Re: naked machines

On Thu, 2005-09-22 at 13:07, massimiliano cialdi wrote:
> is it possible to run acluster in which some machines are "naked"?
> I mean a computer with only mother board (with an integrated NIC to
> boot up), cpu and ram; without any mass storage device (such hard
> disk, floppy or CD), keyboard, mouse and graphic card.

Yes, it's possible (at least if the BIOS of your naked machine is able
to bootup without graphic card and storage devices, "press any key to
continue" could be a serious problem when there's no keyboard ;).

You need an initrd with a basic filesystem image (to be loaded into RAM
at bootup) or you can mount all over NFS. You have to configure a DHCP
and a TFTP servers (on the masternode) and your nodes must have a
network card that support network booting (PXE).
The node's kernel must support the initial RAM disk
(CONFIG_BLK_DEV_INITRD) and, depending on your choice, the kernel level
autoconfiguration of the IP (CONFIG_IP_PNP, CONFIG_IP_PNP_DHCP) and the
root file system on NFS (CONFIG_ROOT_NFS).

You can find some howtos on the community contributions page (search for
"ltsp") and, for general DHCP+TFTP+PXE systems, all over the network.

...I'm not sure, but ClusterKnoppix should already supply such system
and it needs no effort to buildup a test cluster configured in this way,
give it a try.

There could be some issues concerning rootfs over NFS, browse the ml
archive for more info (related to some codes that don't like it, maybe).

Some time ago I found it useful to use the warewulf initrd image
(formerly nodefs, now vnfs) as a template to build my own initrd stuffed
with oM. I'm not sure it's still suitable for the same purpose, you can
take a look here: http://warewulf.lbl.gov/. Basically, you just need the
usual fs tree and some startup utility, sshd could be useful for remote
administration, other utilities could help as well. Of course you need
the userspace-tools package.

Hope this helps.

Ciao

Moreno





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