Creating a Virtual Desktop

The actual VDI environment setup begins by installing a New Desktop Virtual Machine in the Virtual Machines tab.

The desired number of CPU cores, the memory allocated, and the name all need to be specified in the dialog for creating the VM (Figure 4). You need to include the VirtIO driver in the setup when installing Windows systems from scratch; this ensures that the use of VirtIO hardware is possible right from the outset. An existing PC system can be converted using third-party software like Acronis (e.g., True Image) or Red Hat's V2V tool. No additional drivers are needed for Linux desktops.

Figure 4: Setting up a new virtual machine.

Once the virtual machine has been installed and tested with all of the required software components, you can then start preparing your future template for automatic deployment of virtual machines. You need to run the Sysprep tool for Windows. On a Windows 7 guest system, you open the registry editor regedit and search for the following key:

HKEY_LOCAL_MACHINE\SYSTEM\SETUP

Create a new string here and run sysprep:

Value name: UnattendFile
Value data: a:\sysprep.inf
START/RUN: C:\Windows\System32\sysprep\sysprep.exe

Select the Enter System Out-of-Box Experience (OOBE) item below System Cleanup Action in the Sysprep tool. You also need to enable Generalize option to change the SID. Select Shutdown as the value under Shutdown Options . Complete the process by pressing OK – the virtual machine shuts down automatically. You also need to configure the Volume License Product Key via the shell on the RHEV Manager:

# rhevm-config --set ProductKeyWindow7=product-key --cver=general

Other Windows systems (like XP) require different configurations, which can be found in the RHEV documentation.

A Linux guest system can also be prepared for automatic deployment:

# touch /.unconfigured
# rm -rf /etc/ssh/ssh_host_*
Set HOSTNAME=localhost.localdomain in /etc/sysconfig/network
# rm -rf /etc/udev/rules.d/70-*
# poweroff

To generate a template, select the appropriate item in the context menu of the desired VM. A quick check of the Templates tab reveals that the template has been created successfully and now stores all of the virtual machine settings.

Next, press New in the Pools tab to create a desktop pool for the desired VDI application. A pool is responsible for providing an arbitrary number of desktop VMs on the basis of a template. The name, the number of allocated VMs, the template to be used, the memory size and the number of required CPU cores, as well as the operating system, can be selected in the dialog (Figure 5).

Figure 5: Creating a pool in the VDI environment.

Once the pool has been created, you can move on to configure user access. To do this, use the Permissions tab in the pool settings. You can either assign user rights to a single user or to groups from the directory service. The UserRole gives VDI users sufficient permissions.

Another variant on VDI desktop deployment is to provide one or more dedicated virtual machines (either desktops or servers) for a particular user or for whole user groups. Roles are then assigned in the virtual machine's permissions. With this basic system, users could now work with the VDI environment.

The User Portal

A user's access to virtual desktops is via the user portal:

# https://rhevm.lab.ovido.at/UserPortal/

If you use a standard PC as a client device, you need to install virt-viewer as the SPICE agent on Windows from the SPICE website [2]. On a Linux client, you need the SPICE browser plugin for the Firefox browser.

A thin client is the easiest way to provide user access [4]. To test functionality, use a free trial (e.g., IGEL [5]). For a test with RHEV, I recommend either the IGEL UD3 or UD5 Dual-Core, Linux Advanced thin clients.

To log on to the user portal, use your account details from the directory system. Single sign-on also is an option on an IGEL thin client.

Figure 6 shows the user portal with several virtual desktops available. You can open these virtual workstations by double-clicking on the system.

Figure 6: The RHEV environment user portal.

The user portal also offers even more advanced features.

If the administrator has granted VDI users advanced user rights, they can reconfigure these virtual machines or provision virtual machines for themselves or other people with a template. Thanks to this feature, it is possible, for example, to provide internal software developers with the necessary resources for testing and development.

Conclusions

Creating a VDI solution with RHEV provides a solid platform for image-based desktop virtualization that goes beyond the beaten track of app center functionality or application virtualization.

Proprietary solutions available on the market today undoubtedly offer a more feature-rich environment. However, when requirements and applications do not change on a daily basis, RHEV is a good and very cheap alternative.

It is important to remember the application options in the context of paravirtualization, where RHEV offers interesting features. Any Linux-supported hardware can be the basis for RHEV or oVirt.