virtual desktop infrastructure

Virtual Desktop Infrastructure

Is It Right For You?

Author Damian Davis / Gary Jensen

Date 05 November 2008

Document Reference 99999-EXT

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Customer: Virtual Desktop Infrastructure

Title: Is It Right For You?

Reference: 99999-EXT

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Copyright © Silversands Limited 2008. Not to be disclosed to any third party without the express written permission of Silversands Limited

Copyr ight In format ion This document is provided for informational purposes only and Silversands makes no warranties, either express or implied, in this document. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Silversands. © 2008 Silversands Ltd. All rights reserved. All trademarks are property of their respective owners.




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Executive Summary Virtual desktop infrastructure, or VDI, is more of a concept than a single product. Essentially, it is the delivery of desktop capability to a user where the desktop is hosted in the data centre and the user simply ‘remote controls’ the desktop. From a user’s point of view, this is very similar to working with a Citrix Metaframe or Presentation Server desktop but there are some key differences in a VDI solution. Where Citrix delivers a desktop (or individual applications) to users from a shared platform, VDI delivers each user a dedicated and independent full operating system (Windows XP or Vista, for example). This removes some of the historical issues with Citrix where application compatibility is a concern and performance or reliability issues can impact all the users. In its most basic form, a VDI solution simply requires a host platform (such as Microsoft Hyper-V or VMware ESX) on which the virtual desktop can be configured. However, this is not flexible and does not provide a manageable or scalable solution. The key to unlocking the dynamic capability of VDI is a brokering solution, which acts as a gateway between the users and the virtual host. This solution makes virtual desktops available on demand, shuts them down when users have logged out and generally manages the availability, delivery, connectivity and capabilities of the VDI solution. In some cases, this basic approach can be enough to deliver a capable virtual desktop infrastructure. However, there can be other manageability and functionality issues that require consideration. These include the amount of storage that the virtual desktops take up, how roaming profiles will be managed, how application customisation will be handled and how hundreds or thousands of virtual desktops will be managed from an update, patching & configuration change point of view. Although VDI has been available for a few years, it is only in the last 12-18 months that it has become a serious option for desktop delivery because it is only in this timeframe that some of the original products have matured or that new products have been created to deliver the enhanced functionality that is required to make this a truly dynamic and capable desktop delivery option. There are now many products from vendors such as Microsoft, VMware, Citrix, Quest, Provision Networks and others and it can be the case that the best solution is a combination of different products from different vendors. Unfortunately, it is not necessarily easy to decide which is the most appropriate and there are many factors that need to be taken into account including business requirements, existing technologies, licensing arrangements, organisational configuration, scale and so on. With over 20 years of desktop deployment experience, and relationships with the key virtual infrastructure vendors, Silversands is ideally placed to advise and assist with virtual infrastructure projects for organisations with hundreds or thousands of desktops.




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In troduct ion

Background

You may be aware of the emerging technology platform known as ‘virtual desktop infrastructure’ or VDI. This is a generic concept defining the delivery of hosted desktop infrastructure to users from a centralised infrastructure platform. A recent survey by research services group IDG identified desktop virtualisation as a prominent growth market with estimates of 34 percent of corporate desktop delivery being virtualised by 2010. Given the expected growth in VDI implementations it is likely that the marketplace for supporting technologies will mature. As a result it is likely that VDI solutions will become more integrated solutions with better feature sets. In recent years, the concept of VDI has grown in the IT consciousness as a potential ‘silver bullet’ solution that will simplify the continuous cycle of desktop hardware replacement and OS upgrades, and reduce future outlay. Some elements of this statement are true, given the correct environment and management. However, an incorrectly designed or configured VDI solution can be as difficult to manage as traditional deployments.

Document Purpose

This whitepaper is intended to provide an overview of a VDI solution from an architectural, management and administration perspective. It is intended that the reader is informed on the existing capabilities and limitations of VDI deployments and can assess the suitability of the technology for their particular requirements.




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What i s S i l versands? With over 20 years’ experience, Silversands understands the intricate nature of delivering complex solutions for commercial and non-commercial organisations and has a verifiable track record in successful project completions. We are committed to the quality delivery of quality solutions. We have a deep understanding of the specific technical, management, performance & political issues our clients are confronted with. Our working style is collaborative and designed to enable far-reaching and sustainable change. Silversands has in-depth experience of the design and implementation of Microsoft solutions, having been involved with its solutions from launch. Our latest projects have included migration, implementation and support for organisations such as B&Q (3,000 users), BUPA (19,000 users), Southampton City Council (4,500 users) and Plan (6,000 users). Our team of Microsoft specialists is backed by qualified PRINCE2 project management, infrastructure and development skills enabling us to provide complete solutions and genuine business benefit. Silversands is a Microsoft Gold Certified Partner for:

Advanced Infrastructure Solutions

Information Worker Solutions

Security Solutions

Custom Development Solutions

Unified Communications Solutions. These major accreditations can only be gained by having a high number of MCSE, MCITP and MCSD-qualified consultants and by implementing customer-validated solutions using multiple Microsoft technologies for large organisations across multiple industry sectors. These solutions include Windows 2003 / 2008, Active Directory, Exchange 2003 /2007, Operations Manager, Configuration Manager, Office Communications Server, SharePoint Products & Technologies and ISA Server, as well as software developments in SQL Server, .NET, Office, Access and other areas. Silversands is one of only a relatively small number of such accredited partners worldwide. Additional news and information about Silversands solutions, products and other accreditations can be found on our website at www.silversands.co.uk. As a result of our long standing relationship with Microsoft we have access to the people who can provide detailed technical input towards the solution architecture and design, if required. In conclusion, our extensive knowledge of the Microsoft solution suite, and our close relationship with Microsoft, places us in an ideal position to work with you, to deliver innovative solutions based on industry standard technologies.

http://www.silversands.co.uk/




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What I s VDI ? Prior to looking at VDI, it is worth considering the traditional methods of desktop delivery. Principally, these are standard PCs running an operating system such as Windows, or server-based computing (SBC); perhaps better known as thin-client, solutions such as Windows Terminal Services or Citrix Presentation Server/XenApp.

A desktop or laptop device for each user has been the platform of choice for over 20 years and this has made it the most widely used architecture in place today. The user is guaranteed a quality of service from their PC, can work offline and gets access to the full operating system, which they have the potential to customise extensively (although, of course, this tends to be controlled in many environments). Server-based computing, on the other hand, offers an alternative whereby the application processing is centrally managed in the data centre and clients connect using remote control technology running on either a standard PC or a thin terminal. With consolidation ratios in the region of 50 users/desktops per thin-client server, there can be significant advantages in terms of desktop management costs, flexibility and business continuity. For example, users’ desktop sessions can be load balanced across many servers and, essentially, can be controlled & managed from a central location. Additionally the SBC infrastructure can be leveraged to provide remote access to line of business applications for mobile/home workers and which can support business continuity in the event of a disaster situation. Managing a distributed environment with potentially thousands of client devices, however, is not a trivial task financially, operationally or from a security perspective and this is where the flexibility and dynamic capability of a server-based computing environment can deliver a number of advantages. This is particularly true where standard PCs are replaced with thin terminals but the operational benefits are less clear when PCs are maintained at the desktop for whatever reason. Where thin terminals are utilised, the typical 3 or 4 year PC replacement cycle (including all the attendant build & migration aspects) is almost entirely negated because the performance requirements of the thin terminals never change because all the processing is completed at the server end. Naturally, thin-client computing is not a panacea to all IT desktop issues and there are number of considerations to take into account. Careful resource management is necessary to ensure that resource over commitment does not occur. If a poorly written application utilises available server resources then potentially a large group of users are affected. Application compatibility needs to be carefully tested and controlled. All users are sharing sessions on the same server and, therefore, if multiple versions of the same application are required then installation and configuration complications arise (it is not unknown for standalone thin servers to be installed for one rogue application). Furthermore interruption of service affecting a thin server will impact all users connected to the server. This impact is not limited to a single user as in the local desktop model. So, where does VDI fit into the picture? Essentially, desktop virtualisation decouples the desktop session from the local device and centralises the OS on virtual infrastructure delivered from a central location. Connectivity to the virtual desktop is provided using thin client protocols over the LAN and WAN infrastructure.




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1. Client terminal

requests desktop

session

2. Broker assigns

session to user

3. Desktop session is

delivered from virtual

infrastructure

4. Desktop is

displayed on user’s

terminal

Figure 1: Basic virtual desktop infrastructure

In theory, this delivers the management and support advantages of centralised computing but without the issues of undesirable application interaction, customisation constraints and other factors. Users benefit from the flexibility offered in having a dedicated personal computer, running a native desktop operating system, such as Windows XP, Vista or Linux. From a management perspective, the desktop PC is now in the data centre and can be centrally administered. Each desktop is individually controllable from a resource allocation perspective, and can be flexibly located across virtual infrastructure. Arguably, the virtual desktop is simpler to deploy and securer than a similar server-based computing desktop, as each desktop is individual and, therefore, does not need as much configuration to restrict the impact of multiple users accessing the same resources. Furthermore, if a virtual desktop crashes then it does not affect the other VDI users, whereas a problem on a thin-client server potentially affects all users. However, it is not quite as simple as just implementing a virtualisation platform and then deploying desktops to users, although this is entirely possible. For instance, each user would need to be directed to one specific desktop and this leads to a number of potential issues such as needing to have, say, 100 desktops ‘powered up’ even though there might only be a small number of users actually in the office, on the basis that you wouldn’t be able to tell which virtual desktop each user would need to attach to.




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Equally, with a typical desktop PC requiring somewhere in the region of 10-15Gb of disk space at a minimum, implementing hundreds or thousands of these as virtual desktops would require a serious amount of centralised storage. From a user point of view, and noting that a 1:1 relationship between user and virtual desktop is not ideal, roaming profiles need to be implemented and these can be difficult to manage, as well as slowing down logon and logoff. Similarly, although the desktop images are now centralised on virtual infrastructure, they still need to be managed as individual systems. An infrastructure with 1000 virtual PCs will, in theory, need the same type of effort in terms of application deployment, patch management, antivirus and other administration that would normally be applied to a physical PC. So, the true VDI picture is now starting to emerge. The basic solution, a virtual desktop hosted on a server, needs to be supplemented by a number of other technologies and solutions to make the environment truly manageable, dynamic and optimised. To enable this truly manageable environment, Silversands has modelled the administrative impact of virtual desktop deployment in comparison to traditional desktops and has built a portfolio of the best of breed products that can deliver this capability in a layered way. That is, as each layer is added to the solution, the capabilities are increased and the management issues are decreased. However, as always, the payoff is that the ‘per desktop’ cost of VDI increases accordingly. Consequently, careful consultation is required to ensure that the solution implemented meets the business requirements and available budgets.




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Si lversands ’ s V ir tua l Desktop Offer ing

Introduction

Silversands has found that a basic virtual desktop solution may support small number of users effectively but, as the user count increases, so do the administrative overheads. A successful 50 user pilot may become extremely difficult to scale to 500 users, for instance, without the introduction of complementary technologies. Of course, costs are always a key factor in considering any new technology deployment and Silversands recognises this. To this end, Silversands recommends a modular approach to VDI, with building block technologies that can be added to the solution in stages. Some of the components are pre-requisite for a VDI solution and then others can be added as budget allows or as requirements evolve.

BROKERING PROVISIONING

STAGE 2

APPLICATION

STREAMING

STAGE 3

ENVIRONMENT

MANAGEMENT

STAGE 4

BASE VIRTUALISATION

FOUNDATION

Virtual

Infrastructure

REQUIRED OPTIONAL

Figure 2: VDI solution stages

Foundation - Base Virtualisation and Brokering Solution

At the very core of a VDI solution is the virtual infrastructure that provides the platform for the virtual desktops. There are a number of options that can provide this including Microsoft Hyper-V, VMware ESX and Citrix XenServer. Of course, if you already have these in your infrastructure then you already have the basis for a VDI solution.

Silversands actively implements and supports solutions hosted on either the Microsoft or VMware platforms and there would be a number of reasons for implementing one or the other. Both technologies are enterprise class and utilise hypervisor technology to provide the best performance and the choice of which is the most suitable solution will come down to factors including scale, availability requirements, licence optimisation, general preference and so on. The brokering solution manages the connections between the users and the virtual desktops and is the other absolutely essential part of the virtual desktop infrastructure. A broker solutions needs to deliver a number of capabilities to be considered effective. These include:

Desktop pooling and affinity to either allow users to connect to any available desktop or to connect to a specific desktop.

Management of desktop availability, including the ability to power up and down desktops based on numbers of users coming on line or logging out.

Authentication pass-through to prevent double logins, which can frustrate users.

Session maintenance so broken connections are automatically reconnected to the same desktop.




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Silversands recommends Citrix XenDesktop or VMware Virtual Desktop Manager to deliver this component of the service. In a similar way to the choice between VMware ESX and Microsoft Hyper-V for the virtual infrastructure deployment, the choice between XenDesktop and Virtual Desktop Manager will come down to requirements, cost, licence availability and preference.

Stage 2 – Provisioning Management

In the stage 1 VDI deployment detailed above, each guest desktop runs its own separate virtual hard disk, delivered from the SAN or storage infrastructure. For a hundred desktops this could be 1 to 1.5TB of storage. With a thousand desktops the figure would be 10 to 15TB. Furthermore, in this configuration, each virtual desktop image would require individual management and maintenance – Windows updates, application updates, configuration changes and so on. Provisioning management delivers a mechanism to stream the virtual desktop hard disk from an image server and share this amongst many desktops. The benefits of this approach are clear! Since there is potentially just one Windows XP/Vista image with a hundred or thousand connections to it, that means hundred or thousand times less storage used and only one image to manage, update and patch. The solution that Silversands recommends for provisioning management is Citrix Provisioning Server for Desktops.

Stage 3 – Application Streaming

To add a further dynamic capability to the virtual desktop, application virtualisation or streaming technology can be used to distribute user-specific applications to the desktop image on demand. Products delivering this capability include Microsoft Application Virtualisation (formerly SoftGrid), VMware ThinApp and Citrix XenApp Application Streaming. Application virtualisation has many benefits over traditional installations because the application runs in a ‘sandbox’ client (similar to a web application running in a browser):

The application can be assigned to and removed from a user by instantaneous policy change.

It can follow a user wherever they login.

Multiple versions of the same application can run at the same time on the same desktop.

Updates can be delivered as an instant update for an existing package, or as a new package, which allows both old and new versions to run during a migration period.

Application virtualisation complements the desktop provisioning technology of stage 2 by enabling total separation of the operating systems from the applications that run on it and, therefore, providing a level of dynamic capability that cannot be matched by traditional desktop deployments. The selection of the application virtualisation solution for any organisation requires consideration based on factors such as the vendors of the other layers, optimised licensing, manageability and features.




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Stage 4 – Environment and Profile Management

Although the previous VDI stages deliver a capable and effective solution, there can still be some manageability issues related to profiles and application customisation. Whilst it is true that these can be managed using native tools, configuration & scripts, it can leave an environment that is difficult to manage, support and scale. Consequently, the final element in the total VDI solution is an environment and profile manager. Products capable

of providing this include AppSense Environment Manager and RTO Profile Manager. The functions that these products provide include:

Automated profile management to generate the user profile look and feel and to control the experience using rules set in central policies.

Streamed profiles to enable efficient and reliable delivery of the user’s desktop, as they need it. Profile streaming improves the average login time of a user substantially.

Application feature lockdown to restrict features of a desktop down to the level of individual buttons within application, if required. As a result, the security and reliability of the desktop is greatly enhanced.

Self healing of user profiles to resolve typical corruption issues automatically, ensuring support overheads are minimised.

These features provide mechanisms to control the user experience and additionally maximise the use of the base virtual infrastructure by providing a level of control over the desktop processes.

As for many components of a total VDI solution, there are many factors that define the requirement for this type of functionality and the most appropriate product to provide it.




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Conclus ions There is no doubt that, similarly to a server virtualisation programme, a virtual desktop infrastructure solution can provide many benefits and potential costs savings to an organisation. However, as this whitepaper demonstrates, it is not necessarily as simple as implementing a desktop on a virtual platform and delivering this to users. There are a number of key solution areas that make up a total VDI solution and each of these areas has a number of potential solutions from different vendors. At the very least, a brokering solution is required to provide a gateway service between the users and the available desktops. Furthermore, in many situations it will be necessary to add additional layers to the solution to provide a more manageable, capable and dynamic infrastructure, which can be scaled to many hundreds or thousands of users. Dependent on selected technologies and vendors, the benefits of this type of infrastructure are many and varied:

Virtual desktops can be built and configured at a moment’s notice and be ready within a few minutes.

A new and pristine desktop is delivered to the user every time the log on.

Unlike thin client, users continue to receive an independent and dedicated operating systems instance.

There are no application interaction issues to worry about.

A crash in one desktop will not affect any other user.

Application virtualisation can enable very quick and easy deployment and update of applications in a fraction of the time taken for legacy methods.

Business continuity is enhanced because the desktop images can be copied to a DR site and/or users can run their office desktop from any remote location, such as home.

Power utilisation can be reduced. With over 20 years of desktop deployment and management experience, and critical partnerships with key VDI vendors such as Microsoft, VMware and Citrix, Silversands is ideally placed to help you and your organisation make sense of your requirements and to determine which of these solutions are the most appropriate to implement for maximum benefit.




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Appendix – Sample 500 Desktop ROI Analys is

VMware VDI 500 desktop Sample

This sample ROI/TCO statement is specifically costed for a basic VDI (VMware VDM) solution without additional options. It is intended as a guide to the potential costs and returns of a VDI solution.

These figures have been generated by the VMware ROI/TCO online calculator application

virtual desktop infrastructure

Technology

desktop virtualisation

delivery of desktop

concept of vdi

virtual host

vdi solutions

presentation server

vdi implementations

thousands of virtual