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

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

On Mon, Jan 25, 2016 at 02:55:30PM +0300, Alexander Burluka wrote: > For example, we want to store suspended state of VM. > I'm aware that some other careless application dealing with libvirt > may erase metadata section and info about additional snapshot data will be > lost. What do you mean by suspended state of the VM ? Are you referring to the VM memory & device state ? If so, I think that something that should be explicitly represented in the API, not a opaque blob.

Regards, Daniel