[CentOS-virt] xenbr0 vs. virtbr0

Sun Mar 23 23:31:14 UTC 2008
Kai Schaetzl <maillists at conactive.com>

Ross S. W. Walker wrote on Thu, 20 Mar 2008 11:54:30 -0400:

> I was confused initially by this too, but it turns out that virbr0 is the
> libvirt managed interface (dnsmasq and non-xen qemu) and libvirt managed
> clients use it by default. It should be pre-set with subnet

Yes, that is the subnet the VMs get IPs from. I wasn't aware that dnsmasq is on 
by default, but you are right. But there is no configuration for this subnet
in the dnsmasq configuration. But there is configuration for this subnet in 
/etc/libvirt, so it seems to get the IP not from a dhcp call. (That would also 
explain why dhcp doesn't work over xenbr0 for me.)

> xenbr0 is the Xen managed bridge and it comes with no default IP and it's
> characteristics are managed purely through the xend configuration.

and no way to get it to do dhcp?

> I believe the virtual network is the standard xen network interface config
> and the shared network is the virbr0 thing, but don't quote me on that,
> as you said documentation isn't plentiful here.

Well, if I use "virtual network" I get virbr0. I cannot use the "shared 
network" thing as it doesn't show any devices, so I don't know how it might 
work :-(

> > help is no help for this, it's empty for this section.
> This page left intentionally blank?

;-). I see that there is some information about libvirt on libvirt.org, but 
nothing about this. :-(


Kai Schätzl, Berlin, Germany
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