On 03/25/2011 12:43 AM, Osier Yang wrote:

�� 2011��03��24�� 19:16, ������ ����:

...

When a vm move from one VLAN(e.g. VLAN 1) to another VLAN (e.g. VLAN 2), it is needed to restart the network connection of guest OS, so that it can begin a dhcp discover and get a new ip again. But i can't find the way to restart the guest os's network connection by libvirt (neither python API nor virsh command). Is any other ways?

Hi,

Won't virt-manager (if has) in your guest try to restart the network?

...

PS: i found that the VirtualBox can detach the cable of VMs and re-attach so that the guest OS will recognize and restart a dhcp discover when the cable re-attach. I guess the KVM will have some feature like that , is anybody know something about that?

Libvirt supports similar function. # virsh detach-interface # virsh attach-interface

Or # virsh detach-device # virsh attach-device

the difference between "*-device" and "*-interface" is the accepted arguments, the later one accepts interface xml.

Those present to the guest as if the interface itself was being unplugged. What he's looking for is a way to just emulate a loss of carrier on the interface (ie unplugging the *cable*). There is an open bug for that: https://bugzilla.redhat.com/show_bug.cgi?id=643373 but no work has been done on it yet. Note that the required qemu monitor command does exist: "set_link XXX off" and "set_link XXX on", but I was unable to get a form of "virsh qemu-monitor-command" that could make this work.