[libvirt] [RFC v1 0/6] Live Migration with ephemeral host NIC devices

[Daniel P. Berrange]

On Wed, May 13, 2015 at 10:05:24AM +0200, Peter Krempa wrote:
> On Wed, May 13, 2015 at 11:36:26 +0800, Chen Fan wrote:
> > my main goal is to add support migration with host NIC
> > passthrough devices and keep the network connectivity.
> > 
> > this series patch base on Shradha's patches on
> > https://www.redhat.com/archives/libvir-list/2012-November/msg01324.html
> > which is add migration support for host passthrough devices.
> > 
> >  1) unplug the ephemeral devices before migration
> > 
> >  2) do native migration
> > 
> >  3) when migration finished, hotplug the ephemeral devices
> 
> IMHO this algorithm is something that an upper layer management app
> should do. The device unplug operation is complex and it might not
> succeed which will make the current migration thread hang or fail in an
> intermediate state that will not be recoverable.

Agreed, that's what I have said in response to this suggestion many
times before. This kind of thing really falls into the realm of
usage policy, and we've long said that libvirt should focus on
providing the /mechanism/ and leave usage policy upto the management
application. There are many possible policies, and libvirt should
not be trying to decide which is best for all applications.

Regards,
Daniel
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