Deploying System Images

Deploying system images is, relative to creating them, quick and easy. This, of course, is the point of system deployment; your goal is to deploy this system image as quickly as possible to your computers.

The Apple Software Restore (ASR) system built into Mac OS X suits this goal nicely by providing a highly optimized system restoration mechanism. The term “restore” is used here to mean the process by which you copy the contents of a system disk image to a bootable system volume. Thus, the ASR system is technically a volume duplication mechanism that can be used to make bit-for-bit clones of entire volumes in a matter of minutes.

In this section you will learn how to use the ASR system to restore system images to local volumes. The source for those system images can be either another local volume or shared on the network. Note that this section focuses specifically on system restore techniques, which will be demonstrated as if you were restoring to a single volume. Scaling out these techniques to all your computers simply means repeating the restoration workflow over and over again for each computer. This type of automation is easily handled using a script or a remote management tool such as Apple Remote Desktop 3.

Also note that, as with any system restoration mechanism, the ASR restoration process requires an actively booted system to run it. In other words, you cannot restore an operating system to a local volume without first booting the computer from another operating system that has already been deployed. Further, using the ASR system you cannot restore an operating system on top of the operating system your computer is currently using. Because most Macs have only a single local volume, this presents a “chicken before the egg” type of situation, the solution to which is the main focus of Chapter 5, “Using NetBoot for Deployment.”