Benefits of Using Windows Deployment Services

The fact that WDS is available for free as part of Windows Server 2008 is a huge benefit. Although it may not be the most feature-rich of all the different OS deployment solutions on the market, it's a good solution for quickly deploying Windows Server and Workstation operating systems with a great deal of automation at no additional cost. WDS offers the following benefits:

• Can be used to deploy Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008 to bare-metal computers
• Designed and built on top of the core Windows setup technologies (Windows PE, WIM, and image-based setup)
• Can be used to reprovision workstations and servers with a previous operating system to Windows Vista and Windows Server 2008
• Offers improved management capabilities: WDS can be managed both from an MMC snap-in and through the command line with WDSUTIL.EXE
• Integrates with Active Directory
• Scalable Windows PE environment supports plug-ins using an open API for standards-based support
• Can transmit data and images via multicast

Scenarios for Windows Deployment Services

If you don't already have a system "imaging" or operating system deployment solution in place, WDS can drastically reduce the time it takes to deploy Windows-based operating systems in your environment. In addition, when used in conjunction with effective user group policies, WDS can reduce the amount of maintenance required. Since WDS is initiated by booting the computer into a PXE and then loading it over the network, even a regular user could fairly easily be walked through reloading the operating system if it had somehow been corrupted. This assumes that you have restricted access to your workstations so that they don't have any local files to begin with. In the server space, you could have a datacenter operator simply "rack and stack" a group of servers, start them up, and initiate a server image load without the operator needing to know any intricate details about what options to select during setup. Simply put, WDS is a good option for rapidly deploying Windows operating systems throughout an environment.

WDS is part of what Microsoft likes to call a "zero-touch deployment strategy." Loading the OS is one thing, but loading applications is a completely different story. This is why WDS is only part of the greater puzzle of Windows deployment. WDS can be used not only to load the base operating system, but when used in conjunction with distribution shares, it can also be used to load additional third-party drivers, patches, and even applications at the time of the install. This layered approach makes it easy to mix and match base images with various driver sets and applications to tailor your images with your needs.

Even if you have to load applications manually either on your workstations or your servers after the OS is installed, automating the bare installation can still save you significant time and resources-which, of course, equates to saving money. For the purpose of WDS, you will need to learn how to install and configure WDS and set up your clients PXE boot, create images, and create unattended setup files. This is significant up-front engineering work, but in an organization with hundreds of servers, it is well worth the effort.

The general procedure for WDS is to install the server, configure the server, add your images, deploy the images, and lastly, maintain your images. This last task can be a nightmare: Typically, an image is made for a particular system build with all the appropriate base applications and utilities preloaded. This is then marked as the baseline image. The problem is that as changes are made in the environment-such as application setting changes and system updates-you will eventually need to go back and update your baseline image to create a new one. Updating the baseline image typically means dumping the current baseline image, then making all the necessary updates, running sysprep to reseal it, and finally recapturing this new baseline image. Without this level of maintenance, you run the risk several months later of loading images on your network that are not appropriately patched or are incorrectly configured. Unfortunately, this is time-consuming and in most cases error-prone. The new WIM format helps out considerably in this area since WIM images can be mounted onto the file system like regular drives and then manipulated, so you can copy down new drivers, language packs, or hotfixes and easily reseal it.

Components

WDS comprises a number of components that interact to get the job done. For starters, the WDS Server itself hosts the core PXE server and manages communications between client and server. A TFTP Server is used to dish out images to PXE clients. Significant enhancements have been made to the TFTP Server that allow for faster communications by controlling the communication windows. Finally, a file share called REMINST points to the folder on the server where the WDS images are kept. This is used by the WDS client when uploading Install images created from Capture images.

WDS Installation

Installing WDS requires that a bit of infrastructure be in place before it will function correctly. The basic requirements for installing WDS are shown in Table-1 (next section).