Specifications

184 Chapter 11 Working with NetBoot Service and System Images
Imaging Multiple Clients Using Multicast asr
You can enable a multicast image server using the Mac OS X Server Multicast asr
command. Multicast asr can restore multiple clients simultaneously from one looping
multicast of an asr disk image.
Each client can receive the restore image at any time during a multicast of the image,
and the client continues receiving the first part of the next multicast until the client
receives the complete restore image.
The server multicasts only one copy of the restore image at a time, and all clients
receive this copy.
If the server finishes multicasting the restore image and a client is still requesting the
image, the server multicasts the image again. Thus, using multicast asr to stream
images to multiple clients doesn’t congest the network nearly as much as Network
Install with multiple clients.
To enable the image server, use the asr tool with the -server flag and a correctly built
image and plist.
To start a multicast server for a specified image:
$ asr -source <compressedimage> -server <configuration.plist>
The image does not start multicasting on the network until a client attempts to start a
restore. The server continues to multicast the image until the process is terminated.
To configure a client to receive a multicast stream:
$ sudo asr -source asr://<hostname> -target <targetvol> -erase
The client receives the multicast stream from <hostname> and saves it to a client.
To overwrite an existing image, add -erase. Using -erase with -target indicates an
existing image should be overwritten when doing a multicast.
Choosing a Boot Device Using systemsetup
To choose your boot device, use the systemsetup tool. When setting the startup disk,
you must know the full path to core services. For example,
to boot from “Disk 2,” which is now mounted in /Volumes, you would enter:
$ sudo systemsetup -setstartupdisk /Volumes/Disk\ 2/System/Library/
CoreServices