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Slapping cloud management software on top of an existing data centerenvironment isn’t going to cut it. For a true private cloud architecture,you need to brace for major technology, process and personnel change.

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Some thus refer to the cloud layer as a “manager of managers” thatallows data center operators tomove application workloads; reallo-cate memory, storage and other ITresources where the most oomph isneeded; and consolidate data andmanagement in a single “location.” For most data centers, making

this delicate equation work involvessubstantial change of existing infra-structure and practices. You can’tjust slap a layer of cloud manage-ment software on top of your exist-ing servers, storage and networksand call it a private cloud. But formany IT managers, how to retool

existing infrastructure for a privatecloud remains a mystery. In thischapter on building a cloud infra-structure, we explore how to turn anexisting virtualized data center intoa private cloud and how storage,networks and legacy systems willnecessarily change.

AUDITING EXISTING ENVIRONMENTSMost fundamentally, cloud-basedarchitecture changes existingprocesses, so you need to begin byauditing your existing environment.Your existing virtual infrastructure

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S TECHNOLOGISTS struggle to get a handleon the private cloud, they frequentlyarrive at a key realization: Buildinga private cloud often requires anoverhaul of existing data centerinfrastructure. � A private cloud

means a layer of software and management builton top of existing data center infrastructure thatmasks the differences underlying data centerhardware, storage and networks to enable scala-bility, elasticity, and on-demand access to appli-cations and other services.

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may have evolved over time: A serv-er consolidation–focused agenda—rather than a cloud-focused one—may have driven structures andapplication setups. Or you may havebegun with server virtualization torun test and development applica-tions and only later moved to pro-duction server virtual machines(VMs). Obviously, this patchworkapproach to building an infrastruc-ture has an impact on existing ITpractices and policies.So your audit shouldn’t be limited

to the virtualization layer but shouldalso consider the surrounding busi-ness processes that enable a virtualinfrastructure to function. This re-quires taking a hard look at whichaspects of your processes are func-tional and which are dysfunctional.Core areas to consider are storageand networking, but other legacysystems should be evaluated, suchas existing billing and invoicing sys-tems, so that a cloud infrastructurecan encompass chargeback capabil-ities.During your audit of the existing

environment, consider these techni-cal and business process–relatedareas:

� existing VM templates; � the number of physical virtualization hosts;

� the total cluster-free resourcecapacity (e.g., memory, CPU and storage);

� the procedures in deploying

new VMs; � storage allocation and existing process;

� network bandwidth; � VLAN tagging and vSwitchpractices;

� billing systems; and� staff roles.

As you begin your audit, you need to consider physical serversand VMs first.

MAKING VIRTUAL MACHINESCLOUD-READY� VM templates. At the most basiclevel, creating, provisioning andmanaging virtual machines in thecloud differs from existing data cen-ter management practices. In a vir-tual infrastructure, existing changemanagement routines dictate theprocess of creating new VMs, andtheir chief motivation is often toeliminate VM sprawl. Additionally,VM templates—which provide astandardized group of hardware andsoftware settings that are used tocreate new VMs—likely include onlya base OS, service packs and otherpatches. Given their fear of perform-ance problems, most organizationshave steered clear of installing full-blown applications and services intothese templates. In the cloud, however, one goal is

to allow end consumers to createnew applications and services ondemand. When end consumers log

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in to a cloud portal, they expect aservice catalog to offer more than acouple of virtual applications thatcontain merely a base OS build.They want a complete service orapplication. And this self-service ITprovisioning model is likely to runcounter to certain control proce-dures already in place.So you need to confront the

assumptions and procedures of thepast. In the case of templates, thismeans going “up the stack” andinstalling services and applicationsinto VMs. You need to work closelywith the stakeholders who tradition-ally manage these applications andgain approval for VM configuration.And before they can be included in aservice catalog, VMs need consider-able testing and verification.

� A VM-first policy. While the move to a cloud-based model does-n’t exclude physical servers, themore virtualized your existing infra-structure, the easier the transition toa cloud will be. If you haven’t doneso already, adopt a “VM-first poli-cy,” in which new services and appli-cations are virtualized by default.Then, only when it’s been demon-strated that these services cannotperform well virtualized, deploythem on dedicated physical servers. Additionally, it may be time to

reappraise physical servers thatwere originally excluded from theearly phases of virtualization. Thesephysical boxes may have been per-

formance-sensitive servers thatwere considered too tricky to virtu-alize. With the major advances in

hypervisors, it’s time to push thesesystems out of the nest and into thevirtualization layer. Finally, it’s timeto review the policies and changemanagement routines that havebeen enforced on VMs. Are they still valid, or are they a throwback to how things were done in thephysical world? Now that virtualiza-tion has proven its mettle with pro-duction workloads in the data cen-ter, a more aggressive policy isrequired.

MAKING STORAGE CLOUD-READYIn a cloud-based environment, provisioning adequate storage isone of the central pain points, andonly some of the challenges aretechnical. New ways of provisioningstorage for the cloud may be at oddswith storage architecture, or theymay well run afoul of existing datacenter practices and departmentaldivisions. Still, the cloud will changethe data center IT roles and respon-sibilities with which you are familiartoday.

� Architectural differences. Servervirtualization and enterprise-gradestorage technologies have evolvedon diverging paths. Attempts tomarry the two and, thus, gain thebenefits of a cloud environment are

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often a kludge. An enterprise run-ning a decent-sized storage areanetwork (SAN) appliance, for exam-ple, must have direct access to theappliance even to set up a storagepool to boot a single VM. Compare that with a standard

virtualized server, which is a single-image file that runs with virtual diskspace already embedded in it andassumes a user operates on a hostthat is capable of processinginstructions (i.e., CPU) and talkingdirectly to storage devices. The idealhost environment for virtualizationis a massive single server with asmany cores, RAM and direct-attached storage as possible. Butthat’s not how infrastructure withindividual servers and a SAN works.This is not to say that high-level,expensive, safe storage and virtual-ization can’t work together, though.So it’s important for private cloud

architects to take a long hard look at how storage interacts with datacenter architecture. Chances are

that even if your storage pool is bestof breed and virtualized, it was setup to work for day-to-day needs and you don’t manage it much.When you link virtualized resourcestogether into infrastructure-agnos-tic pools with broader access, yourstorage management interface isn’tgoing to “just work” with VMsseamlessly.

� Storage access. In traditional vir-tualization environments, access to storage is strictly controlled, andvirtualization administrators mayengage in weekly or daily battles toget the storage needed. In the worldof the cloud, with a mere click of themouse, end consumers can accessmany gigabytes or terabytes of cost-ly storage with less oversight thanthey had previously. So the chal-lenge is to introduce a cultural and a technology change.The job of the cloud administrator

is to present storage in a way that iseasy to consume yet also reinforcesthe concept that there is no freelunch. As end consumers selectitems from a service catalog, thebest cloud automation softwaremakes them aware of the cost ofstorage through chargebackprocesses. Today, a raft of storage manage-

ment plug-ins for virtualization plat-forms such as VMware’s virtualiza-tion suite, vSphere, allows admins toprovision new storage directly fromVMware’s management console.

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In the cloud, with a mere click of themouse, users can access even terabytesof costly storage withless oversight thanthey had previously.

They save a huge amount of timeand automate processes that, evenwith the help of scripting tools, aretime sinks. Still, while plug-ins are aboon, storage teams may hesitate toallow virtualization administratorsthe rights to use them, as broaden-ing access reduces traditional iron-fisted control over storage arrayconsumption.

� Storage pools. Cloud automationvendors have also discussed creat-ing pools of storage in various“tiers”—gold, silver and bronze cat-egories, for example—with each tierrepresenting differing kinds of disk,RAID levels and number of spindles.But most storage administratorswon’t recognize this model of man-aging storage. Historically, corpo-rate IT has focused more on theapplication—say, an email applica-tion—and quantities of space andIOPS (or I/O per second) needed forusers to access applications. Thebusiness side would often request acertain amount of capacity from thestorage team based on proof-of-concept and scalability tests.

MAKING NETWORKS CLOUD-READYWhile private clouds mask underly-ing differences at the infrastructurelayer to allow for scale and dyna-mism, this homogeneity createsnew network bandwidth and provi-sioning challenges.

� Bandwidth. Even if your networkworks well, with every desk outfittedwith 1 Gigabit Ethernet bandwidthand a handful of solid links to serveeveryone’s needs, you may still havebandwidth problems waiting in thewings. So get ready to invest in toolsfor monitoring network congestion.If you virtualize everything you canand start serving all these resources

from the network—and users haveaccess to do so themselves—thebottlenecks will arise relativelyquickly. If VM sprawl is an issue for your

IT shop, a private cloud will poseeven bigger problems. Your teammay stand up handfuls of serverssimultaneously and create massiveloads that disrupt other operations.Now imagine them doing so fromhome and clogging your entire oper-ation’s Internet connection until youcan corral them. If you’re also plan-ning virtual desktop infrastructureor workspace virtualization, theheadaches are ever-present. To combat these issues, consider

reallocating and expanding band-width to resource-hungry users

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Even if your networkworks well, you maystill have bandwidthproblems waiting inthe wings.

before implementing cloud strate-gies. Many IT shops have a kind of

“fairness doctrine” in place, whereall parts of the organization have anequal share of company networkresources whether they need themor not. But plan on careful segrega-tion of different kinds of users. Justas you create tiers of VM templates,consider tiers of user classes. Andhave headroom in place to accom-modate this allocation of resources. A virtualized environment that

consolidates numerous physicalservers into a smaller number won’tnecessarily add to network traffic,and that hasn’t been a big consider-ation in terms of resource allocation.But revamping your data center intoa private cloud means deliveringmore services over a network tousers who come and go when theyplease. Consider your bandwidthneeds and think hard about anupgrade.

� VLAN tagging. Virtualized net-works also need to be separated toensure data privacy. So they needmechanisms to ensure that thesenetworks can share the same physi-cal network link without compro-mising or leaking informationbetween networks. To allow access to a physical net-

work, most cloud automation soft-ware uses the virtual local area net-work (VLAN) tagging model. Thisapproach requires a network team

to pre-create pools of VLAN IDs ona physical switch. When a new VMor virtual application is created, acloud end consumer eats up theseVLAN IDs without having to ask thenetwork team to set them up.

But VLANs defined on a physicalswitch are not “free.” Most physicalswitches support only a certainnumber of VLAN definitions, andthe name space for VLANs can beconsumed at a much faster ratethan expected. The biggest change here is con-

vincing a network team that creat-ing VLANs up front—which may ormay not be used—is a good idea. In some respects, it flouts a genera-tion of best practices that counselsIT managers to configure only whatis needed to protect resources frombeing hijacked by nefarious intrud-ers.

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Many IT shops have a kind of “fairnessdoctrine” in place,where all parts of the organization havean equal share of network resourceswhether they needthem or not.

(Continued on page 9)

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BUILDING A PRIVATE CLOUD CHECKLISTBUILDING A private cloud requires you to revisit so many existing systems and prac-tices that it can be daunting. But this checklist can help break down what seems likeoverwhelming change into digestible steps. BY BOB PLANKERS

1. Evaluate and Assess� Create a starting point, or baseline,

with an inventory of current hard-ware and software, including exist-ing virtualization, network and stor-age infrastructure.

� Assess existing vendor relationshipsfor virtualization- and cloud-friendlylicensing and support.

� Assess security and businessrequirements.

� Assess vendor roadmaps to avoidlock-in and ensure interoperability.

2. Plan� Start with a specific, well-defined

project, with plans for scaling up andout following success.

� Include ample time in project plansto resolve technical and processissues as they arise.

� Ensure that every aspect of IT is rep-resented, including change and con-figuration management so thatprocess challenges can be addressedup front.

� Ensure that staff members from keytechnical areas—such as network-ing, storage and the data center—participate directly in private clouddesign.

� Document availability, disasterrecovery, and performance needs inthe form of a service-level agree-ment, which will help define success.

3. Deploy� Adopt an attitude that if it needs to

be done more than once, it needs tobe automated.

� Create documented standards andtemplates to ensure consistency.

� Make training available to IT staff.� Communicate and be flexible so that

unanticipated issues can be dealtwith quickly.

4. Manage� Anticipate adjustments as system

requirements become knownthrough experience. Regularly right-size virtual servers to avoid wastedresources.

� Monitor systems and workloads foradherence to service-level agree-ments.

� Institute chargeback mechanisms tofairly and transparently account forresource use.

� Regularly review trends and capacitywith staff from all key technicalareas. �

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Bob Plankers is a virtualization and cloud architect at a major Midwestern university.

� Virtual switches. Virtualizationadmins may also need to re-exam-ine their default settings, which mayoriginally have been created for aserver consolidation project. Mostvirtual switches, for example, have a set number of “ports” into which a VM can be “plugged.” Think of itas a conventional physical devicelike a 48-port switch. Of course, in the virtualization world, you canhave a much greater number of“ports” than in the physical world.Most virtual switches use a staticmodel for assigning ports to VMs.This pool of static ports can quicklybecome depleted, so a virtualizationadministrator has to look closely atvSwitch settings to allow for a moredynamic model or for an approachthat creates and destroys ports onvSwitches as they are needed or discarded.

� IP addresses. Networks have arange of free addresses that candeplete resources at an even fasterrate. These ranges must be largeenough to accommodate the bun-dles of VMs that end consumerscreate. In the U.S. and elsewhere,data centers have moved graduallytoward Dynamic Host ConfigurationProtocol (DHCP) with client reser-vations. In this setup, a VM receivesan IP address from a DHCP serverbut a specified IP address from theIP range associated with the VM’sMAC address. Most cloud automa-

tion software assumes that a busi-ness is comfortable with this movefrom operated, hand-coded, static IP addresses. In truth it is yet anoth-er change in the culture that bothapplication owners and networkteams must overcome.

MAKING BILLING SYSTEMS CLOUD-READY� Chargeback. In most corporateenvironments, IT pitches a budgetbased on an estimate of what it willcost to maintain and upgrade theexisting environment and introducenew technologies. But this old wayof doing things runs counter to thechargeback practices required in acloud, which involves charging backthe cost of IT resource use to indi-vidual departments. Today, only a fraction of organiza-

tions conduct chargeback. It is trickyto accurately price the cost of vari-ous VM configurations. For thoseusing chargeback, the other discon-certing issue is that a VM is not thatmuch cheaper than a physical server,and in some cases it’s more expen-sive. The criteria used to price out aVM does not factor in the substan-tial cost savings of virtualizationthrough freed-up data center spaceas well as reduced power and cool-ing costs.

� Showback. Some organizationsthat have started down the road ofcloud computing have opted for the

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much more user-friendly approachof “showback.” With the showbackmodel, IT departments can demon-strate data on IT consumption tobusiness units. This model encour-ages IT to educate the businessabout the true cost of running vari-ous infrastructure components.

Additionally, chargeback softwarehas focused on counting the amountof memory, disk, network or CPU aVM uses. These chargeback modelsoften fail to include the supportcosts incurred and the value addedby an in-house infrastructure. Theyunderestimate the role of corporateIT in providing a properly auditedand verifiable backup and disasterrecovery strategy, the ability tosecure service-level agreements or,in the event of an outage, ensureturnaround times in terms ofuptime. On a more operational level, most

cloud automation vendors’ charge-back models merely offer variousways to collect data but lack theirown billing and invoicing engines.Instead the data collected has to beparsed through existing third-partybilling and invoice systems. Withouttrue integration among these sys-tems, there can be obvious prob-lems. IT managers should ensurethat integration is manageable froma billing-cycle perspective. Thechargeback and billing system mustalso take into account that even if aVM or vApp is powered off, it stillincurs a charge because of the diskspace it consumes.

MAKING I.T. ROLES CLOUD-READYPriming your data center infrastruc-ture for a cloud environment is onlypart of the battle. Your IT staff maybe entrenched in its views, practicesand relationships. And for a truecloud environment, all of that mustchange. In a private cloud model, your IT

staff has to be willing to share thekeys of the infrastructure kingdomwith other IT departments. IT staffin separate server, storage and net-work silos need to let go of the fief-doms of the past, because the cloudrequires a more holistic approach.Somehow this reorganization has

to take place without underminingthe strong technical abilities of vari-ous members of the teams them-selves. To some degree, the revolu-

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With the showbackmodel, IT departmentscan demonstrate dataon IT consumption,which is part of edu-cating the businessabout the true cost ofrunning infrastructurecomponents.

ADDITIONAL RESOURCES FOR MORE INFORMATION on cloud computing, click on the content titles listed below.

� WHAT CONVERGED INFRASTRUCTURE BRINGS TO PRIVATE CLOUDDesigned with virtualization and cloud computing in mind, next-generation hardware aims to solve the scalability problems of do-it-yourself virtual infra-structures.

� PRIVATE CLOUDS ON THE HORIZONWhether you are trying to move to private cloud today or in research mode forthe future, this report includes all our best tips and guides on how to get there.

� FROM PRIVATE TO HYBRID CLOUD: SIX CONSIDERATIONSIT organizations with private clouds should soon see the value in a hybrid cloudexpansion.

� I.T. SHOPS ROLL THEIR OWN PRIVATE CLOUDSBy building private clouds on-site rather than jumping into public clouds, two IT departments hope to avoid costs and the tricky navigation of the IT health-care sector.

� ENTERPRISES FACE INTEGRATION HURDLES TO PRIVATE CLOUDSThere are serious obstacles between enterprise IT as it exists today and achieving the Infrastructure as a Service vision. �

tion of virtualization has created anew model for the IT professional:someone who is comfortable withall technical areas that make up avirtualization platform. If you havethis kind of IT skill set in-house, cur-rent IT staff can lead the move tothe cloud and bring together variousdepartments and gain trust. Ulti-mately this new IT vanguard isresponsible for shifting the focusfrom defending departmental silosagainst change and toward testing

and validating a service catalog, en-suring that compliance is enforced,and generating an audit trail. If you lack this skill in-house, the

next step is to hire or train existingstaff to break down the technologysilos of hardware, storage and net-works to govern and manage yourprivate cloud model. While ITstaffers may initially buck thechange, they may ultimately ensurethe longevity of their careers ratherthan risk losing their jobs.

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MANAGING CHANGE AND THE END CONSUMERThe success of the private cloudmodel will hinge in part on how ITmanagers respond to the technicalchanges required. Users want todynamically spin up virtual machinesfrom a Web portal, to create customtemplates for VM creation, to viewtheir physical and virtual resourcestogether, and to price out the costsof individual components of a pri-vate cloud infrastructure. If corpo-rate IT doesn’t step up and presentits offering as an external commer-cial provider would, it runs the riskof end consumers taking their busi-ness elsewhere.Ultimately, though, the success

of a private cloud infrastructure willhinge on how you manage change at a human level. Revamping yourinfrastructure for increasing levels of virtualization, standardizationand transparency can work onlywith executive buy-in and IT man-agers on the front lines, ready todeliver on that strategy. �

Mike Laverick is an IT instructor with 17 years of experience in technologies including Novell,Windows and Citrix Systems. Since 2003, he hasbeen involved with the VMware community and isa VMware forum moderator as well as a memberof the London VMware User Group Steering Com-mittee. He is the owner and author of the virtual-ization blog RTFM Education, where he publishesfree guides and utilities for VMware users. He isalso writing a book on building a cloud withVMware vSphere as the foundation.

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