Open Stack

Hi Rob,

I think it looks like a good option -  but I'd like to see it exposed as such to the user rather than a change in the default behavior as such.  I.e. "rebuild --keep-ephemenral=True ...."

Phil


> -----Original Message-----
> From: Robert Collins [mailto:robertc at robertcollins.net]
> Sent: 28 October 2013 02:00
> To: OpenStack Development Mailing List; Russell Bryant; Joe Gordon
> Subject: [openstack-dev] [Nova] Preserving ephemeral block device on
> rebuild?
> 
> For context, in TripleO we have precious state to preserve when we push
> updates out to a cluster: nova instance volumes (obviously), swift data
> stores, mysql db's etc. We have a long term plan to have a volume model and
> interface that with Cinder, but thats an Ironic planed feature, and somewhat
> down the track : in the short term we'd like to use the ephemeral volume for
> such storage: it seems like 'nova rebuild' could easily be extended to
> preserve the ephemeral block device.
> 
> From a nova bm perspective, all that needs to happen is for us to /not/
> format the volume - simples - and we can do that in the current rebuild code
> path where destroy + spawn is called, as long as we end up on the same
> host.
> 
> However, we'd like to support this for libvirt too, because that lets us test
> workflows in virt rather than on purely baremetal (or emulated baremetal).
> For that, it looks to me like we need to push rebuild down a layer to the virt
> driver : so rather than destroy(); spawn(); have a
> rebuild() method that takes the same data spawn would, and will be able to
> preserve data as needed.
> 
> Seeking thoughts on this - both the use of ephemeral in this way, and
> sketched out code change - are sought!
> 
> Thanks,
> Rob
> 
> --
> Robert Collins <rbtcollins at hp.com>
> Distinguished Technologist
> HP Converged Cloud
> 
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev