libvirt version supporting revert external snapshot

Bug #1710251 reported by Thierry Bouhnik on 2017-08-11
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
libvirt (Ubuntu)
Wishlist
Unassigned

Bug Description

Hello,

I read that libvirt used by ubuntu didn't support revert from external snapshot.

Do you know from which version of libvrt it's fully supported?

And otherwise, is it previous to integrate in the version ubuntu I used or maybe if I use a backport package?

I use Ubuntu 16.04.2 LTS and my versions of libvirt packages :

root@D54250WYK:/home/thierry# dpkg -l | grep "libvirt"
ii gir1.2-libvirt-glib-1.0:amd64 0.2.2-0.1ubuntu1 amd64 libvirt glib mainloop integration
ii libvirt-bin 1.3.1-1ubuntu10.10 amd64 programs for the libvirt library
ii libvirt-glib-1.0-0:amd64 0.2.2-0.1ubuntu1 amd64 libvirt glib mainloop integration
ii libvirt0:amd64 1.3.1-1ubuntu10.10 amd64 library for interfacing with different virtualization systems
ii python-libvirt 1.3.1-1ubuntu1 amd64 libvirt Python bindings

# libvirtd --version
libvirtd (libvirt) 1.3.1

# virsh --version
1.3.1

Thanks.

ChristianEhrhardt (paelzer) wrote :

Hi Thierry,

I don't know of any Ubuntu specific lack of support, please let me know if there is.
What I know about that - and furthermore for the benefit of everybody else getting - can be found at [1]. That page is a nice summary on the topic. Related to that also are the use-cases from [2]. They might be slightly outdated, I think I saw a new format being ,snapshot=external.

TL;DR
- internal snapshots are within qcow2 - fully supported in libvirt
- external snapshots (qemu backing chains) are in favor qemu
- libvirt doesn't fully support all operations on external snapshot

I didn't track this area in particular but didn't see it show up as a new major item (and IMHO it would be one). On one hand the changelog never held it as major feature in recent years, on the other hand the wording of (internal) snapshot != (external) snapshot in libvirt makes it harder to search for it.

Thereby I think it isn't "fully supported" in any version of libvirt yet other than with the workarounds and use-cases described on [1][2] that worked already with the libvirt that was released with Xenial.

Now if such a feature would be developed upstream (or if I missed that it already is but under a different name) your general question gets more important. In understood it as "how to get a newer but supported virtualization stack while still staying at the LTS release", to do so I'd recommend you take a look at [3].

Unless I misunderstood you (I beg your pardon in that case and ask you to explain) I think this is a upstream feature request and therefore I classify the bug as that for now.

[1]: https://wiki.libvirt.org/page/I_created_an_external_snapshot,_but_libvirt_will_not_let_me_delete_or_revert_to_it
[2]: http://wiki.libvirt.org/page/Live-disk-backup-with-active-blockcommit
[3]: https://wiki.ubuntu.com/OpenStack/CloudArchive

Changed in libvirt (Ubuntu):
importance: Undecided → Wishlist
status: New → Opinion
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