Open Stack

On 19:53 Aug 19, John Griffith wrote:
> On Wed, Aug 19, 2015 at 7:48 PM, <Taylor.Bertie at solnet.co.nz> wrote:
> 
> > Hi everyone,
> >
> > Apologises for the duplicate send, looks like my mail client doesn't
> > create very clean HTML messages. Here is the message in plain-text. I'll
> > make sure to send to the list in plain-text from now on.
> >
> > In my current pre-production deployment we were looking for a method to
> > live extend attached volumes to an instance. This was one of the
> > requirements for deployment. I've worked with libvirt hypervisors before so
> > it didn't take long to find a workable solution. However I'm not sure how
> > transferable this will be across deployment models. Our deployment model is
> > using libvirt for nova and ceph for backend storage. This means obviously
> > libvirt is using rdb to connect to volumes.

<snip>
 
> ​Hey Taylor,
> 
> This is something that has come up a number of times but I personally
> didn't have a good solution for it on the iSCSI side.  I'm not sure if your
> method would work with iSCSI attached devices because typically you need to
> detach/reattach for size changes to take effect, in other words I'm
> uncertain if libvirt would be able to see the changes.  That being said I
> also didn't know about this option in libvirt so it may work out.

This was discussed at the last Cinder midcycle meetup [1]. I'm not really
involved with working out the solution here, but the people involved we're
saying that there is a solution of having the shared library between Cinder and
Nova os-brick having the ability to inform libvirt of the size change.

The only caveat that we need Nova to agree on is this would only work with
Libvirt. This is planned for the M release.

[1] - https://etherpad.openstack.org/p/cinder-meetup-summer-2015

-- 
Mike Perez