Open Stack

Hello,

I have 2 use cases, asked by my users :
Be able to take a snapshot, and then :
1) be able to revert back an instance to the snapshot (conserving name 
and IP addresses)
2 create new instances from the snapshot

The second one is the standard way of doing snapshots in OpenStack 
(Nova).
For the first one, I found that nova rebuild is doing fine.

But. All this is working with standard snapshots, which create images. 
It can be quite long. I also have a VMware region, and here, it's really 
long to transfer between glance and nova.

So I tried to use volume (Cinder) backed instances.

If the storage supports COW or linked clones, it's fast.
But. Rebuild is not doing what we want (it does nothing in fact) :
http://lists.openstack.org/pipermail/openstack-dev/2015-July/068493.html

Other problem : with VMware, snapshot of volumes is not possible if the 
volume is in the state 'in-use' (even if the VM is powered off).
There's a bug, the snapshot is created in error state, and it's really 
difficult to delete it : must change the state of the parent volume and 
the snapshot to available. And for that, you need to be admin.

So, if someone manage to find a good way to handle fast snapshots, and 
be able to revert an instance back, please share !

I use Kilo (prod) and Liberty (test), GlusterFS as storage for my KVM 
region, VMware for a second region.

--
GillesMo