System Center Configuration Manager 2007 : Operating System Deployment - Boot Images

• PXE during a network boot

• Removable media such as a CD or DVD-ROM

• A direct copy from a DP

The next sections discuss these delivery methods.

PXE Booting

PXE booting is typically used for bare-metal or new hardware installations when the system does not have a ConfigMgr client agent installed. Using PXE booting requires meeting the following list of criteria:

• A DHCP server must be available for use.

• The network must allow the PXE broadcast packets to reach the PXE server. PXE and DHCP use BOOTP (Bootstrap Protocol), which is a broadcast based protocol. Layer 3 network devices do not pass broadcast traffic by default; the PXE server must be on the same network segment as the client attempting to PXE boot, or you must configure the Layer 3 network devices to forward the broadcasts to the PXE server.

  Most organizations already have BOOTP broadcasts forwarded on their Layer 3 devices to support DHCP; configuring them to forward BOOTP broadcasts to support PXE is a nearly identical process with the only difference being a different destination server.

• You must install the boot images on the PXE distribution point. This is a commonly forgotten and misunderstood step. When you add a PXE service point to your hierarchy, ConfigMgr takes over the installation of WDS on the PXE service point system. When installed, the PXE service point then registers an additional PXE-based distribution point, listed along with the other DPs in the hierarchy.

Removable Media

Typically, you use removable media for bare-metal installation of new hardware where PXE booting is not feasible. This includes the following situations:

• Over a WAN because the network will not forward the PXE broadcasts.

• Unavailable because the target system does not support it. (It has been a long time since network cards did not support network boot using PXE, but it is possible.)

• When you want to be absolutely certain that a system does not connect to the network prior to being fully loaded and fully patched to a designated baseline.

• The target system is in a protected subnet such as a DMZ (demilitarized zone, also referred to as a perimeter network) and cannot communicate back to the site system.

You can create images for removable media by right-clicking a task sequence and choosing Create Task Sequence Media. This launches the straightforward Task Sequence Media Wizard, allowing you to choose which type of media to create. You can burn the resulting image to a CD or DVD or place it on a bootable USB device.

You can create three types of task sequence media:

• Stand-alone— Creates a self-contained image that contains Windows PE and all the packages and information specific to a task sequence—except for software updates. Using stand-alone media allows you to run a task sequence on a target system without connectivity to a ConfigMgr site system.

  When you create a stand-alone image, the system prompts for a distribution point from which to copy packages. You can set task sequence variables specific to this media image, allowing you to customize the task sequence while knowing that it will not connect to the site server during installation.

  The system also prompts you to choose a media size during the creation of the image: 650MB (CD), 4.6GB (DVD), or 8.5GB (DL-DVD). Depending on the size of packages included in the task sequence, there may be multiple images created; choosing the CD image size of 650MB guarantees multiple images. When you boot a system to stand-alone media, it acts as if the task sequence used to create the media was advertised to the system with a mandatory advertisement.

• Bootable— Creates a burnable image of the chosen boot image. This allows the target system to boot into Windows PE as if you delivered the Windows PE image using PXE. You can also initiate the task sequence in a bootable media image from within Windows using the autorun feature of the image. This allows the bootable image to behave as if delivered using a ConfigMgr software distribution.

  A new ConfigMgr R2 option in the Task Sequence Media Wizard relevant to bootable media is to enable unknown computer support. This enables the new unknown computer support functionality of R2.

• Capture— Creates a CD that allows you to capture a reference system outside of a task sequence; the image is not bootable, and you must initiate it from within an installed operating system using the Autoplay function.

  The capture media option launches a wizard that copies Windows PE to a hidden, bootable, file-based partition. It syspreps the system and then reboots into Windows PE where it captures an image of the system. Note that the proper sysprep files must already exist on the target system. The wizard also prompts for a target location, filename, and credentials. Figure 1 shows the first screen of the Image Capture Wizard.

Figure 1. The Image Capture Wizard in action

The capture media can be useful in a variety of circumstances, such as if you already have a perfect reference system or a perfect process for creating the reference system. Another use of the capture media would be to import an image from a competitive imaging system; you would first deploy the image to a suitable reference system and then recapture it into a WIM format using the image capture media.

Using a Distribution Point

The final method of delivering Windows PE is through ConfigMgr itself! If a system already has a ConfigMgr client agent installed and an OSD task sequence is advertised to the client and initiated, ConfigMgr downloads the boot image containing Windows PE to a special pseudo-partition on the hard drive. This pseudo-partition is then set to be the active partition. An automatic reboot is initiated, and the system is booted into the Windows PE image contained in the active pseudo-partition.

Incorporating Windows PE

Each of the methods just described in the previous sections causes the target system to boot into a boot image containing Windows PE. When in Windows PE, an advertised task sequence is initiated or continued. The primary reason for using Windows PE is to perform those tasks on the system you cannot perform while the host operating system runs, such as deploying or capturing an image. Windows PE is a robust environment that supports most things available in Windows Vista, including advanced techniques and tools such as scripting and plug-and-play driver detection.

Network access is critical to the success of the task sequence in Windows PE (except for the stand-alone media option). For Windows PE to connect to the network, it must have the proper network drivers installed. OSD uses Windows PE 2.0 (ConfigMgr 2007 RTM) or Windows PE 2.1 (ConfigMgr 2007 Service Pack 1); both versions are based on Windows Vista and use Windows Vista drivers. Integrating new drivers into the boot images is straightforward, and you can accomplish this in several different ways:

• The Import Driver Wizard includes a page allowing you to add drivers to selected boot images.
  
  
• You can right-click an already imported driver and choose Add to Boot Image from the context menu.
  
  
• The properties of each boot image include a Windows PE page, which contains a list box for drivers. You can click the starburst button at the top to add drivers, as shown in Figure 2.
  
  

  Figure 2. Adding a driver to a boot image

  

  
  This last method is difficult to use because it only lists simple driver names and not versions or other identifying information.