Live ISO over http

[robinsmidsrod]

Most likely you don't have enough memory on the machines to run everything in memory, so iSCSI or NFS is usually the way to go. You'd also need that for any kind of data persistence. You say workstations, so I'm assuming you'd like to be able to store something on these machines that actually survive a reboot. If so, you'll need somewhere to store it.

But your core problem is that when the Linux kernel has started up the memdisk memory is no longer available (only the Debian initrd is at that point available to the kernel). You'll therefore need to provide a network location for the rest of the files the livecd needs. Debian (and Ubuntu) uses a live system called casper, and you can find an example of how to boot it in my extensive menu linked from http://ipxe.org/examples. You can also find some general information about network booting at http://networkboot.org/ which you might find useful.