Bug#413601: Xen domUs vs. udev
Thomas Schwinge
Severity: important
X-Debbugs-CC: pkg-xe...@lists.alioth.debian.org
Hello!
When installing the udev package in a Xen domU, ``strange'' things
happen.
The following is a bit of guesswork, some hard facts are probably
missing, but I hope that the udev and / or Xen maintainers can make some
sense out of it. I'm for now happy with having a usable Xen server
again...
The virtual ethernet devices that the Xen dom0 creates for providing net
access to a domU will have (unless overridden) a rather random mac
address. Now, when having udev installed in a domU (by the way: the
problem seems to not show up with version 0.103-2) this has the effect
that (guesswork follows) udev thinks on each system (re)start that a new
ethernet device is available. This can be seen in (a) the device no
longer being called `eth0', but `eth1', `eth2' on next restart and so on
and in (b) that the list in a domU's
`/etc/udev/rules.d/z25_persistent-net.rules' is getting longer and
longer:
#v+
[...]
# Xen virtual device (vif)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:16:3e:07:f2:cb", NAME="eth11"
# Xen virtual device (vif)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:16:3e:66:be:47", NAME="eth12"
# Xen virtual device (vif)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:16:3e:55:07:c7", NAME="eth13"
#v-
If you have had a simple...
#v+
auto eth0
iface eth0 inet dhcp
post-up ethtool -K eth0 tx off
#v-
... in the domU's `/etc/network/interface' that will obviously no longer
work, as the device won't be called `eth0' any longer, thus rendering the
domU's network connection unusable after having installed the udev
package.
A workaround is to either use udev version 0.103-2 in the Xen domUs or
completely remove the udev package from there.
I also think that it was neccessary to downgrade the dom0's version of
udev to 0.103-2 and rebuild the initrds to get things working again, but
I'd have to double-check that, which I'm not going to do right now.
(It's late already...)
Regards,
Thomas
Marco d'Itri
> A workaround is to either use udev version 0.103-2 in the Xen domUs or
I higly doubt this, I reviewed the changes and I could not find anything
which would make udev ignore xen interfaces.
> completely remove the udev package from there.
Or RTFM and delete /etc/udev/rules.d/z45_persistent-net-generator.rules .
I am inclined to consider this a configuration error.
--
ciao,
Marco