Ethernet bridging weirdness

[Serge E. Hallyn]

Quoting Douglas Stanley (douglas.m.stanley at gmail.com):
> Hello all,
> 
> I'm about at my wit's end, and I really hope some one might be able to
> shed some light on this topic for me.
> 
> I have two physically identical servers, both running 10.04.1, both
> are completely up to date. Both are set up to be kvm hosts. On both
> machines, I have an IDENTICAL /etc/network/interfaces, the only
> difference being two lines where ip addresses are specified.
> 
> The problem is, that both machines need a bridge set up on boot, so
> that virtual machines can access it. One machine works 100% fine, the
> other, the second bridge never comes up!
> 
> My /etc/network/interfaces file can be seen at:
> http://gist.github.com/579592
> 
> Also, I just did a fresh re-install of 10.04.1, and performed the
> updates on the machine that isn't working, thinking that maybe I did
> something slightly different during the initial install. But it still
> doesn't work.
> 
> If I type:
> sudo ifup br1
> I get: "ifup: interface br1 already configured". But, ifconfig doesn't
> list either my eth2 or my br1 devices. Also, brctl show doesn't list
> my second bridge. But, if I edit /var/run/network/ifstate and remove
> the br1=br1 line, then run "sudo ifup br1", it comes up just fine.
> Similarly, if I "sudo ifdown br1;sudo ifup br1" that also works.

Well br1 is manual, without a specified address.  As opposed to br0
which is static with an address.  So I wouldn't expect it to show up
with ifconfig.  Does it not show up with 'ifconfig -a' or 'brctl show'?
Can you not specify an address for it (either using ifconfig or with
dhclient)?

> Any idea why it isn't coming up automatically on boot, when my other

Because 'manual' means 'unconfigured', different from 'static' which
means manually pre-configured.

> identical machine does just fine? Or even where I might look to try
> and figure it out myself? There are no error messages in any of the
> log files that I could find. I'm truly stumped!
> 
> Thanks,
> Doug
> 
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