100% network (remote) install -- No direct machine access?

[S. W. Davison]

I'm a kickstart beginner, but it seems to me that this ought
to be possible.  Maybe someone can point me at the right
documentation...

We have many sites which are geographically distant from
each other.  At each site there are 10-20 machines running
an old version of Linux.

We would like to upgrade all the machines to RHEL 3, but we
would like to make the upgrades entirely remotely controlled
and entirely automated.  Specifically, we don't want to be
in the situation where personnel at each site must visit
each machine for any purpose.  We are trying to avoid:
o  Any use of floppies or CDs.
o  Any use of console output from the machines.  (Many of
    them do not have consoles, unless you plug one in
    especially.)
o  Any keyboard activity on the machine.  (Many of them do
    not have keyboards attached in their normal service
    configuration.)
o  Any need to go into the machine's BIOS setup to enable
    network booting or PXE.  (As far as I know, you can do
    that only with a local keyboard and console.)

Reading the kickstart documentation, it looks as if one way
to accomplish a kickstart install is to put a kickstart file
(ks.cfg) on an ext2 partition of the machine to be upgraded.
The ks.cfg file would specify an NFS host where the
installation tree was available.  Then you boot from a
boot/install floppy, and at the boot prompt you enter:
     linux ks=hd:sda3:/mydir/ks.cfg

OK.  If I can do that, it seems to me that it ought to be
possible to build the necessary vmlinuz, intitrd, and
whatever else I needed (the stuff that would ordinarily
be on the boot/install floppy), put them into /boot on the
machine to be upgraded, and then change lilo's default boot
command to:  "linux ks=hd:sda3:/mydir/ks.cfg"

Then, if I do a "shutdown -r" over a network connection, the
target system should reboot and go straight into the
kickstart installation, just as if it had booted from the
floppy disk.

Is that possible?  Can anyone point me at documentation for
setting up the necessary boot files?

Thanks for your patience in reading this, and many thanks
for any suggestions.

Stowe Davison
s.davison at computer.org