Re: [libvirt-users] [RFC] per-device metadata

For techincal discussions on design it's better to post to the development list. On Mon, Feb 27, 2017 at 16:41:28 +0100, Francesco Romani wrote: > Hi, Hi, > > > Currently libvirt supports metadata in the domain XML. This is very > convenient for data related to the VM, but it is a little awkward for > devices. Let's pretend I want to have extradata (say, a specific port > for a virtual switch) related to a device (say, a NIC). Nowadays I can > store that data in the metadata section, but I need some kind of mapping > to correlate this piece of information to the specific device. > > I can use the device alias, but this is not available when the device is > created. This is also more complex when doing hotplug/hotunplug, because > I need to do update device and update metadata; if either fails, the > entire operation must be considered failed. > > It would be nice to be able to attach metadata to the device, and this > is what I'm asking for/proposing in this mail. > > Would it be possible in a future libvirt release? In general I don't have a problem with this and if it would make the life of mgmt tools easier I don't see a reason why not. There's one problem though. For setter (or getter) APIs for the metadata you need a way how to uniquely identify a device on which you want to operate. There's no such way currently in use in libvirt so you need to come up with something to do it.