Re: [Xen-users] Re: Communicating with VM before Network is configured.

[tbrown@xxxxxxxxxxxxx]

On Tue, 18 Jul 2006, Chris McKeever wrote:

> > Then again, I don't know why the xen code couldn't convert network
> > configuration parameters into the kernel auto-config format. I don't know
> > if it is a good idea, but it seems possible.
>
> >From what I have seem - it is supposed to:
>
> http://www.nabble.com/IP-configuration-for-domU-ignored-t1779301.html
>
> but in this case, it doesnt - for me at least.

unless you're running into the same problem he describes ... which is that
the server parameter is not being specified, and as such the kernel
doesn't consider it a valid ip config and doesn't pre-configure eth0 for
you.

he covers it:
   ip=172.28.77.99::172.28.77.1:255.255.255.0:knscsl021-vm3:eth0:off
vs
   ip=172.28.77.99:1.2.3.4:172.28.77.1:255.255.255.0:knscsl021-vm3:eth0:off

If I set the ip= parameter manually, ip-config fails... If I spec an ip=
value in my config file, then xen builds an ip=... kernel parameter line
which supplies an "nfs_server" of 1.2.3.4 by default

>> AFAIK, The server-ip string seems to be mandatory, and 0.0.0.0 does not
>> work.
>
>some reference to leaving it blank may work as well (untested):
>ip=<client-ip>::<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>


Hhmm, maybe, or maybe it doesn't and this is the reason why.
"seems to be mandatory" would imply that I tried leaving it
out (I did) ... and :: would be the only way to do that.

OK. I've just done some testing. as far as I can see, xen-3.0.2-2
does fill in a nfs_server entry of 1.2.3.4 and should avoid the
problem I'm describing and that Pablo talks of at the top of that page.
But at the bottom he says his problem went away with a recompiled kernel.


Anyhow, if you are getting an ip=... kernel parameter with a blank
nfs-server entry, you can try adding this to your config file:

   nfs_server="4.3.2.1"

When you boot, there should be some "clues"...

e.g.

   Using config file "test.ip".
   Started domain test
   Linux version 2.6.16-xenU (root@xxxxxxxxxxxxxxxxxx) (gcc version
   3.4.5 20051201 (Red Hat 3.4.5-2)) #3 SMP Tue Jul 18 11:39:43 PDT
   <snip>
Kernel command line:
ip=192.168.2.254:5.4.3.2:192.168.2.86:255.255.255.0::eth0:off
root=/dev/nbd0 ro NBDHOST=65.39.183.43 NBDPORT=8000 single
   <snip>
   Using IPI No-Shortcut mode
IP-Config: Complete:
      device=eth0, addr=192.168.2.254, mask=255.255.255.0, gw=192.168.2.86,
     host=192.168.2.254, domain=, nis-domain=(none),
     bootserver=4.3.2.1, rootserver=4.3.2.1, rootpath=
   Freeing unused kernel memory: 132k freed
   Red Hat nash version 4.2.1.6 starting

I've left shifted the clues... e.g. the kernel command line and
the IP-Config: settings. If you're not getting an IP-Config
setting, then the either your kernel isn't compiled right, or
your ip= kernel parameters are not recognized as legit.

obviously, my root=/dev/nbd0 and the NBD* parameters are not going to
be the same in your config...

... damn, I'm out of "day". I hope the above makes sense, it was written
in about four passes.

-Tom


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