[libvirt] Ability to add arbitrary data to snapshots

[Daniel P. Berrange]

On Mon, Jan 25, 2016 at 11:54:55AM +0300, Alexander Burluka wrote:
> Just save this data near main snapshot data (e.g. in
> /var/lib/libvirt/qemu/snapshot/<domain-name>/<snapshot-hash>)
> and restore it on previous or specified path.

What sort of data is this - we already have ability to record
arbitrary metadata in the XML, so it is not particularly
attractive to add extra hacks to the snapshot XML for dealing
with extra config data, when it could be just pplaced in the
metadata block. In general I think everything we deal with
should be part of the XML config of the guest, so I don't
much like the suggestion to extend the snapshot APis to pass
through arbitrary opaque blobs.

> On 01/25/2016 11:46 AM, Daniel P. Berrange wrote:
> >On Sat, Jan 23, 2016 at 03:17:43PM +0300, Alexander Burluka wrote:
> >>Hello!
> >>
> >>Currently our Virtuozzo company is working on some kind of management tool
> >>for libvirt. We encountered some problems with snapshots while development.
> >>So I would like to ask community a few questions:
> >>1) Would you mind if I extend current libvirt snapshot with ability to add
> >>arbitrary data (blob or some config files)?
> >>2) Would this feature be useful for your users?
> >>
> >>I see it as something like:
> >>virsh snapshot-create VM1 --blob /path/to/some-file
> >>virsh snapshot-revert  VM1 <number>
> >>and /path/to/some-file appeared again.
> >You don't really explain what you would want libvirt to do with this
> >data ?

Regards,
Daniel
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