System Image Utility lets you prepare an installation image that starts the computer then installs the system. You can also choose to not install software and have client computers start up (or boot) from an image stored on the server. (In some cases, clients don’t even need their own hard disk.)
Using NetBoot and NetInstall, your client computers can start from a standardized OS X configuration suited to specific tasks. Because the client computers start from the same image, you can quickly update the operating system for users by updating a single boot image.
NetBoot requires a boot image. NetInstall requires an installation image.
A boot image (.dmg file) is a file that looks and acts like a mountable disk or volume. NetBoot images contain the system software needed to act as a startup disk for client computers over the network.
An installation image (.nbi folder) is an image that starts up the client computer long enough to install software from the image. The client can then start up from its own hard disk.
Boot images and installation images are disk images. The main difference is that a .dmg file is a proper disk image and a .nbi folder is a bootable network volume (which contains a .dmg disk image file). Disk images are files that behave like disk volumes.
You can set up multiple NetBoot or NetInstall images to suit the needs of groups of clients or you can provide copies of the same image on multiple NetBoot servers to distribute the client startup load. You can also use a NetRestore image to quickly restore a volume.
NetBoot service can be used with NetBoot and NetInstall images along with OS X client management services to provide a personalized work environment for each user.
Apps for setting up and managing images
You use the following OS X Server apps to set up and manage NetBoot, NetInstall, and NetRestore:
System Image Utility, to create OS X NetBoot, NetInstall, and NetRestore disk images. This utility is installed with OS X in the /System/Library/CoreServices/ folder.
PackageMaker, to create package files you use to add software to disk images.
Property List Editor, to edit property lists such as NBImageInfo.plist.
To create an image, you must have valid OS X image sources or volumes. You cannot create an image of the startup disk you’re running on.