On Wednesday 16 April 2008 09:54:18 pm John Summerfield wrote:
> Jarod Wilson wrote:
> > On Wednesday 16 April 2008 10:31:13 am John Summerfield wrote:
> >> Jarod Wilson wrote:
> >>> On Wednesday 16 April 2008 05:55:32 am John Summerfield wrote:
> >>>> I don't want to assign an IP address in the kernel commandline, so it
> >>>> has to get one.
> >>>>
> >>>> At present, it doesn't do this, so netconsole doesn't work.
> >>>>
> >>>> Just for the hell of it, I added "ip=dhcp" as one does for nfs-root.
> >>>>
> >>>> Then, netconsole failed. After that, the kernel used dhcp to get an IP
> >>>> address.
> >>>>
> >>>> Now, if the kernel could get the IP address first, then netconsole
> >>>> would work and I'd be able to log this problem without fiddling around
> >>>> with serial cables and other computers.
> >>>
> >>> At first blush, I'm assuming this falls down because there isn't a dhcp
> >>> client built into the kernel. For nfs root, the dhcp client is actually
> >>> in the initrd, and I'm guessing netconsole wants to start up even
> >>> before the initrd has been unpacked.
> >>
> >> No, the kernel (if so built) doesn't require an initrd. This worked as
> >> far back as 2.2, maybe earlier. It might once have only done bootp, but
> >> it's had dhcp for years and years.
> >
> > Sorry, I wasn't clear, I was speaking purely in the Red Hat kernel case,
> > where CONFIG_IP_PNP is not set. Of course, re-reading with the context of
> > me talking about new things that may be enabled in post-F9 rawhide, I'm
> > guessing you were already aware of this, and were perhaps suggesting that
> > it be enabled as well...
>
> Ah, it seems you need some facts too:-)

I can certainly always use more... :)

> Here are the messages, along with some for context.
> BIOS EDD facility v0.16 2004-Jun-25, 6 devices found
> IP-Config: Failed to open ipddp0
> Sending DHCP requests .,. OK
> IP-Config: Got DHCP answer from 192.168.9.4, my address is 192.168.9.138
> IP-Config: Complete:
>        device=eth0, addr=192.168.9.138, mask=255.255.255.0, gw=192.168.9.4,
>       host=192.168.9.138, domain=demo.lan, nis-domain=(none),
>       bootserver=192.168.9.4, rootserver=192.168.9.4, rootpath=
[...]
> This is the kernel: Linux version 2.6.25-rc1, and
> [EMAIL PROTECTED] tmp]# grep ^CONFIG_IP_  25.config
[...]
> CONFIG_IP_PNP=y
> CONFIG_IP_PNP_DHCP=y

I asked around in Fedora-land about this a bit yesterday...

> Now, since we're on an enterprise list and supposedly talking about
> enterprise linux, and because I speculate an RHEL6 beta might be
> announced soon...
>
> I think that it would be good if netconsole worked the way I thought it
> would.
[...]
> A drawback is that the NIC's driver has to be in the kernel for ip=dhcp
> to work. I presume the same applies for this.

Yes, as I understand it, the NIC driver has to be up and running for 
netconsole to work (netconsole relies on a polling mode feature that has to 
be implemented in each NIC driver), so to make this doable, we'd have to turn 
on the in-kernel dhcp server and build all netconsole-capable NIC drivers 
into the kernel. I'm guessing chances are slim that'll happen, but I'm not 
guessing in any official capacity. :)

-- 
Jarod Wilson
[EMAIL PROTECTED]

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