A virtual desktop environment is nothing without virtual desktops.  Poorly performing virtual desktops and applications, or virtual desktops and remote desktop session hosts that aren’t configured properly for the applications that are being deployed, can turn users off to modern end user computing solutions and sink the project.

How you configure your desktop base image can depend on the type of desktop pools that you plan to deploy.  The type of desktop pools that you deploy can depend on the applications and how you intend to deploy them.  This part will cover how to configure a desktop base image for non-persistent desktop pools, and the next part in this series will cover how to set up both linked and instant clone desktop pools.

Before You Begin, Understand Your Applications

Before we begin talking about how to configure the desktop base image and setting up the desktop pools, its very important to understand the applications that you will be deploying to your virtual desktops.  The types of applications and how they can be deployed will determine the types of desktop pools that can be used.

A few factors to keep in mind are:

• Application Delivery – How are the applications going to be delivered to the desktop or RDSH host?
• User Installed Applications – Will users be able to install their own applications?  If so, how are applications managed on the desktop?
• User Profiles – How are the user profiles and settings being managed?  Is there any application data or setting that you want to manage or make portable across platforms?
• Licensing – How are the applications licensed?  Are the licenses locked to the computer in some way, such as by computer name or MAC address?  Is a hardware key required?
• Hardware – Does the application require specific hardware in order to function, or does it have high resource requirements?  This is usually a consideration for high-end CAD or engineering applications that require a 3D card, but it could also apply to applications that need older hardware or access to a serial port.

Application management and delivery has changed significantly since I wrote the Horizon 6.0 series.  When that series was written, VMware had just purchased Cloud Volumes, and it hadn’t been added into the product suite.  Today, App Volumes is available in the Horizon Suite Enterprise SKU, and it provides application layering capabilities in Horizon.  Application layering allows administrators to place applications into virtual disk files that get attached at logon, and this allows you to create a single master golden image that has applications added when the user logs in.  If you don’t have the Horizon Suite Enterprise SKU, there are a few other players in the application layering space such as Liquidware Labs FlexApp and Unidesk, and these tools also provide the ability to abstract your applications from the underlying operating system.

Application layering isn’t the only delivery mechanism.  App Virtualization, using tools like ThinApp, Microsoft AppV, or Turbo, is one option for providing isolated applications.  Reverse layering has all applications installed into the golden template, and applications are exposed on a per-user basis. This is the concept behind tools like FSLogix.  Publishing applications to virtual desktops using XenApp or Horizon Published Applications is an option that places the applications on a centralized server, or you could just install some or all of your applications into the golden image and manage them with tools like Altiris or SCCM.

All of these options are valid ways to deliver applications to virtual desktops, and you need to decide on which methods you will use when designing your desktop golden images and desktop pools.  There may not be a single solution for delivering all of your applications, and you may need to rely on multiple methods to meet the needs of your users.

Supported Desktop Operating Systems

Horizon 7.0 supports desktops running Windows and Linux.  The versions of Windows that are supported for full clone and linked clone desktops are:

• Windows 10 Enterprise (including the Long Term Servicing Branch and Anniversary Update in Horizon 7.0.2)
• Windows 8.1 Enterprise or Professional
• Windows 8 Enterprise or Professional
• Windows 7 SP1 Enterprise or Professional
• Windows Server 2008 R2 (RDSH and Server-based Desktop)
• Windows Server 2012 R2 (RDSH and Server-based Desktop)

In order to run desktops on Windows Server-based OSes, you need to enable the “Enable Windows Server desktops” setting under View Configuration –> Global Settings and install the Desktop Experience feature after installing the OS.  There are some benefits to using Windows Server for your desktop OS including avoiding the Microsoft VDA tax on desktop VDI.  The choice to use a server OS vs. a desktop OS must be weighed carefully, however, as this can impact management and application compatibility.

Instant clone desktops are supported on the following operating systems:

• Windows 10 Enterprise
• Windows 7 SP1 Enterprise or Professional

The Horizon Linux agent is supported on the following 64-bit versions:

• Ubuntu 14.04 (note: VMware recommends disabling Compviz due to performance issues)
• Ubuntu 12.04
• RHEL and CentOS 6.6
• RHEL and CentOS 7.2
• NeoKylin 6 Update 1
• SLES 11 SP3/SP4
• SLES 12 SP1

The Linux component supports both full clone and linked clone desktops in Horizon 7.0.1.  However, there are a number of additional requirements for Linux desktops, so I would recommend reading the Setting Up Horizon 7 Version 7.0.1 for Linux Desktops guide.

For this part, we’re going to assume that we’re building a template running a desktop version of Windows.  This will be more of a high-level overview of creating a desktop template for Horizon, and I won’t be doing a step-by-step walkthrough of any of the steps for this section.  Once the desktop image is set up, I’ll cover some of the ways to optimize the desktop templates.

Configure the VM

Building a desktop VM isn’t much different than building a server VM.  The basic process is create the VM, configure the hardware, install the operating system, and then install your applications.  Although there are a few additional steps, building a desktop VM doesn’t deviate from this.

You should base the number of vCPUs and the amount of RAM assigned to your virtual desktops on the requirements for of the applications that you plan to run and fine tune based on user performance and resource utilization.   Horizon doesn’t allow you to set the CPU and RAM allocation when deploying desktop pools, so these need to be set on the template itself.

The recommended hardware for a virtual desktop is:

• SCSI Controller – LSI SAS
• Hard Disk – At least 40GB Thin Provisioned
• NIC – VMXNET3
• Remove Floppy Drive, and disable parallel and serial ports in BIOS
• Remove the CD-ROM drive if you do not have an alternative method for installing Windows.

Note: You cannot remove the CD-ROM drive until after Windows has been installed if you are installing from an ISO.

BIOS screen for disabling Serial and Parallel ports and floppy controller

You’ll notice that I didn’t put minimums for vCPUs and RAM.  Sizing these really depends on the requirements of your user’s applications.  I’ve had Windows 7 64-bit desktops deployed with as little as 1GB of RAM for general office workers up to 4GB of RAM for users running the Adobe Suite.  Generally speaking, customers are deploying knowledge or task worker desktops with at least 2 vCPUs and between 2-4 GB of RAM, however the actual sizing depends on your applications.

Install Windows

After you have created a VM and configured the VM’s settings, you need to install Windows.  Again, it’s not much different than installing Windows Server into a VM or installing a fresh copy of Windows onto physical hardware.  You can install Windows using the ISO of the disk or by using the Microsoft Deployment Toolkit and PXE boot to push down an image that you’ve already created.

When installing Windows for your desktop template, you’ll want to make sure that the default 100 MB system partition is not created.  This partition is used by Windows to store the files used for Bitlocker.  Since Bitlocker is not supported on virtual machines by either Microsoft or VMware, there is no reason to create this partition.  This will require bypassing the installer and manually partitioning the boot drive.  The steps for doing this when installing from the DVD/ISO are:

1. Boot the computer to the installer
2. Press Shift-F10 to bring up the command prompt
3. Type DiskPart
4. Type Select Disk 0
5. Type Create Partition Primary
6. Type Exit twice.

Once you’ve set up the partition, you can install Windows normally.  If you’re using something like the Microsoft Deployment Toolkit, you will need to configure your answer file to set up the proper hard drive partition configuration.

Install VMware Tools and Join the Template to a Domain

After you have installed Windows, you will need to install the VMware tools package.  The tools package is required to install the View Agent.  VMware Tools also includes the VMXNET3 driver, and your template will not have network access until this is installed.   The typical installation is generally all that you will need unless you’re using Guest Introspection as part of  NSX or your antivirus solution.

After you have installed VMware Tools and rebooted the template, you should join it to your Active Directory domain.  The template doesn’t need to be joined to a domain, but it makes it easier to manage and install software from network shares.  I’ve also heard that there are some best practices around removing the computer from the domain before deploying desktop pools.  This is an optional task, and it’s not required.  I’ve never removed the machines from the domain before provisioning, and I haven’t experienced any issues.

Install The Horizon Agent

After you have installed the VMware tools package and joined your computer to the domain, you will need to install the VMware Horizon Agent.  There are a number of new features in the Horizon 7 Agent install, and not all features are enabled by default.  Be careful when enabling or disabling features as this can have security implications.

One thing to note about the Horizon 7 agent is that there is a Composer component and an Instant Clones component.  These items cannot be installed together.  A desktop template can only be used for Linked Clones or Instant Clones.

Installing Applications on the Template

After you install the Horizon Agent, you can begin to install the applications that your users will need when they log into Horizon View.

With tools like Thinapp available to virtualize Windows applications or layering software like FlexApp, Unidesk and App Volumes, it is not necessary to install all of your applications in your template or to create templates for all of the different application combinations.  You can create a base template with your common applications that all users receive and then either virtualize or layer your other applications so they can be delivered on demand.

“Finalizing” the Image

Once you have the applications installed, it is time to finalize the image to prepare it for Horizon.  This step involves disabling unneeded services and making configuration settings changes to ensure a good user experience.   This may also involve running antivirus or other malware scans to ensure that only new or changed files are scanned after the image is deployed (Symantec…I’m looking at you for this one).

VMware has released a white paper that covers how to optimize a Windows-based virtual desktop or RDSH server.  Previous versions of this white paper have focused on making changes using a PowerShell or batch script.   VMware has also released a fling, the OS Optimization Tool, with a graphical interface that can simplify the optimization process.  Whenever possible, I recommend using the fling to optimize virtual desktop templates.  It not only provides an easy way to select which settings to apply, but it contains templates for different operating systems.  It also provides a way to log which changes are made and to roll back unwanted changes.

Prior to optimizing your desktops, I recommend taking a snapshot of the virtual machine.  This provides a quick way to roll back to a clean slate.  I recommend applying most of the defaults, but I also recommend reading through each change to understand what changes are being made.  I do not recommend disabling the Windows Firewall at all, and I don’t recommend disabling Windows Update as this can be controlled by Group Policy.

Before you shut the virtual machine down to snapshot it, verify that any services required for applications are enabled.  This includes the Windows Firewall service which is required for the Horizon Agent to function properly.

Shutdown and Snapshot

After you have your applications installed, you need to shut down your desktop template and take a snapshot of it.  If you are using linked clones, the linked clone replica will be based on the snapshot you select.

That’s a quick rundown of setting up a desktop template to be used with Horizon desktops.

In the next part of this series, I’ll cover how to create desktop pools.