[libvirt] [libvirt-users] cannot perform tunnelled migration without using peer2peer flag

[Eric Blake]

On 07/19/2011 03:23 AM, Daniel P. Berrange wrote:
> On Mon, Jul 18, 2011 at 01:11:42PM -0600, Eric Blake wrote:
>> On 07/18/2011 04:11 AM, Osier Yang wrote:
>>> 于 2011年07月18日 10:07, zhang xintao 写道:
>>>> Dear All
>>>> I try to migration a kvm guest os to another host failed
>>>> server: ubuntu 11.04 server
>>>> virsh:migrate --live --tunnelled vm1 qemu+ssh://192.168.10.3/system
>>>> error:Requested operation is not valid:cannot perform
>>>> tunnelled migration without using peer2peer flag
>>>
>>> The error tells you all, you need to use "--p2p".
>>
>> That said, why can't virsh be smarter, and automatically request the
>> right underlying flags without making the user also type --p2p?  Any
>> problems with this patch?
>
> It was done to leave open the possibility of supporting a
> TUNNELLED mode, which was independant of P2P mode in the
> future. It isn't entirely likely, but I didn't want to lock
> ourselves out of it with this kind of patch

But if we ever reach that point, could we then revert this patch at that 
time, to where the user once again has to tell virsh both --p2p and 
--tunnelled?  Or would such a change be considered a regression in 
behavior at that time for existing scripts that were foolishly relying 
on the UI shortcut, and hence virsh should never learn the UI shortcut 
in the first place?  If the latter, then we should revert the patch that 
just went in so that 0.9.4 doesn't lock us into causing a future regression.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org