[libvirt] Canging bridge names on live migration

[Laine Stump]

On 06/10/2015 02:06 PM, Philipp Hahn wrote:
> Hello,
>
> On 03.06.2015 13:18, seitan wrote:
>> i wonder, if there's a possibility to change a name of a shared interface in
>> virtual machine config, while doing migration.
>> The problem is:
>> hypervisor1 (source) uses shared interface name  "br0".
>> hypervisor2 (target) uses shared interface name "br500".
>> Live migration fails, because target hypervisor does not have "br0" interface.
> libvirt supports some hook scripts, which can be used to re-write the
> XML file during live migration. Have a look at
> <http://docs.univention.de/uvmm-4.0.html#uvmmext:kvm:migrate>, which
> should work similarly for your scenario.

In the general case of "I need to modify the XML" you can use migration
hooks to modify it, but in the case described in this question you don't
need to modify the XML. Instead, just create an unmanaged libvirt
network on each host, with the same network name, but each pointing to a
different bridge. Then the XML can remain the same.

This same question was also asked simultaneously on libvirt-users, but
in a separate message so the replies for that didn't come to this list.
It looks like the poster used some sort of web interface at gmane.org
which isn't smart enough to use the same message ID when crossposting.
Here is a pointer to my response in libvirt-users:

   https://www.redhat.com/archives/libvirt-users/2015-June/msg00015.html