Implementing Virtualization In The Workplace

What You Need To Know About Implementing Virtualization in the Workplace

Shane Cribbs CEO, Georgia Technologies

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T A B L E

O F

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C O N T E N T S

Introduction....................................................1

Introduction

1. Understanding Virtualization......................1

IT departments are making a move to virtualization like never before. Developers have come to learn how much more efficiently they can work in virtual environments, and management is pushing virtualization with cost savings and an improved environmental image in mind. Furthermore, recent trends in IT have caused server and desktop “sprawl”as hardware prices continue to drop. What many fail to realize is that the long-term cost of owning more hardware is many times larger than the initial purchase price. Virtualization alleviates that problem by reducing the number of physical computers in an environment. With several free or very inexpensive options available, even environments with only a single server or workstation are realizing the benefits of virtualization.



1.1 Hypervisors . ......................................2



1.2 Management Interface........................3

2. Realizing the Benefits of Virtualization.......4

2.1 Virtualization on the Desktop.............4



2.2 Virtualization in the Server Room.......4



2.3 E nvironmental, Management and Service Benefits............................5



2.4 Additional Features.............................6



2.5 The Impact on End Users.....................6

3. Selecting a Virtualization Platform..............6 Summary.........................................................7 References......................................................8 About Learning Tree........................................9

For those less concerned with the technical aspects, the fact that virtualization can be a significant part of any “Go Green” initiative creates additional interest. For some or all of these reasons, virtualization has recently become an important option for many organizations.

About The Author............................................9

1. Understanding Virtualization So you’ve heard of virtualization and maybe even heard how much it can help your organization, but what exactly is it and how does it work? While the term “virtualization”can refer to several different technologies and/or implementations, the most common use refers to the employment of virtual machines, which are software implementations of a computer. A single physical computer can run one or more virtual machines, each with its own operating system and set of applications. Each virtual machine is not only isolated from the physical computer, but from other virtual machines as well. To create a virtual machine, an additional level of software is introduced to the physical computer. Technically, this software is referred to as a hypervisor or Virtual Machine Monitor (VMM). This hypervisor is responsible for 1-800-843-8733 • www.learningtree.ca ©2008 Learning Tree International. All Rights Reserved.

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virtualization tasks such as emulating virtual hardware, and passing I/O requests—such as network traffic—from the virtual machine to the physical machine. In essence, a single set of hardware is acting as if it were multiple physical entities from both a user interface perspective and for all network communications. After installing a hypervisor on the physical machine, virtual machines may be created. Virtual machines exist as a group of virtual components, much like a physical computer is composed of physical components. Those virtual components may include devices such as a virtual motherboard, hard disk, video adapter, network adapter and sound card. In addition, some hypervisors support advanced hardware such as USB devices and multiple virtual CPUs. Typically, virtual machines are created from a management tool provided by the vendor where some of these virtual components may be adjusted. For example,

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you may adjust the amount of virtual machine memory, how large the virtual hard disk is and even how many virtual network adapters are installed in the virtual machine. Once the virtual hardware has been created, an operating system is loaded into the virtual machine after which applications and services can be installed and configured.

1.1 Hypervisors Hypervisors come in two general forms, hosted and native. Hosted hypervisors are essentially applications that are loaded on a standard operating system and behave much like any other application. These are useful when you want to maintain a standard operating environment but leverage specific virtualization features. These types of solutions are frequently used for development, testing, training and light server consolidation.

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Diagram A

From the preceding Diagram A, you can see that hosted virtualization introduces some complexity into the computing environment. For example, when a virtual machine needs to write to the hard disk, it must pass that write command to the hypervisor, which passes it to the host operating system, which in turn passes it to the disk to actually be written. In scenarios in which the physical computer will be dedicated to hosting virtual machines, security and stability can be concerns. Most operating systems contain numerous components and features that are useful for workstations or servers, but would not be used on a dedicated hosting machine and could be the cause of potential instabilities and even security vulnerabilities. However, the need to have a fully functional host operating system to perform tasks other than virtualization often outweighs these concerns.

In contrast, native (or “bare-metal”) hypervisors operate without a hosting operating system. In fact, they behave as the operating system while providing virtualization features. Typically, this type of hypervisor is used for servers dedicated to hosting virtual machines.

1.2 Management Interface Most management and administration in a virtual scenario is carried out remotely. However, since local administration may be necessary, especially when troubleshooting network issues, management interfaces are implemented. Vendors usually refer to these interfaces as service consoles or parent partitions. These types of interfaces can range from a full installation of Microsoft Windows to a minimal install of Linux. Since the management interface is essentially a virtual machine that can be controlled by the hypervisor, it has relatively no impact on performance during normal operation.

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Diagram B

You can see in Diagram B above that, without a host OS to impede communications, the hypervisor can more efficiently interact with the physical hardware. In addition to increased efficiency, this allows the hypervisor to manage hardware directly in a manner optimized for virtualization that may not be allowed by a host operating system. Another unique feature of hypervisors that run natively on physical hardware is that they typically do not have any type of interactive user interface. This allows the hypervisors to be written with much fewer lines of code, increasing performance, stability and security.

2. Realizing the Benefits of Virtualization 2.1 Virtualization on the Desktop Virtualization is used on desktop workstations and servers for distinctly different reasons. On a desktop, immediate rewards can be seen by developers and IT staff. Developers can be given additional virtual machines to test applications and installation routines. Leveraging virtual machines eliminates the cost and space required by additional testing computers which, in turn, means more thorough testing as hardware costs decrease. In addition, virtual machines include rollback features, such as snapshots and undoable drives, that allow quick recovery of a previous state, with typical rollback times ranging from less than a second to a couple of minutes.

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IT staff are often responsible for supporting multiple operating systems while only having a single operating system available to them on their desktop. Through the use of virtualization, each member of the IT staff can have multiple operating systems on their computer. This allows them to have different versions of operating systems to more easily walk customers through troubleshooting steps over the phone or via e-mail. They can also use virtual machines for testing and problem re-creation without the danger of corrupting the primary operating system and causing instability or security vulnerabilities.

2.2 Virtualization in the Server Room While taking advantage of virtualization on the desktop is extremely useful, server rooms and data centers are driving many virtualization projects due to their extremely high return on investment (ROI) potential. Virtualizing servers takes advantage of the fact that most physical servers only use about 20% of their capacity. Why are they so underutilized? Because when organizations standardize hardware as a way to reduce management and administrative costs (which it can), they usually end up purchasing hardware that is much more powerful than required for the task at hand. Therein lies the cause of surplus capacity. This raises the question: Why not consolidate many functions onto a single server? Sometimes the answer is simple, such as two applications are not compatible

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with one another and cannot be run on the same server. Other times, flexibility and security are concerns and dictate multiple servers. For example, if authentication, Web server, database and file sharing services were all running on a single machine, a single patch for the database application would mean downtime for all applications as the server is rebooted. But virtual machines can be restarted independently of one another. If each of the previously mentioned services were in their own virtual machine, the database virtual machine could be patched and restarted without affecting the availability of the remaining services. Virtualization can leverage the standardized hardware to run many smaller tasks on one physical machine. Finally, the most obvious advantage of server virtualization is cost savings due to fewer servers. While you may decide to implement more powerful servers, modestly consolidating four existing servers onto one physical server will still provide significant savings. In addition to direct cost reduction, fewer servers provides other benefits, such as reduced server space, and reduced cooling and power costs.

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2.3 Environmental, Management and Service Benefits From an environmental standpoint, virtualization makes a lot of sense as well. First, energy consumption is reduced. Also, in environments where battery backup power is used, fewer batteries are needed. Battery disposal can be very hazardous if not performed properly, especially in the quantities that a larger organization must replace them in a data center. In addition to environmental and cost-saving benefits, virtual machines, by virtue of how they operate, provide significant management and service continuity benefits as well, namely in the areas of virtual machine storage and virtual hardware emulation. Virtual machines are typically stored within a single folder on the physical computer. This enables easy backup and movement of virtual machines. In addition, the hypervisor has a preset list of hardware that it emulates for each virtual machine. This emulated hardware is static and is not dependent upon the hardware in the physical computer, allowing virtual machines to be moved between hosts and remain unaffected by changes in underlying hardware.

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Portability is another advantage of virtual machines that can be leveraged in several scenarios. First, when one host becomes overloaded and another has free resources, virtual machines can be moved to more evenly distribute the load. Second, in the event more total processing power is needed, a new server can be introduced and virtual machines can be migrated to it through a simple folder copy. Finally, for disaster recovery, a simple folder restoration is all that’s required to fully restore all applications, settings and data.

2.4 Additional Features Vendors have also been adding additional features to provide even more advantages to virtualization. The benefits range from simplified backup and hot migrations to centralized management, monitoring and alerting. When combined, these benefits should provide enough motivation for almost any organization to begin a virtualization project or optimize a virtual infrastructure already in place. A current trend, which combines server and desktop virtualization advantages, is to leverage virtualization to provide virtualized desktops for general computing. The idea is to provide relatively inexpensive and lightweight equipment to end users and simply allow them to remotely control centralized virtual machines that have been specially configured for them. While this requires more powerful servers, the desktop machines themselves must only be powerful enough to run the remote control application. A typical implementation may include only a thin client on the users’ desktops which typically requires much less management and administration than a fullfeatured PC. The advantage of this is that all of the virtual desktops can be centrally managed. Therefore, if and when client hardware fails, no data or applications will be lost and no reconfiguration will be needed when replacing it.

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2.5 The Impact on End Users As with any technology, there are pros and cons for the end user. For example, when using virtualization on desktop computers, these virtual machines may tend to be slower than their physical counterparts. The extent of this performance degradation depends on several factors, including the amount of memory in the physical computer, the number of virtual machines being used concurrently and the processing speed of the host server. However, this drawback can be easily addressed with the proper amount of planning and configuration. This holds true for server virtualization as well. When done properly, performance is the same (or better) and all the benefits still apply with no negative impact on end users. Ultimately, virtualization represents several positive results for end users and the organization as a whole. Cost savings from reduced power consumption benefit both the enterprise and the environment, while increased availability and faster disaster recovery plans enable users to be more productive and less frustrated by outages.

3. Selecting a Virtualization Platform When selecting a virtualization platform, the deciding factors typically include price, performance, features and support. In the enterprise market, there are currently three major vendors providing virtualization applications. They are VMware, Xen and Microsoft. VWware is currently leading the virtualization drive with several products aimed at different markets; however, their product offering, for the most part, revolves around their three virtualization applications: Workstation, Server and ESX. Workstation and Server are hosted products which require a supported operating system (Windows or Linux), but have slightly different feature sets to meet the general needs of the virtual machines. ESX is VMware’s flagship native hypervisor product, serving as both the

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operating system and virtualization application. ESX is now marketed as part of the VMware Infrastructure product suite, which includes applications such as the Virtual Center management suite and the VMotion application for moving live virtual machines from one host to another. Xen offers a native hypervisor that competes directly with ESX although it is fundamentally different in that it is an open source project. In early versions, Xen required virtual machines use an operating system that was specially designed to be virtualized. However, recent versions take advantage of virtualization acceleration built into newer processors and support most mainstream operating systems. The focus of the Xen project is to produce a very lean, efficient and secure hypervisor with no real effort put toward add-on products such as advanced management tools. Like many open source applications, Xen encourages third parties to develop applications that will work in conjunction with their hypervisor. Companies such as Virtual Iron and Citrix (previously XenSource) provide solutions based on Xen but add features such as centralized management and high availability. Microsoft is the most recent major player to enter the virtualization market. Microsoft started by purchasing a prewritten virtualization solution from Connectix and rewrote it to bring it in line with Microsoft’s goals and standards. They began with two products, Virtual PC and Virtual Server. Much like VMware’s hosted offerings, they are both hosted products, but each offers features optimized for its intended use. With the release of Windows Server 2008, Microsoft has now entered into the world of native hypervisors with Hyper-V. In addition to the Hyper-V hypervisor, Microsoft also provides a management suite called System Center Virtual Machine Manager which allows centralized management of virtual machines throughout the environment. So the question is…which product is right for your organization? All three vendors offer very compelling

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products with unique advantages. Currently, VMware offers the most mature and robust solution suite. However, the proprietary hypervisor ESX can introduce a steep learning curve along with the most expensive price tag. While the core product of Xen is available for free, the costs begin to mount as you purchase support and management software. And although Microsoft is the newest of the three vendors, it seems to be adding features with substantial stability. Ultimately, all three vendors should be considered and piloted to see how they meet your organization’s needs.

Summary While virtualization promises numerous benefits, it is like any other technology in that it must be fully understood and correctly implemented. Horror stories of virtualization projects gone bad or virtual machines that did not perform well abound. This is simply a matter of improper planning. While there are times when virtualizing a server or application isn’t the best answer, a belief that virtualization is a bad or unsafe technology represents a lack of understanding. Sadly, these misunderstandings all too often cause companies to decide against leveraging this technology, resulting in lost cost savings and wasted time. Although it is not a new technology, virtualization is making a comeback by proving itself as a stable solution to many of the pressures IT environments face today. As this White Paper points out, there are many benefits that can be realized from virtualization, from reducing costs to increasing availability. Management and maintenance can also be significantly improved, thanks to the portability and isolation virtualization provides. As if these didn’t provide enough motivation, virtualization can also help your organization become more environmentally friendly. Properly implemented, virtualization has something to offer almost any organization, being one of the most effective technologies you can implement into your IT infrastructure.

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References Virtual Strategy Magazine http://www.virtual-strategy.com/ There are several blogs but most are not vendor neutral. One that is server-virtualization specific but covers several vendors is: http://servervirtualization.blogs.techtarget.com/ Also see: http://www.cio.com/blog/index/topic/168354 For news, I suggest: http://www.theregister.co.uk/hardware/virtualization/ and http://virtualization.com/

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About Learning Tree International

About the Author

Learning Tree International is a leading global provider of truly effective training to management, business and information technology professionals. Since 1974, over 65,000 public and private organizations have trusted Learning Tree to enhance the professional skills of more than 1.8 million employees. Learning Tree develops, markets and delivers a broad, proprietary library of over 200 instructor-led courses focused on project management, leadership and key business skills, Web development, operating systems, programming languages, databases, computer networks, IT/IS security and object-oriented technology. Courses are presented at Learning Tree Education Centers throughout the world and delivered on site at client facilities. For more information, call 1-800-THE-TREE (1-800-843-8733), or visit our Web site at www.learningtree.ca

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Shane Cribbs CEO, Georgia Technologies [email protected] Shane Cribbs has been working in the IT industry for 13 years with expertise in virtualization, clustering, Active Directory, Windows deployment and Microsoft Office SharePoint Server. Mr. Cribbs is an owner and the CEO of Georgia Technologies, Inc., specializing in integrated solutions of computers, networks and VoIP telephony systems, servicing several markets, including government agencies, private medical practices and public library systems. He is also a Learning Tree Course author , technical editor and instructor.

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