CentOS - Feb 2013 - weird issue with qemu-kvm network...

Hello CentOS mailinglist
I am running CentOS 6.3 with qemu-kvm and libvirt.
I was experimenting with bridged VM networking. Usually the VMs run over 
the network device virbr0.
So i created a new bridge with brctl and added my eth0 to that bridge. 
Not touching virbr0 or it's configuration at all.
Then i edited the configuration xml from my VM with 'virsh edit vmname'.
After that i decided to restart my server, basically just to 'reset' my 
network. I know, that's not necessary. But it's easier than risking 
connection loss and having to get physical access to the server ;)

After the restart my virbr0 network device was gone!
cat /var/log/dmesg | grep virbr0 returned nothing.
cat /var/log/messages | grep virbr0 brought up nothing aswell.

I tried to reinstall all relevant packages with
yum reinstall qemu-kvm python-virtinst virt-top virt-viewer libvirt 
libvirt-client libvirt-python qemu-kvm-tools

But with no success :(

Does anyone have an idea how to recreate the default virbr0?
Is it doable via virsh? I don't have a DE installed on this server, so 
no virtual-manager. I am willing to go that far if it's worth it though.

>
> Does anyone have an idea how to recreate the default virbr0?
> Is it doable via virsh? I don't have a DE installed on this server, so
> no virtual-manager. I am willing to go that far if it's worth it
though.
>
You don't need a DE for that just yum install xauth virt-manager and ssh -X
to forward it to your local X server.

Although I do a fair amount from virsh and editing XML if you don't use a
cluster manager/tool/IaaS like ovirt, openstack, archipel etc virt-manager
is too useful not to have - especially to get console access to VMs nicely.

I'm home now but if you're struggling on the bridge part come Monday
send
me a mail and I'll send you my server network configs to give you a start
on this.