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

Dr. David Alan Gilbert dgilbert at redhat.com
Wed May 13 08:08:39 UTC 2015


* Peter Krempa (pkrempa at redhat.com) 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.

However you wouldn't want each of the upper layer management apps implementing
their own hacks for this; so something somewhere needs to standardise
what the guest sees.

Dave

> I'll point the places out in the actual patches.
> 
> > 
> > 
> > TODO:
> >   keep network connectivity on guest level by bonding device.
> 
> This is out of scope for libvirt since we don't really know what is
> running inside the vm.
> 
> > 
> > Chen Fan (6):
> >   conf: add ephemeral element for hostdev supporting migration
> >   qemu: Save ephemeral devices into qemuDomainObjPrivate
> >   qemu: add check ephemeral devices only for PCI host devices
> >   migration: Migration support for ephemeral hostdevs
> >   managedsave: move the domain xml handling forward to stop CPU
> >   managedsave: add managedsave support for ephemeral host devices
> 
> Peter


--
Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK




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