[libvirt] Block-migrate

[Daniel P. Berrange]

On Sat, Aug 07, 2010 at 03:55:10PM +0200, Ruben Kerkhof wrote:
> I've been playing with the new block-migrate feature, but am unable to
> get it to work.
> 
> [root at src ~]# virsh migrate --live --p2p  --tunnelled
> --copy-storage-all 4c5c75b9-decc-41c9-9296-20ca5bd5c355
> qemu://dst/system
> error: Unknown failure
> 
> /var/log/libvirt/qemu/4c5c75b9-decc-41c9-9296-20ca5bd5c355.log on the
> destination host shows:
> 
> bind(unix:/var/run/libvirt/qemu/qemu.tunnelmigrate.dest.4c5c75b9-decc-41c9-9296-20ca5bd5c355):
> Permission denied
> Migration failed. Exit code
> unix:/var/run/libvirt/qemu/qemu.tunnelmigrate.dest.4c5c75b9-decc-41c9-9296-20ca5bd5c355(-22),
> exiting
> 
> It seems that qemu is not able to write to that location.
> 
> [root at dst qemu]# ls -ld /var/run/libvirt/qemu/
> drwx------. 2 root root 4096 Aug  7 15:40 /var/run/libvirt/qemu/
> 
> As a workaround I gave qemu write permission, and now the block migrate starts.

Did the disk image files exist on the target before migration started ?
If not, then this is going to be falling foul of our security drivers
which prevent QEMU creating new files itself.

Also, a straw poll of people at the KVM forum yesterday determined that no
one had ever got  block migration to work, so it might be just broken in
QEMU

Daniel
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