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On 09/04, Sean McGinnis wrote:
> On Mon, Apr 09, 2018 at 07:00:56PM +0100, Duncan Thomas wrote:
> > Hopefully this flow means we can do rebuild root filesystem from
> > snapshot/backup too? It seems rather artificially limiting to only do
> > restore-from-image. I'd expect restore-from-snap to be a more common
> > use case, personally.
> >
>
> That could get tricky. We only support reverting to the last snapshot if we
> reuse the same volume. Otherwise, we can create volume from snapshot, but I
> don't think it's often that the first thing a user does is create a snapshot on
> initial creation of a boot image. If it was created from image cache, and the
> backend creates those cached volume by using a snapshot, then that might be an
> option.
>
> But these are a lot of ifs, so that seems like it would make the logic for this
> much more complicated.
>
> Maybe a phase II optimization we can look into?
>

>From the Cinder side of things I think these two would be easier than
the re-image, because we would have even fewer steps, and the
functionality to do the copying is exactly what we have now, as it will
copy the data to the same volume, so we wouldn't need to fiddle with the
UUID fields etc.

Moreover I know customers who have asked about this functionality in the
past, mostly interested in restoring the root volume of an existing VM
from a backup to preserve the system ID and not break licenses.