unable to migrate non shared storage in tunneled mode

[Vjaceslavs Klimovs]

I've filed https://gitlab.com/libvirt/libvirt/-/issues/65 for this
issue, thanks again for your help.

On Mon, Aug 17, 2020 at 7:38 PM Vjaceslavs Klimovs <vklimovs at gmail.com> wrote:
>
> On Mon, Aug 17, 2020 at 3:24 AM Peter Krempa <pkrempa at redhat.com> wrote:
> >
> > On Sat, Aug 15, 2020 at 15:38:19 -0700, Vjaceslavs Klimovs wrote:
> > > Hey all,
> > > With libvirt 6.5.0 and qemu 5.1.0 migration of non shared disks in
> > > tunneled mode does not work for me:
> > >
> > > virsh # migrate alpinelinux3.8 qemu+tls://ratchet.lan/system --live
> > > --persistent --undefinesource --copy-storage-all --tunneled --p2p
> > > error: internal error: qemu unexpectedly closed the monitor: Receiving
> > > block device images
> > > Error unknown block device
> > > 2020-08-15T21:21:48.995016Z qemu-system-x86_64: error while loading
> > > state section id 1(block)
> > > 2020-08-15T21:21:48.995193Z qemu-system-x86_64: load of migration
> > > failed: Invalid argument
> > >
> > > This is both with UEFI and BIOS guests.
> >
> > The migration of storage using the qemu migration stream is not
> > supported by qemu when -blockdev is used. Since we can only transport
> > one stream when migrating with '-tunelled', it's no longer possible to
> > combine those two. Unfortunately automagic block migration was deemed a
> > legacy feature.
> >
> >
> > > I understand that newer ways of migrating non shared disks is via NBD
> > > directly with QEMU, however I am certain
> > > that this used to work before libvirt 6.0. There is a series of
> > > commits to /src/qemu/qemu_migration.c on Dec 8, 2019,
> > > could they have something to do with this?
> >
> > I presume those are my commits which fix the NBD migration though.
> > Unfortunately they can't fix the old one.
> >
> > > Is migration of non shared disks supported and supposed to work in
> > > tunneled mode or is it not a supported configuration
> > > and native NBD directly with QEMU should be used in all cases?
> >
> > NBD should be used nowadays. The old style storage migration was
> > neglected for a very long time now.
> >
>
> Thank you for the clarification, very helpful.
>
> Local libvirtd of course knows about --tunneled and -blockdev being
> used - would it be possible for it to provide a clear error message
> that this combination is not supported when such migration is
> attempted?