Bringing up network interface without IP configured in Debian, for XEN dom0

Question

I have 3 NICs that I want to be seen by my domU, even though they're not configured in dom0.

Here's my sample lines from interfaces file

auto lo
iface lo inet loopback

# Local network, cable labeled M3
auto eth0
allow-hotplug eth0
iface eth0 inet static
        address 192.168.1.184
        netmask 255.255.255.0
        gateway 192.168.1.1

# cable labeled M1
auto eth1
allow-hotplug eth1
iface eth1 inet manual
        hwaddress ether 00:19:5B:33:86:D5
        up ifconfig eth1 up

# cable labeled M2
auto eth2
allow-hotplug eth2
iface eth2 inet manual
        hwaddress ether 00:19:5B:33:86:D3
        up ifconfig eth2 up

I'm trying to use multiple bridge configuration with xend, but it complains about the "Link not in running state" and interface being down, although I can see them in ifconfigs' output.

What are my options to make those NICs visible in domU without configuring them in dom0?

Solution

Oh dear... I think you're trying to use the Xen bridging stuff, which is just dire. Set network-script network-dummy in xend-config.sxp, then go with this config:

iface lo
iface lo inet loopback

# Local network, cable labeled M3
auto eth0
allow-hotplug eth0
iface eth0 inet static
    address 192.168.1.184
    netmask 255.255.255.0
    gateway 192.168.1.1

# cable labeled M1
iface eth1 inet manual
    hwaddress ether 00:19:5B:33:86:D5

# cable labeled M2
iface eth2 inet manual
    hwaddress ether 00:19:5B:33:86:D3

auto br-eth1
iface br-eth1 inet manual
  bridge_ports eth1

auto br-eth2
iface br-eth2 inet manual
  bridge_ports eth2

What you then do is tell the domUs to use either the br-eth1 or br-eth2 bridge (as appropriate). Given that you've got cable labelling happening, I'd change the bridge names to something more useful, like perhaps m1 and m2.

Comments

[womble]

Show us your entire /e/n/interfaces file. I have a strong suspicion you're doing something really unwise, because the same layout works fine for me on my dom0s.

[Karolis T.]

Updated as per your request

[Antoine Benkemoun]

I agree. As a rule of thumb, avoid using Xen networking scripts. It's not so complex to do things yourself and leads to much better results.

[Karolis T.]

Thanks a lot, the idea of manually bridging interfaces didn't even occur to me. What is wrong with XEN native bridging scripts?

[womble]

They're excessively complicated, and don't follow standard conventions for bridging configuration, which makes it harder to manage and maintain.

[Jeff Snider]

I can't vote this up enough. The Xen bridge setup scripts are just dreadful.