F20 beta virt-manager cannot create bridged network interface

[Cole Robinson]

On 01/26/2014 11:39 PM, Shawn Starr wrote:
>> On 11/18/2013 07:13 PM, Richard Michael wrote:
>> Hello,
>>
>> I've just installed F20 beta x64 and applied all updates.
>>
>> I'm attempting to create a bridge network interface in virt-manager
>> (0.10.0).  I complete the "Configure network interface" dialog, and
>> when I click "Finish" I receive an "Input Error" with message:
>>
>> 'str' object has no attribute 'XMLDesc'
>>
> 
> 

I missed the original mail, but that bit is just a virt-manager issue, fix is
upstream and waiting for backport now. It's tracked at the bug you mention below:

https://bugzilla.redhat.com/show_bug.cgi?id=1048351

> 
> 
> Worse, NetworkManager bridge is broken in that the bridge interface never gets
> the IP address and if libvirtd tries to bring up a VM instance it never gets
> network connectivity.
> 
> 

Can't blame networkmanager here, this is just more example of
virt-manager/libvirt/netcf not playing nice with NetworkManager which has been
a recurring problem.

NetworkManager grew more explicit support for bridges in the past few fedora
cycles, so maybe something that used to work has regressed.


> 
> One additional bad thing (which I just fixed), was my original working bridge
> setup. libvirtd silently fails to autostart a KVM instance until I destroyed
> my bridge setup, recreated it via:
> 
>  
> 
> # nmcli connection add con-name Bridge type bridge ifname bridge0
> 
> # nmcli connection add con-name Slave type ethernet mac AA:BB:CC:DD:EE:FF
> 
>  
> 
> This alone will not set/bind the IP on the bridge0 interface but on the actual
> interface, so while libvirt now autostarts the KVM VM instance, the VM has no
> external network connectivity as the bridge0 interface has no IP assigned to it...
> 
>  
> 
> I've encountered various problems with bridge networking and
> libvirtd/NetworkManager/virt-manager and now with systemd-networkd (which does
> bridging)...
> 
> 

This is all news to me, please put all the details in a bug report and CC me.
You can start with filing it against libvirt and we can triage from there.

> 
> What exactly *IS* our official setup for Bridging support??
> 

What was it ever, really? You could do it with virt-manager but that could
also fall over in multiple ways. You could do it with sysconfig scripts but
that required stopping NetworkManager which is basically impossible on a
modern desktop.

Nowadays there should be a NetworkManager UI solution but it hasn't been
advertised very much and isn't entirely straightforward:

https://lists.fedoraproject.org/pipermail/devel/2014-January/194003.html

I think someone needs to blog about it with screenshots, then we can link to
it with all the fedora virt and upstream libvirt pages.

>  
> 
> We've failed hard in 19/20 on bridging and it's burnt me so much, I want to
> add a test case for Fedora 21 on this, where can I do this?
> 

Fedora test day test case template:
http://fedoraproject.org/wiki/Template:QA/Test_Case

Maybe add a network manager bridge UI test case for the gnome test day, but
you'll have to check with the folks who run it. Or if there's a networking
test day.

I run the virt test day, and I've made a note to add test cases for setting up
a bridge. I think there's an old one but it should be bumped and modernized.

- Cole