On 01/03/2012 01:31 PM, Michal Privoznik wrote:

On 03.01.2012 14:39, Kees van Reeuwijk wrote:

...

Hello,

First of all, happy new year!

I am interested in the hot plugging facilities of libvirt, in particular in what qemu calls 'hot add' of network interface cards. (And also the reverse: hot unplugging/removing of NICs.)

I think I am overlooking something, but so far the best I have been able to find is:

http://libvirt.org/sources/virshcmdref/html/

and it is not entirely clear to me what the relevant virsh commands are. The most obvious choice seems to be the iface-* commands such as

http://libvirt.org/sources/virshcmdref/html/sect-iface-define.html

but these seem to be about physical rather than virtual network interfaces, and the documentation `needs to be written' anyway, and from the copyright notice the manual seems to be somewhat outdated by now.

Can you give me a little help with this? Is such hot plug/add functionality supported by libvirt in the first place? Is there some kind of overview document about this? What is the most authoritative documentation of this functionality? Is there a Java or C API to access this functionality?

Thank you for any help you can give me,

I think virsh attach-interface / detach-interface is what you are looking for. Another option is to write a little XML snippet and virsh attach-device it.

Additionally, I can vouch for at least a centos6 guest being able to properly respond to hotplug/remove for virtio NICs. It automatically runs the ifup for the interface as long as the MAC address is correct. I imagine this works for other O/S as well. I add/remove using virt-manager (which uses libvirt) so I don't know the specific virsh command... David