand

requirements.

• Termsthatareusedinthissphereinclude

– PlatformasaService(PaaS)and– InfrastructureasaService(IaaS)


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Virtualization

• Virtualworkspaces:

– Anabstractionofanexecutionenvironmentthatcanbemade

dynamicallyavailabletoauthorizedclientsbyusingwell-defined

protocols,

– Resourcequota(e.g.CPU,memoryshare),

– Softwareconfiguration(e.g.O/S,providedservices).

• ImplementonVirtualMachines(VMs):

– Abstractionofaphysicalhostmachine,

– HypervisorinterceptsandemulatesinstructionsfromVMs,andallows

managementofVMs,

– VMWare,Xen,etc.

• ProvideinfrastructureAPI:

– Plug-instohardware/supportstructures Hardware

OS

App App App

Hypervisor

OS OS

Virtualized Stack1809/12/17 CMA. TCA Srinivasa Prasad

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VirtualMachines

• VMtechnologyallowsmultiplevirtual

machinestorunonasinglephysicalmachine.

Hardware

Virtual Machine Monitor (VMM) / Hypervisor

Guest OS(Linux)

Guest OS(NetBSD)

Guest OS(Windows)

VM VM VM

AppApp AppAppAppXen

VMWare

UML

Denalietc.

Performance: Para-virtualization (e.g. Xen) is very close to raw physical performance!


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VirtualizationinGeneral

• Advantagesofvirtualmachines:

– Runoperatingsystemswherethephysicalhardwareis

unavailable,

– Easiertocreatenewmachines,backupmachines,etc.,

– Softwaretestingusing“clean”installsofoperatingsystems

andsoftware,

– Emulatemoremachinesthanarephysicallyavailable,

– Timesharelightlyloadedsystemsononehost,

– Debugproblems(suspendandresumetheproblemmachine),

– Easymigrationofvirtualmachines(shutdownneededornot).

– Runlegacysystems!


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Whatisthepurposeandbenefits?

• Cloudcomputingenablescompaniesand

applications,whicharesysteminfrastructure

dependent,tobeinfrastructure-less.

• ByusingtheCloudinfrastructureon“payasused

andondemand”,allofuscansaveincapitaland

operationalinvestment!

• Clientscan:

– Puttheirdataontheplatforminsteadofontheirown

desktopPCsand/orontheirownservers.

– Theycanputtheirapplicationsonthecloudandusethe

serverswithinthecloudtodoprocessinganddata

manipulationsetc.2109/12/17 CMA. TCA Srinivasa Prasad

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Cloud-Sourcing

• WhyisitbecomingaBigDeal:

– Usinghigh-scale/low-costproviders,

– Anytime/placeaccessviawebbrowser,

– Rapidscalability;incrementalcostandloadsharing,

– CanforgetneedtofocusonlocalIT.

• Concerns:

– Performance,reliability,andSLAs,

– Controlofdata,andserviceparameters,

– Applicationfeaturesandchoices,

– InteractionbetweenCloudproviders,

– NostandardAPI– mixofSOAPandREST!

– Privacy,security,compliance,trust…2209/12/17 CMA. TCA Srinivasa Prasad

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SomeCommercialCloudOfferings


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CloudTaxonomy


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CloudStorage

• SeverallargeWebcompaniesarenowexploitingthe

factthattheyhavedatastoragecapacitythatcanbe

hiredouttoothers.

– allowsdatastoredremotelytobetemporarilycachedon

desktopcomputers,mobilephonesorotherInternet-

linkeddevices.

• Amazon’sElasticComputeCloud(EC2)andSimple

StorageSolution(S3)arewellknownexamples

– MechanicalTurk


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AmazonSimpleStorageService(S3)

• UnlimitedStorage.

• Payforwhatyouuse:

– $0.20perGByteofdatatransferred,

– $0.15perGByte-Monthforstorageused,

– SecondLifeUpdate:

• 1TBytes,40,000downloadsin24hours- $200,


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UtilityComputing– EC2

• AmazonElasticComputeCloud(EC2):

– Elastic,marshal1to100+PCsviaWS,

– MachineSpecs…,

– Fairlycheap!

• PoweredbyXen– aVirtualMachine:

– DifferentfromVmwareandVPCasuses“para-virtualization”where

theguestOSismodifiedtousespecialhyper-calls:

– HardwarecontributionsbyIntel(VT-x/Vanderpool)andAMD(AMD-V).

– Supports“LiveMigration”ofavirtualmachinebetweenhosts.

• Linux,Windows,OpenSolaris

• ManagementConsole/AP


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EC2– TheBasics

• LoadyourimageontoS3andregisterit.

• BootyourimagefromtheWebService.

• Openuprequiredportsforyourimage.

• ConnecttoyourimagethroughSSH.

• Executeyouapplication…


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OpportunitiesandChallenges

• Theuseofthecloudprovidesanumberof

opportunities:

– Itenablesservicestobeusedwithoutanyunderstanding

oftheirinfrastructure.

– Cloudcomputingworksusingeconomiesofscale:

• Itpotentiallylowerstheoutlayexpenseforstartupcompanies,as

theywouldnolongerneedtobuytheirownsoftwareorservers.

• Costwouldbebyon-demandpricing.

• VendorsandServiceprovidersclaimcostsbyestablishingan

ongoingrevenuestream.

– Dataandservicesarestoredremotelybutaccessiblefrom

“anywhere”.


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OpportunitiesandChallenges• Inparalleltherehasbeenbacklashagainstcloudcomputing:

– Useofcloudcomputingmeansdependenceonothersandthatcould

possiblylimitflexibilityandinnovation:

• TheothersarelikelybecomethebiggerInternetcompanieslikeGoogle

andIBM,whomaymonopolisethemarket.

• Somearguethatthisuseofsupercomputersisareturntothetimeof

mainframecomputingthatthePCwasareactionagainst.

– Securitycouldprovetobeabigissue:

• Itisstillunclearhowsafeout-sourceddataisandwhenusingthese

servicesownershipofdataisnotalwaysclear.

– Therearealsoissuesrelatingtopolicyandaccess:

• Ifyourdataisstoredabroadwhosepolicydoyouadhereto?

• Whathappensiftheremoteservergoesdown?

• Howwillyouthenaccessfiles?

• Therehavebeencasesofusersbeinglockedoutofaccountsandlosing

accesstodata.


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AdvantagesofCloudComputing

• Lowercomputercosts:

– Youdonotneedahigh-poweredandhigh-pricedcomputer

toruncloudcomputing'sweb-basedapplications.

– Sinceapplicationsruninthecloud,notonthedesktopPC,

yourdesktopPCdoesnotneedtheprocessingpowerorhard

diskspacedemandedbytraditionaldesktopsoftware.

– Whenyouareusingweb-basedapplications,yourPCcanbe

lessexpensive,withasmallerharddisk,lessmemory,more

efficientprocessor...

– Infact,yourPCinthisscenariodoesnotevenneedaCDor

DVDdrive,asnosoftwareprogramshavetobeloadedand

nodocumentfilesneedtobesaved.


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• Improvedperformance:

– Withfewlargeprogramshoggingyourcomputer's

memory,youwillseebetterperformancefromyourPC.

– Computersinacloudcomputingsystembootandrun

fasterbecausetheyhavefewerprogramsandprocesses

loadedintomemory…

• Reducedsoftwarecosts:

– Insteadofpurchasingexpensivesoftwareapplications,you

cangetmostofwhatyouneedforfree-ish!• mostcloudcomputingapplicationstoday,suchastheGoogleDocssuite.

– betterthanpayingforsimilarcommercialsoftware• whichalonemaybejustificationforswitchingtocloudapplications.


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• Instantsoftwareupdates:

– Anotheradvantagetocloudcomputingisthatyouarenolongerfaced

withchoosingbetweenobsoletesoftwareandhighupgradecosts.

– Whentheapplicationisweb-based,updateshappenautomatically

• availablethenexttimeyoulogintothecloud.

– Whenyouaccessaweb-basedapplication,yougetthelatestversion

• withoutneedingtopayforordownloadanupgrade.

• Improveddocumentformatcompatibility.

– Youdonothavetoworryaboutthedocumentsyoucreateonyour

machinebeingcompatiblewithotherusers'applicationsorOSes

– Therearepotentiallynoformatincompatibilitieswheneveryoneis

sharingdocumentsandapplicationsinthecloud.


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• Unlimitedstoragecapacity:

– Cloudcomputingoffersvirtuallylimitlessstorage.

– Yourcomputer'scurrent1Tbyte harddriveissmall

comparedtothehundredsofPbytes availableinthecloud.

• Increaseddatareliability:

– Unlikedesktopcomputing,inwhichifaharddiskcrashes

anddestroyallyourvaluabledata,acomputercrashingin

thecloudshouldnotaffectthestorageofyourdata.

• ifyourpersonalcomputercrashes,allyourdataisstillouttherein

thecloud,stillaccessible

– InaworldwherefewindividualdesktopPCusersbackup

theirdataonaregularbasis,cloudcomputingisadata-

safecomputingplatform!3409/12/17 CMA. TCA Srinivasa Prasad

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• Universaldocumentaccess:

– Thatisnotaproblemwithcloudcomputing,becauseyou

donottakeyourdocumentswithyou.

– Instead,theystayinthecloud,andyoucanaccessthem

wheneveryouhaveacomputerandanInternetconnection

– Documentsareinstantlyavailablefromwhereveryouare

• Latestversionavailability:

– Whenyoueditadocumentathome,thateditedversionis

whatyouseewhenyouaccessthedocumentatwork.

– Thecloudalwayshoststhelatestversionofyourdocuments• aslongasyouareconnected,youarenotindangerofhavinganoutdated

version


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• Easiergroupcollaboration:

– Sharingdocumentsleadsdirectlytobettercollaboration.

– Manyusersdothisasitisanimportantadvantagesofcloud

computing

• multipleuserscancollaborateeasilyondocumentsandprojects

• Deviceindependence.

– Youarenolongertetheredtoasinglecomputerornetwork.

– Changestocomputers,applicationsanddocumentsfollow

youthroughthecloud.

– Movetoaportabledevice,andyourapplicationsand

documentsarestillavailable.


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DisadvantagesofCloudComputing

• RequiresaconstantInternetconnection:

– Cloudcomputingisimpossibleifyoucannotconnecttothe

Internet.

– SinceyouusetheInternettoconnecttobothyour

applicationsanddocuments,ifyoudonothaveanInternet

connectionyoucannotaccessanything,evenyourown

documents.

– AdeadInternetconnectionmeansnoworkandinareas

whereInternetconnectionsarefeworinherently

unreliable,thiscouldbeadeal-breaker.


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• Doesnotworkwellwithlow-speedconnections:

– Similarly,alow-speedInternetconnection,suchasthat

foundwithdial-upservices,makescloudcomputing

painfulatbestandoftenimpossible.

– Web-basedapplicationsrequirealotofbandwidthto

download,asdolargedocuments.

• Featuresmightbelimited:

– Thissituationisboundtochange,buttodaymanyweb-

basedapplicationssimplyarenotasfull-featuredastheir

desktop-basedapplications.

• Forexample,youcandoalotmorewithMicrosoftPowerPoint

thanwithGooglePresentation'sweb-basedoffering


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• Canbeslow:

– Evenwithafastconnection,web-basedapplicationscan

sometimesbeslowerthanaccessingasimilarsoftware

programonyourdesktopPC.

– Everythingabouttheprogram,fromtheinterfacetothe

currentdocument,hastobesentbackandforthfromyour

computertothecomputersinthecloud.

– Ifthecloudservershappentobebackedupatthat

moment,oriftheInternetishavingaslowday,youwould

notgettheinstantaneousaccessyoumightexpectfrom

desktopapplications.


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• Storeddatamightnotbesecure:

– Withcloudcomputing,allyourdataisstoredonthecloud.

• ThequestionsisHowsecureisthecloud?

– Canunauthorisedusersgainaccesstoyourconfidentialdata?

• Storeddatacanbelost:

– Theoretically,datastoredinthecloudissafe,replicated

acrossmultiplemachines.

– Butontheoffchancethatyourdatagoesmissing,youhave

nophysicalorlocalbackup.

• Putsimply,relyingonthecloudputsyouatriskifthecloudletsyou

down.


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• HPCSystems:

– Notclearthatyoucanruncompute-intensiveHPC

applicationsthatuseMPI/OpenMP!

– Schedulingisimportantwiththistypeofapplication

• asyouwantalltheVMtobeco-locatedtominimizecommunication

latency!

• GeneralConcerns:

– EachcloudsystemsusesdifferentprotocolsanddifferentAPIs

• maynotbepossibletorunapplicationsbetweencloudbasedsystems

– AmazonhascreateditsownDBsystem(notSQL92),and

workflowsystem(manypopularworkflowsystemsoutthere)

• soyournormalapplicationswillhavetobeadaptedtoexecuteon

theseplatforms.4109/12/17 CMA. TCA Srinivasa Prasad

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TheFuture

• Manyoftheactivitieslooselygroupedtogetherundercloud

computinghavealreadybeenhappeningandcentralised

computingactivityisnotanewphenomena

• GridComputingwasthelastresearch-ledcentralised

approach

• Howeverthereareconcernsthatthemainstreamadoptionof

cloudcomputingcouldcausemanyproblemsforusers

• Manynewopensourcesystemsappearingthatyoucaninstall

andrunonyourlocalcluster

– shouldbeabletorunavarietyofapplicationsonthesesystems


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CMA. TCA Srinivasa Prasad+91 947 770 [email protected]
