9:09 a.m.
On Tue, Aug 23, 2022 at 12:10:14PM +0100, Daniel P. Berrangé wrote:
On Tue, Aug 23, 2022 at 01:01:49PM +0200, Martin Kletzander wrote:
> On Tue, Aug 23, 2022 at 11:39:10AM +0100, Daniel P. Berrangé wrote:
> > On Thu, Aug 04, 2022 at 03:07:17PM +0200, Martin Kletzander wrote:
> > > Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
> > > ---
> > > docs/formatdomain.rst | 24 ++++++++++++++++++++++++
> > > src/ch/ch_monitor.c | 1 +
> > > src/conf/domain_conf.c | 10 ++++++++++
> > > src/conf/domain_conf.h | 1 +
> > > src/conf/netdev_bandwidth_conf.c | 1 +
> > > src/conf/schemas/domaincommon.rng | 7 +++++++
> > > src/libxl/libxl_conf.c | 1 +
> > > src/libxl/xen_common.c | 1 +
> > > src/lxc/lxc_controller.c | 1 +
> > > src/lxc/lxc_driver.c | 3 +++
> > > src/lxc/lxc_process.c | 4 +++-
> > > src/qemu/qemu_command.c | 4 ++++
> > > src/qemu/qemu_domain.c | 1 +
> > > src/qemu/qemu_hotplug.c | 3 +++
> > > src/qemu/qemu_interface.c | 2 ++
> > > src/qemu/qemu_process.c | 2 ++
> > > src/qemu/qemu_validate.c | 1 +
> > > src/vmx/vmx.c | 1 +
> > > tools/virsh-domain.c | 1 +
> > > 19 files changed, 68 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> > > index adfdd7b7a5ac..ed0d9c19593b 100644
> > > --- a/docs/formatdomain.rst
> > > +++ b/docs/formatdomain.rst
> > > @@ -5240,6 +5240,30 @@ which the UDP socket packets will originate from the
QEMU host. :since:`Since
> > > </devices>
> > > ...
> > >
> > > +Dummy network interface
> > > +^^^^^^^^^^^^^^^^^^^^^^^
> > > +
> > > +An unconnected network interface sounds pretty pointless, but can show up
for
> > > +example with VMWare when libvirt does not have any more information to
provide.
> > > +Two such scenarios are currently known:
> > > +
> > > +1) network interface exists, but is not connected to any existing network
> > > +2) the interface is connected to something known as VMWare Distributed
Switch
> > > +
> > > +The difference between these two is not (yet?) discoverable by libvirt, so
at
> > > +least the information gathered from the hypervisor is provided in the
> > > +element. :since:`Since 8.7.0`
> > > +
> > > +::
> > > +
> > > + ...
> > > + <devices>
> > > + <interface type='dummy'>
> > > + <mac address='52:54:00:22:c9:42'/>
> > > + </interface>
> > > + </devices>
> > > + ...
> >
> > Calling this 'dummy' is not very desirable naming. Especially since
> > the distributed switch config is handled separately, we're just left
> > with the case of a network interface without any host backend.
> >
>
> I'll gladly rename this, I don't like dummy neither, but the only thing
> I can think of is "unconnected". At first I went with existing
type=direct,
> but without <target dev=/>, only with <target managed='no'/>, but
that
> did not really make sense in my opinion.
>
> > IMHO this should just be type="none", and would likely be viable for
> > QEMU too.
> >
>
> Unfortunately type="none" usually (in our XML) means there is none of
> this type of device (usb, memballoon, etc.), so I don't think that would
> make sense compared to rest of our XML.
Hmm, yes, good point. Some other ideas including yours..
type='unconnected'
type='disconnected'
type='unplugged'
These seem to collide with <link state='down'/>, even though it really
is what VMWare seems to do on the NIC as well, just that you cannot
"plug" it anywhere.
type='null' (as in /dev/null alike)
but together with this they are all better than "dummy", I agree. Any
preference before I send a rename patch?
> I also thought about having this in QEMU, but given how pointless this
> configuration is (and we just want to be able to express such
> configuration so that virt-v2v can convert such domains) I am not sure
> whether there's a point to adding this support to QEMU. And looking at
> the possibilities of what could be done on QEMU cmdline (without
> modifying QEMU), we would have to create a network device which is not
> connected anywhere, but QEMU does not support this, so the only way I
> found out was adding a hubport that's not connected anywhere, something
> like:
>
> -netdev hubport,id=test0,hubid=0 -device e1000e,netdev=test0
>
> which emits a warning during startup:
>
> qemu-system-x86_64: warning: hub 0 is not connected to host network
>
> but as mentioned before, I think that's pointless to try to support it.
You don't need a hub, it is fine to just have '-device e1000e' with
no netdev property, but yes, that too generates a warning
qemu-system-x86_64: warning: nic e1000e.0 has no peer
The warning is trying to be helpful to detect mistakes of course,
but if someone genuinely wants a disconnected NIC it is annoying.
Anyway, there's no pressing need to implement QEMU support today,
I just wanted to point out it is relevant to more than just vmware.
Sure, it might be, and anyone can implement it later on, that's why I
only used the VMWare scenario as an "example".
> Let me know what you think, I'm fine with any changes if it
supports the
> now "fixed" scenario, but naming should better be fixed before a
> release.
With regards,
Daniel
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