3

I'm running a Lenny Xen dom0 hosting multiple virtual machines in a routed IP setup. To get an additional private subnet, I created the bridge xenbr0 in the dom0 with the following commands:

brctl addbr xenbr0 ifconfig xenbr0 10.0.0.1 netmask 255.255.255.0 ifconfig xenbr0 up

This works as expected, and domU interfaces are added to the bridge by Xen on VM start. My only problem is: how the heck do i specify this configuration in /etc/network/interfaces that it remains permanent and the bridge is available after a reboot? I tried the following config as found on a lot of tutorials:

auto xenbr0 iface xenbr0 inet static address 10.0.0.1 netmask 255.255.255.0 network 10.0.0.0 broadcast 10.0.0.255 bridge_stp no

I get 2 different errors, depending on if the bridge already exists or not. If it doesn't exist:

root@dom0:~# brctl show bridge name bridge id STP enabled interfaces root@dom0:~# /etc/init.d/networking restart Reconfiguring network interfaces...if-up.d/mountnfs[eth0]: waiting for interface xenbr0 before doing NFS mounts (warning). SIOCSIFADDR: No such device xenbr0: ERROR while getting interface flags: No such device SIOCSIFNETMASK: No such device SIOCSIFBRDADDR: No such device xenbr0: ERROR while getting interface flags: No such device xenbr0: ERROR while getting interface flags: No such device Failed to bring up xenbr0. done.

And if it exists:

root@dom0:~# brctl show bridge name bridge id STP enabled interfaces xenbr0 8000.000000000000 no root@dom0:~# /etc/init.d/networking restart Reconfiguring network interfaces...if-up.d/mountnfs[eth0]: waiting for interface xenbr0 before doing NFS mounts (warning). RTNETLINK answers: File exists Failed to bring up xenbr0. done.

Could anyone point me in the right direction please? The bridge works fine when created manually, i just need the right config file entries. The most tutorials I found add some devices to the bridge in the config, is that maybe the problem why it is not working? I don't have any interfaces I want to add to the bridge on creation as they get added later on VM start...

Thanks, Mathias

Improve this question
2
  • Have you checked the Xen mailing list and wiki.xensource.com/xenwiki/XenNetworking ? Commented Jun 14, 2010 at 22:37
  • Sure, the setup works as desired. I just need to know how to setup the bridge in /etc/network/interfaces to have it available on a dom0 reboot without having to manually create the bridge over the shell. So it's not a Xen specific problem, but debian-related (I just need to know the right config file syntax). Commented Jun 14, 2010 at 23:16

3 Answers 3

Reset to default
5

You seem to miss the most important line:

auto xenbr0 iface xenbr0 inet static bridge_ports eth0 eth4 eth7 # bridge traffic between these interfaces bridge_stp no address 10.0.0.1 netmask 255.255.255.0 network 10.0.0.0 broadcast 10.0.0.255

man says: If you need to specify the interfaces more flexibly, you can use the following syntax (most useful on a Xen dom0):

 bridge_ports regex (eth|vif).*

This means to evaluate (as in egrep(1)) the expressions that follow after "regex".

Improve this answer
1
  • I don't have any ports to bridge when the bridge is created as the only bridged interfaces belong to the VMs which get created later. However, i re-checked my config and noticed that I had 2 "up route add..." entries standing below the bridge config which belonged to the eth0 interface. I also added "bridge_ports none" to the bridge config and now it works :) Commented Jun 16, 2010 at 19:59
1

How about a script that runs after startup to perform the commands you want?

Improve this answer
1
  • Sure, that would be possible, but using debian's built in network scripts would be the cleaner way. Commented Jun 15, 2010 at 7:40
0

You may need to remove the network-manager package. It often interferes with manual interface settings.

Improve this answer

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.