[libvirt] [RFC] VM which uses macvtap will not respond ping request when being migrated

[Laine Stump]

On 03/18/2014 02:12 AM, Wangrui (K) wrote:
> A vm which uses macvtap will not respond ping request, when the vm is being migrated. 
>
> I found that on the destination side the macvtap will send a IPv6 packet at the begin of migration to update the route table in switch, however VM is still on the src.
>
> In this case , what can I do to avoid VM's network disconnection
>

Can you provide more details on this? What are the versions of libvirt,
qemu, and kernel on your host system? Can you provide the <interface>
section of the guest's config?

Does this only occur when the guest has IPv6 enabled, and only for an
IPv6 ping? What is the packet that is sent? At the beginning of the
migration the guest is not running on the destination, and the host has
no idea what the guest's IPv6 (or v4) address might be, so it can't send
a IPv6 packet on behalf of the guest. The only thing I can think of
could be something to do with the link-local address (the fe80:...
address that is used for IPv6's discovery and autoconf protocols).