Re: [libvirt-users] Device lease hot unplug and events

On Mon, Oct 15, 2018 at 09:56:39 +0200, Milan Zamazal wrote: > Peter Krempa <pkrempa(a)redhat.com&gt; writes: > > > On Fri, Oct 12, 2018 at 19:33:54 +0200, Milan Zamazal wrote: > >> Hi, when working on hot unplugs of various devices, I've found out that > >> hot unplugging <lease> device doesn't generate > >> VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED event. <lease> also doesn't have an > >> alias, so it wouldn't be identifiable in the corresponding callback. > >> > >> Is this difference from other hotpluggable devices intentional? If yes, > > > > Well a "lease" is not a device per-se. It's just libvirt putting it with > > devices. Currently the "lease" is always successfully removed/unplugged > > if the API returns success as there is no cooperation with qemu > > necessary so the semantics of asking the guest OS to do something don't > > apply. > > I see, thank you for explanation. Can we rely on the fact that lease > removal is and remains synchronous or is it a property that can change > in the future? In case of the current implementation I don't see a reason why we'd have to change it. If so it would be for a different "model". Generally we can't guarantee that some usage will not eventually need it but we should not change this behaviour, or at least I don't expect us to. > > >> is there any better way of checking that <lease> removal is completed > >> than querying and examining the domain XML? From user's point of view, > >> it would be best if I could simply handle the device removal event the > >> same way as with other devices. > > > > Yes, we probably should add the event and synthetize it for "lease" > > since we will not get one from qemu. Also we'll need to add alias for > > the lease so that the event can be used. > > Since this is what an uninformed user expects (and I believe libvirt > documentation doesn't contradict), I'd like to have the event + alias. > Should I file a corresponding bug or RFE? Yes please.