[Qemu-devel] qemu <-> libvirt interaction broken

[Qemu-devel] qemu <-> libvirt interaction broken

[Gerd Hoffmann]

  Hi,

Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
libvirt feature detection, my guests fail to start with this message:

error: Failed to start domain fedora-org-virtio
error: internal error qemu does not support SGA

Running libvirt-0.10.2-2.el6.x86_64

cheers,
  Gerd

Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Peter Maydell]

On 22 October 2012 14:28, Gerd Hoffmann <kraxel@redhat.com> wrote:
> Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
> libvirt feature detection, my guests fail to start with this message:
>
> error: Failed to start domain fedora-org-virtio
> error: internal error qemu does not support SGA
>
> Running libvirt-0.10.2-2.el6.x86_64

Yeah, this is the commit that means you need an updated libvirt
from this point on (and in particular for qemu-1.3).

-- PMM

Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Gerd Hoffmann]

On 10/22/12 15:51, Peter Maydell wrote:
> On 22 October 2012 14:28, Gerd Hoffmann <kraxel@redhat.com> wrote:
>> Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
>> libvirt feature detection, my guests fail to start with this message:
>>
>> error: Failed to start domain fedora-org-virtio
>> error: internal error qemu does not support SGA
>>
>> Running libvirt-0.10.2-2.el6.x86_64
> 
> Yeah, this is the commit that means you need an updated libvirt
> from this point on (and in particular for qemu-1.3).

Well, only problem is that 0.10.2 already is the latest libvirt release.
 Was it really intentional to break things like this?

cheers,
  Gerd

Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Peter Maydell]

On 23 October 2012 08:03, Gerd Hoffmann <kraxel@redhat.com> wrote:
> On 10/22/12 15:51, Peter Maydell wrote:
>> On 22 October 2012 14:28, Gerd Hoffmann <kraxel@redhat.com> wrote:
>>> Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
>>> libvirt feature detection, my guests fail to start with this message:
>>>
>>> error: Failed to start domain fedora-org-virtio
>>> error: internal error qemu does not support SGA
>>>
>>> Running libvirt-0.10.2-2.el6.x86_64
>>
>> Yeah, this is the commit that means you need an updated libvirt
>> from this point on (and in particular for qemu-1.3).
>
> Well, only problem is that 0.10.2 already is the latest libvirt release.
>  Was it really intentional to break things like this?

This change was postponed to after 1.2 was released to
give libvirt a chance to wean itself off parsing our --help
output. I took Eric's Reviewed-by as an indication he was
happy with it going in now from the libvirt side...

-- PMM

Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Gerd Hoffmann]

On 10/23/12 10:19, Peter Maydell wrote:
> On 23 October 2012 08:03, Gerd Hoffmann <kraxel@redhat.com> wrote:
>> On 10/22/12 15:51, Peter Maydell wrote:
>>> On 22 October 2012 14:28, Gerd Hoffmann <kraxel@redhat.com> wrote:
>>>> Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
>>>> libvirt feature detection, my guests fail to start with this message:
>>>>
>>>> error: Failed to start domain fedora-org-virtio
>>>> error: internal error qemu does not support SGA
>>>>
>>>> Running libvirt-0.10.2-2.el6.x86_64
>>>
>>> Yeah, this is the commit that means you need an updated libvirt
>>> from this point on (and in particular for qemu-1.3).
>>
>> Well, only problem is that 0.10.2 already is the latest libvirt release.
>>  Was it really intentional to break things like this?
> 
> This change was postponed to after 1.2 was released to
> give libvirt a chance to wean itself off parsing our --help
> output.

Yea, I know this has been the plan for a long time and I agree that it
is a good move.

Only problem is that the switch didn't happen yet.  The bits might be
landed in libvirt/master, but there is no release with this yet and thus
libvirt versions using QOM for feature detection didn't find the way yet
into distributions.

IMO it is a bit early to stop caring about -help output compatibility in
qemu.

cheers,
  Gerd

Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Anthony Liguori]

Gerd Hoffmann <kraxel@redhat.com> writes:

> On 10/23/12 10:19, Peter Maydell wrote:
>> On 23 October 2012 08:03, Gerd Hoffmann <kraxel@redhat.com> wrote:
>>> On 10/22/12 15:51, Peter Maydell wrote:
>>>> On 22 October 2012 14:28, Gerd Hoffmann <kraxel@redhat.com> wrote:
>>>>> Commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8 appearently breaks the
>>>>> libvirt feature detection, my guests fail to start with this message:
>>>>>
>>>>> error: Failed to start domain fedora-org-virtio
>>>>> error: internal error qemu does not support SGA
>>>>>
>>>>> Running libvirt-0.10.2-2.el6.x86_64
>>>>
>>>> Yeah, this is the commit that means you need an updated libvirt
>>>> from this point on (and in particular for qemu-1.3).
>>>
>>> Well, only problem is that 0.10.2 already is the latest libvirt release.
>>>  Was it really intentional to break things like this?
>> 
>> This change was postponed to after 1.2 was released to
>> give libvirt a chance to wean itself off parsing our --help
>> output.
>
> Yea, I know this has been the plan for a long time and I agree that it
> is a good move.
>
> Only problem is that the switch didn't happen yet.  The bits might be
> landed in libvirt/master, but there is no release with this yet and thus
> libvirt versions using QOM for feature detection didn't find the way yet
> into distributions.
>
> IMO it is a bit early to stop caring about -help output compatibility in
> qemu.

It was announced.  There's been plenty of time to adapt.

If you're using QEMU from git, it's reasonable to require libvirt from
git IMHO.

By the time 1.3 goes out, there should be a libvirt release with the
necessary support so if your using distro packages, you'll never notice.

Regards,

Anthony Liguori

>
> cheers,
>   Gerd

Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Eric Blake]

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On 10/23/2012 06:47 AM, Anthony Liguori wrote:

>>>
>>> This change was postponed to after 1.2 was released to
>>> give libvirt a chance to wean itself off parsing our --help
>>> output.
>>
>> Yea, I know this has been the plan for a long time and I agree that it
>> is a good move.
>>
>> Only problem is that the switch didn't happen yet.  The bits might be
>> landed in libvirt/master, but there is no release with this yet and thus
>> libvirt versions using QOM for feature detection didn't find the way yet
>> into distributions.
>>
>> IMO it is a bit early to stop caring about -help output compatibility in
>> qemu.
> 
> It was announced.  There's been plenty of time to adapt.
> 
> If you're using QEMU from git, it's reasonable to require libvirt from
> git IMHO.

Agreed.

That said, distros can ease the pain by backporting the libvirt patches
for starting qemu from QMP rather than -help into current libvirt
releases, although that becomes a matter for distros rather than this list.

> 
> By the time 1.3 goes out, there should be a libvirt release with the
> necessary support so if your using distro packages, you'll never notice.

Libvirt 1.0.0 will land in early November, and fully supports qemu.git,
so you are correct that a released libvirt will be available prior to
qemu 1.3:
https://www.redhat.com/archives/libvir-list/2012-October/msg00403.html
Additionally, there will probably be a release candidate in the next 48
hours, where you can use that tarball (rawhide will most certainly pick
it up), so the pain of using libvirt.git to develop qemu.git will not
last much longer.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] qemu <-> libvirt interaction broken

[Anthony Liguori]

Eric Blake <eblake@redhat.com> writes:

> On 10/23/2012 06:47 AM, Anthony Liguori wrote:
>
>>>>
>>>> This change was postponed to after 1.2 was released to
>>>> give libvirt a chance to wean itself off parsing our --help
>>>> output.
>>>
>>> Yea, I know this has been the plan for a long time and I agree that it
>>> is a good move.
>>>
>>> Only problem is that the switch didn't happen yet.  The bits might be
>>> landed in libvirt/master, but there is no release with this yet and thus
>>> libvirt versions using QOM for feature detection didn't find the way yet
>>> into distributions.
>>>
>>> IMO it is a bit early to stop caring about -help output compatibility in
>>> qemu.
>> 
>> It was announced.  There's been plenty of time to adapt.
>> 
>> If you're using QEMU from git, it's reasonable to require libvirt from
>> git IMHO.
>
> Agreed.
>
> That said, distros can ease the pain by backporting the libvirt patches
> for starting qemu from QMP rather than -help into current libvirt
> releases, although that becomes a matter for distros rather than this list.
>
>> 
>> By the time 1.3 goes out, there should be a libvirt release with the
>> necessary support so if your using distro packages, you'll never notice.
>
> Libvirt 1.0.0 will land in early November, and fully supports qemu.git,
> so you are correct that a released libvirt will be available prior to
> qemu 1.3:
> https://www.redhat.com/archives/libvir-list/2012-October/msg00403.html
> Additionally, there will probably be a release candidate in the next 48
> hours, where you can use that tarball (rawhide will most certainly pick
> it up), so the pain of using libvirt.git to develop qemu.git will not
> last much longer.

Excellent, thanks Eric!

Regards,

Anthony Liguori

>
> -- 
> Eric Blake   eblake@redhat.com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org