KVM doesn't send an arp announce after live migrating a domain

[Nils Cant <nils.cant@kangaroot.net>]

Hey guys,

not sure if this is a bug or a feature request. It's just something 
we've noticed and are having problems with.

We're using the qemu-kvm lenny-backports package on Debian 5.0.5.

When doing a live migration from the virsh shell, the server in question 
becomes unreachable because the ARP cache on our switches still thinks 
the server is on another port.

As soon as the server sends out some traffic, such as a ping, the ARP 
cache get's updated as expected. If it does nothing, the server remains 
unreachable until the ARP cache expires on the switches. (in our case 4 
hours)

We would like to be able to do live migration for customer machines on 
which we have no access, so we really need KVM to send out an ARP 
announcement/gratuitous ARP when doing a live migration.

Could anyone tell me if this is a bug in KVM, libvirt, or the debian 
qemu-kvm package? (or if I'm doing something wrong? :-) )

I've been tcpdumping the bridged network interfaces on the hosts while 
doing the migrate, and couldn't see any ARP broadcasts.

Debian 5.0.5
Kernel: 2.6.32-bpo.3-amd64
qemu-kvm                      0.12.4+dfsg-1~bpo50+2
libvirt0                      0.7.6-1~bpo50+1

migrate --live testserver qemu+ssh://192.168.1.3/system

Thanks in advance,

Nils