Re: [Etherboot-developers] Booting over Fast Ethernet

[Anselm M. H. <eth...@ho...>]

Hello Miguel A. Mota Jr,

Saturday, October 05, 2002, 9:55:35 PM, you wrote:
> [...]
> a Beowulf Cluster.  The Nodes boot a custom CD-based mini-Linux distribution
> and configure themselves via DHCP, thus making them quite inexpensive and
> plug-n-play.  I feel that this mixture of technologies makes cheap and yet
> efficient clusters.
> My understanding is that they booting their kernels from a Server.  I was
> wondering if it could be possible to have our Nodes boot an ISO image off
> our Server in a similar fashion?

Not quite, if you don't want to spend a fortune on RAM. The problem
with booting an CD-ISO-Image is that you have to transmit it first and
then place it somewhere inside your computers' memory. Transmitting it
would be vanilla standard configuration probably, but the point is the
high RAM usage. I recommend you going the usual way: Copy the
Root-Filesystem from that CD-ROM onto a hard disk on a "boot server"
(might be the same machine as your main server, but not neccessarily),
give it an entry to /etc/exports (nfsserver needed), and let the
machines boot with root-over-nfs, probably using a ramdisk and then
doing a chroot. You could even "export" the CD-ROM directly, but that
would probably render the access speed to it quite low on simultaneous
requests. You could be interested in having a look into the
Linux Terminal Server Project at www.ltsp.org, it works right that
way. Creating the RAM-Disk will be a bit of a difficulty, but there
should also be docs on what you need on that initrd (initial ramdisk)
with the LTSP. With some luck, all your machines to boot are based on
the same hardware (or at same networking cards, which will the only
part linux needs to be configured for specially in a computing
cluster, I think) so they can all use the same filesystem.

Of course you will have to use DHCP, as in other cases, the clients
could not be distinguished (same config files), but that will be the
case up to now, as the CD-ROMs used are exact copies of each other,
aren't they?

BTW not to forget the "trickiest part" (for beginners on etherboot at
least) - how to boot the machines? As they have fast ethernet, you
usually plug a boot rom onto the NIC boards (not to forget to enable
these with vendor specific software, some older models require an
explicitely enabled rom slot), configure DHCP and TFTPD and enjoy. For
the first tests, use www.rom-o-matic.net to generate a floppy bootable
ROM image for your NICs, RTfineM. Ask again if you have proceeded.

> This could allow us to bring the cost of
> Nodes down to $100 USD and utilize 486 DX PCs as well.

Hmmm... about 105€ per node, that's really cheap. Even having access
to resellers' prices, as a private question, what do you put into that
boxes? Of course, used 486 won't need that much investment.

Best regards,

 Anselm Martin Hoffmeister
 Stockholm Projekt Computer-Service, Sankt Augustin DE
 mailto:eth...@ho...