Many organizations are on the verge of revamping their existing workstation concept or even replacing them altogether. Windows 7 is therefore a logical realization for many organizations. With the most recent virtualization solutions, the ‘classic’ use of Windows 7 on rich clients is, according to Ruben, not a matter of course; it can also be done in a different way. Desktop virtualization has developed into a serious, attractive and effective desktop delivery platform. In this article, Ruben Spruijt outlines the five different desktop virtualization concepts, the role of Windows 7 and Microsoft App-V within these concepts and the MED-V and XPM solutions for Windows 7.
Application and desktop delivery
If there is a trendy word in the IT industry, then, as well as Cloud Computing, this has to be ‘virtualization’. Virtualization is nothing more than the decoupling detachment of IT resources. The forms of virtualization that are most frequently applied include network, storage, hardware/server, desktop and application virtualization. The virtualization of desktops can be subdivided into five different concepts. The objective of these concepts is to provide the user with a ‘desktop’ upon which web-architected and windows applications can be executed. Desktop Virtualization is a significant component in the entire range of solutions concerning making ranges of applications available to end-users. Application and desktop delivery is a process which has the goal of offering applications independent of location and workstation, so that the user can work onsite, online, offsite and offline anywhere and at any time.
When studying and determining which solution best suits the users and your organization, it is essential that you ask yourself two questions:
- What is the execution platform for the applications?
Within the execution platform, system resources such as the CPU, memory, disc and network are used in order to execute the Windows and web-architected applications. The most frequently used implementation platforms include the following: Desktop, Laptop, Mobile Internet device, Virtual Desktop Infrastructure and Remote Desktop Services. The choice of implementation platform is the most fundamental decision made! The applications are executed locally on the device or centrally in a computing centre. Every implementing platform has its own characteristics. In practice, every organization actually possesses a mixture of workstation access scenarios. The theories: “Less is more” and “Cut out the exceptions” should always be borne in mind!
- In what way are applications made available on the execution platform?
An execution platform is great, especially with Windows 7, but if there are no applications available on this platform, this platform is of no real value to the end-user. The second question is this: How do the applications (which are critical for the company) get onto the implementation platform?! A number of solutions exist for making Windows applications available on the implementation platform. The forms that are most frequently used include installation or virtualization. With installation, applications are automatically installed on the workstation and, where possible, installed in an unattended manner, within the scope of which the implementation platform, the workstation, is adapted. The installation of the application in a base image is also one of the possibilities available. When applications are made available by means of virtualization, these are available ‘on demand’ on the implementation platform. No adjustments are made to the execution platform within the scope of this.
Application Virtualization is an essential and indispensable component for all desktop delivery solutions and server-hosted VDI in particular. The description of the functional value, the impact on the infrastructure and the specific properties of the various Application Virtualization solutions is an interesting subject for a new article.
Desktop virtualization x5
Making applications available to the end-user, separately from the technology used, is the ultimate strategic aim of an ICT infrastructure! The Virtual Desktop (vDesktop) is an essential component in the range of Application and Desktop delivery solutions and in essence, provides the following functions:
- Flexibility: Detach the vDesktop from the endpoint
- Flexibility: Several vDesktops next to one another
- Access: vDesktop works independently of location, endpoint and network
- Access: Uniform workstation
- Security: Server Hosted – VDI; data in the computing centre
- Freedom: Every user has their own desktop
- Management: Hardware-independent ‘image’
- Legacy: It is simple to offer legacy applications on a state-of-the-art platform
- Sustainability: Power Management, handling the necessary resources in an efficient manner.
Desktop Virtualization is the separation of the desktop, the operating system and the applications from the underlying endpoint. This form of virtualization can be subdivided into two types: With the first type of virtualization, the end-user applications are executed remotely, server hosted, and presented at the endpoint via a Remote Display Protocol. With the second type of Desktop Virtualization solution, the applications are executed at the endpoint, client-side, and presented locally on this workstation. If we study the two virtualization concepts in more detail, five different types of Desktop Virtualization can be defined, these include:
- Client-side (executed locally) bare-metal client hypervisor
- Client-side (executed locally) client-hosted hypervisor
- Server-hosted (executed remotely) shared desktop
- Server-hosted (executed remotely) personal virtual desktop
- Server-hosted (executed remotely) personal physical desktop
A graphic overview of the five different desktop virtualization solutions can be found in Figure 1.
Figure 1; Overview of the Desktop Virtualization solutions
Overview of the Desktop Virtualization solutions
The five different Desktop Virtualization solutions and the role of Windows 7 are outlined in the following paragraphs.
Remote Display Protocol
The Remote Display Protocol in Windows 7 and Server2008R2 plays an essential role for the server-hosted desktop virtualization solutions. RDP 7 supplies the end-user with the following: Aero support, DirectX remoting, Multi-monitor support, Multimedia Redirection and bi-directional audio. In practice, the end-users’ experience is positive, especially in a LAN scenario. Optimization for 2D/3D, Flash and Silverlight applications is not yet available.
Server hosted shared remote desktops, RDS
Desktop Virtualization, by means of ‘Server hosted shared remote desktops’, is a solution for gaining remote access to desktops and applications that are executed on a Remote Desktop Server (RDS) in the data centre. Access to the desktop or application is not connected to a location or end-user equipment and the execution of the programme takes place centrally on the server. The information appears on the client's screen via a remote display protocol such as Microsoft RDP or Citrix ICA/HDX. Every user has his/her own desktop session but shares the computer platform with other users. Other frequently used terms for this type of desktop virtualization include the following: Terminal Services, Remote Desktop Servers (RDS) and Session or Presentation Virtualization. Suppliers of ‘Server hosted shared remote desktops’ solutions include, for example, Microsoft, Citrix (XenApp) and Quest (vWorkspace).
Microsoft Windows 7 is a ‘single user’ client operating system; however a multi-user operating system is required for this type of desktop virtualization. Therefore no role has been set aside here for Windows 7. However, the Remote Display Protocol of Windows Server2008R2 is comparable with that of Windows 7. It is, for example, possible to use Windows Media Player, SilverLight, Flash and DirectX with the Microsoft RDP7 protocol and experiences with this have been positive (especially in a LAN environment).
Server Hosted Personal Remote Virtual Desktops, VDI
Server hosted Personal Remote Virtual Desktops is a solution for gaining remote access to Windows 7 or legacy Windows XP desktops that are executed on a virtual machine in the datacentre. The Virtual Infrastructure does not operate using hardware and ensures availability and manageability. Other frequently used terms for this type of desktop virtualization include the following: Virtual Desktop Infrastructure (VDI) or Server Hosted Virtual Desktops (SH-VDI). The use of Server hosted VDI does not require the Windows XP/7 vDesktop to be connected to a location or item of end-user equipment. Each user has his/her own unique, personal and completely isolated workstation. Programme execution, data processing and data storage take place centrally on the personal desktop. The information is displayed on the client’s screen via a remote display protocol such as Microsoft RDP, Citrix ICA/HDX or VMware ‘PC-over-IP’, to name but a few. Suppliers of overall solutions for ‘Server Hosted Personal Virtual Remote Desktops’, for example, include Microsoft (RDS-V), VMware (View), Citrix (XenDesktop) and Quest (vWorkspace).
The importance of Microsoft Windows 7 with this type of desktop virtualization is to supply a Remote Display Protocol (RDP7) and a state-of-the-art client operating system.
Stateless and Statefulll Desktops
Stateless and Statefull are essential terms, especially in relation to server-hosted remote personal desktops. It is important to understand what these two terms mean.
Stateless Desktops: In practice, a number of different terms are used for stateless desktops; pooled, none-persistent or standard desktops are frequently-used terms. The essence is the same, the virtualized desktop is and will always remain clean and ‘pristine’; therefore ‘stateless'. All machine-related modifications, for example applications that are installed by a user, are removed when the user logs off. User-specific settings that are recorded in the user profile, however, can be stored and re-used. In addition to the aforementioned benefits of Desktop Virtualization, stateless desktops also offer the following specific properties:
- The simple roll-out and update of basic images
- A virtual desktop is guaranteed to be 100% identical
- The user always has the same (clean) workstation
- Less effort is required by the management team due to the standardization of images.
Stateful Desktops: In practice, a number of different terms are used for Stateful desktops, including assigned, persistent or private desktops; terms that are frequently used. The essence is the same, the user is and will always remain connected to a vDesktop on a 1:1 basis. When the user has the freedom to install software, the machine-related adjustments continue to be maintained within this desktop, which is where the term ‘Stateful’ is derived from. In addition to the aforementioned benefits of Desktop Virtualization, a Stateful desktop therefore has a specific property, namely:
- Freedom to install software within the desktop, for example.
An important point of special interest with regard to Stateful desktops is the fact that the roll-out phase, update, upgrade and security of the operating system and the applications is less simple to manage than with the stateless desktops. The impact on (central) storage is also greater than with stateless desktops. So, which is better, stateless or Stateful?! The answer to this question depends on the functionality that the end-users require and the impact of this functionality on the ICT department.
Server Hosted Personal Remote Physical Desktops
An optimum experience has not yet been gained by the end-user with Remote Desktop Services and Server Hosted VDI when using graphic intensive 2D/3D, Next Gen and Unified Communications applications. A significant reason for this is the fact that the presence of graphic processor power is lacking in the virtual desktop. The server hosted personal remote physical desktop is the solution and offers users remote access to Windows 7 or legacy Windows XP desktops. These desktops are executed on a physical machine in the data centre. Costly blade (professional) workstations or PCs are frequently used for the physical machines. (Figure 2 is an example of a HP blade workstation solution).
Figure 2, blade workstation solution
The GPU in each blade ensures that every vDesktop is equipped with sufficient graphic processing power in order to be able to execute multimedia, 2D/3D, NextGen and Unified Communications applications. Monitor information is presented on the endpoint device via an optimized remote display protocol. In order to be able to present the information with the end-user gaining the best possible experience with this, additional requirements may be made with regard to bandwidth, latency or locally available (software) components. The expectation is that graphic performance in the physical desktop will become available in the Virtual Machines to some extent over time. Microsoft RDP in Windows7 can only make extremely limited use of the physically available GPU at present. The ‘Server Hosted Personal Remote Physical Desktops’ solution is supplied by HP, Citrix and Teradici, to name but a few.
Client-side Virtual Desktops, CS-VDI
Client-side desktop virtualization is a solution through which the Virtual Machine(s) is/are executed locally at the end point. The Hypervisor ensures that every virtual machine operates independently of hardware and renders it possible to utilize several Virtual Machines on the workstation at the same time. The hypervisor plays an essential role and can be subdivided into two categories, the ‘bare-metal’ category and a ‘client-hosted’ hypervisor.
The bare-metal client hypervisor is often referred to as Type#1, as this can be used directly from the hardware resources. The result of this is a ‘near-native’ performance.
The client-hosted hypervisor is installed as an application on the Windows, Apple or Linux operating system, and provides a broader level of hardware support. As this hypervisor is installed on the operating system, this is referred to as ‘Type #2’. The performance of the vDesktop is acceptable for the average user, but is definitely not maximal.
Citrix XenClient, VMware Client Virtualization Platform, Neocleus and Virtual Computer are bare-metal solutions. Microsoft VirtualPC, XPM, MED-V, VMware ACE- and Fusion, Parallels Desktop, Sun VirtualBox are client-hosted desktop virtualization solutions. The role of Windows 7 within client-side virtual desktops is primarily to provide a state-of-the-art client operating system. The Remote Display protocol is not applicable for the local execution of applications on the vDesktop.
XPM and MED-V
The ‘Windows XP mode for Win7’ (XPM) is a client-hosted ‘Type#2’ desktop virtualization application. This desktop virtualization function is already present in the Professional, Enterprise and Ultimate versions of Windows 7. Nevertheless, the objective of XPM is to make legacy applications that do not function (well) available on a Windows 7 workstation. The legacy applications are executed in the virtual machine and presented (under water via RDP) on the Windows 7 workstation.
XPM uses Microsoft VirtualPC, through which a number of specific integration functions are added. In order to be able to make use of XPM, the hardware from the endpoint must support the hardware-assisted virtualization method AMD-V, Intel-VT or VIA-VT in the CPU.
Microsoft Enterprise Desktop Virtualization (MED-V) is a desktop virtualization solution which many people are unfamiliar with. The function of MED-V can be compared in part with XPM, where XPM does not have any central management functions and MED-V excels in these. XP mode for Windows 7 is primarily of interest for single-users and small environments, whilst MED-V provides business and enterprise circles with the correct management functions. As is the case with the application of Microsoft application virtualization (App-V) on desktops or laptops, MED-V is a component of the Microsoft Desktop Optimization Pack (MDOP). Software Assurance is required for this purpose.
Desktop Virtualization; Good, Bad and Ugly?!
Despite a large number of benefits of desktop virtualization, a number of challenges should also be mentioned here. Providing answers to the questions below will provide assistance when studying the reality and feasibility of the various desktop virtualization solutions:
- Is the virtualization concept and the solution proven? What is my definition of proven?!
- What impact will there be on (central and local) storage? VDI + Storage = Deep Impact!
- What is the end-user’s experience, what can one expect and will I be satisfied with this?
- Will we make use of a stateless server-hosted VDI solution?
- Teaser: A stateless Server Hosted VDI solution can be compared with a Remote Desktop Server (TS) to a level of 90% in terms of its functions.
- What does the application of desktop virtualization mean for my ICT organisation; do we have the correct skills and mindset?
- How can I use offline desktop virtualization? Will I need to apply desktop virtualisation for this?
- Do my end-users require total freedom on the workstation and, if so, why?
- Do I have intensive resource and graphic applications? How do I go about offering these?
- Do I possess the correct Microsoft (VECD) licences for my virtual desktops?
- Who from the ICT management team is responsible for the virtual workstation?
- What is the migration strategy?
Desktop virtualization offers a large number of functions, both for the end-users and for the ICT organization. A study into the functionality, impact, feasibility and the effect on TCO, is and will remain an essential component. It is possible to write a completely new article regarding the Good, the Bad and the Ugly of desktop virtualization. The Bad and Ugly are of particular interest :-) and would make an interesting subject for a further article.
Application Virtualisation enables Windows applications to be made available at a workplace without making changes to the operating system. Neither do you have to install the application at the workstation. In other words, even if the application is not locally installed you can simply run the application, save data with it and print. The local client does not have to be adapted.
Microsoft Application Virtualization (App-V) enables fast application delivery in a client-side and server-hosted environment whereby mutual application conflicts are excluded. This considerably reduces the throughput times of application packaging and delivery compared to the traditional deployment methods. There are various reasons for using Application Virtualization. The primary reasons for using Application Virtualization are:
- Applications are no longer installed on the client-side or server-hosted machines;
- No more conflicts between applications;
- Eliminates the need for regression testing;
- Multiple versions of applications can be used simultaneously;
- Consolidation of Remote Desktop Services;
- Fast application roll-out and upgrades;
- Stabilises Windows profiles;
- Creates a dynamic application delivery infrastructure which allows applications to be used online, offline, on-site, off-site, locally and centrally;
- Empowers dynamic application delivery in a stateless server-hosted VDI and server-hosted Remote Desktop Services environment;
- Makes image management easier; less core applications in base image.
There are two kinds of Microsoft App-V licenses, one for Remote Desktop Services and one for Desktop operating systems like Windows 7. Microsoft Desktop Optimization Pack (MDOP) which includes a total of six Desktop Optimization solution contains Microsoft App-V.
Application Virtualization and VDI
Server Hosted Virtual Desktops (VDI) is a fascinating concept of delivering desktops and applications to users. The pros and cons of this solution are already explained. While VDI provides important advantages, all resources come together in the datacenter. That means that the CPU resources, memory resources, networking and disk resources all need to be facilitated from a single point--the virtual infrastructure. The impact on capacity and I/O of storage in a Server Hosted Virtual Desktop scenario is big. Understanding how storage design has a big impact on your VDI os available: http://www.brianmadden.com/blogs/rubenspruijt/archive/2009/12/10/vdi-and-storage-deep-impact.aspx
Application Virtualization is an important component when designing and implementing VDI. Microsoft App-V version 4.6 now supports a shared cache functionality. This means that App-V Client is able to treat the package cache as a readonly file. This capability was added to support multiple App-V client machines or VMs access to a single package cache and saves on the storage capacity costs. A full description of the configuration can be found here: http://blogs.technet.com/virtualworld/archive/2010/01/20/getting-started-with-the-app-v-shared-cache-in-4-6-rc-part-1.aspx
Desktop virtualisation has developed into a serious, interesting and effective desktop delivery platform. Microsoft has a clear vision in the field of application and desktop delivery and fulfils a vital role in this with Windows7 and Server 2008R2. Many organizations are on the brink of replacing their existing workstations and a choice must be made between ‘traditional’ deployment or desktop virtualization. The point in time at which this moment will arise is different for everybody, but one thing is for certain and that is that this moment shall come! Users expect a higher level of flexibility, freedom and functionality from the workstation, whilst the IT organization places cost-reduction, manageability and compliancy high on its agenda. By using Windows 7, Application Virtualization and Desktop Virtualization, functions that were not previously possible (or were not very good) are now within reach. This article has outlined the various desktop virtualization solutions, the role of Windows 7 and the Power of Application Virtualization. The objective here was to provide a clear picture of the opportunities (and impossibilities) offered by desktop virtualization. “Power to the People, Windows 7 rocks!”
About the author
Ruben Spruijt works as a Technology Officer at PQR, a leading organization in the design, implementation and migration of advanced ICT infrastructures. In his role, Ruben primarily focuses on Virtualization and Application and Desktop Delivery. Ruben has given presentations at a number of conferences both within this country and overseas and has also published a number of different articles on this matter. These can be downloaded from www.virtuall.nl.