Re: make module loading by boot installboot patchable?

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

apb%cequrux.com@localhost said:
> I thought some people had diskless booting working with modular
> kernels.

It _can_ be done, certainly, but it requires extra work. As said,
if one puts a new pxeboot.bin into an existing setup it fails.
(I was forced to do so because a new board I got uses some strange
BIOS console redirection and thus needs the serial I/O address
wired into pxeboot.)
It will most likely also fail in setups as described in the
pxeboot(8) manpage.

Honestly, the whole idea of booting a kernel without NFS built in
in a diskless setup is insane. It only adds complexity for no
gain, and slows down the boot process. (More than with disk boot,
in both cases: diskless boot is more complex anyway due to the
DHCP server and TFTP in between, and the slowdown is worse because
DHCP transactions etc take much more time than a file lookup
on disk.)

> > to make a diskless system boot unattended and reliably, module
> > loading needs to be disabled for pxeboot in the standard case
> Why is that the only possible solution to the problem?

It is not the only possible solution, bit I think a reasonable one.
The bootloader could also be taught to find out whether the
kernel image just loaded already has NFS built in, but I'd fear
compatibility problems and general fragility.
First goal should be that pxeboot just works with a simple standard
setup. And with a patchable bit someone who wants to play with
an nfs module can switch it on -- this is likely the easiest part
of the whole thing.

best regards
Matthias



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