[openstack-dev] [Nova] [RBD] Copy-on-write cloning for RBD-backed disks

Dmitry Borodaenko dborodaenko at mirantis.com
Wed Jul 16 21:17:57 UTC 2014


I've got a bit of good news and bad news about the state of landing
the rbd-ephemeral-clone patch series for Nova in Juno.

The good news is that the first patch in the series
(https://review.openstack.org/91722 fixing a data loss inducing bug
with live migrations of instances with RBD backed ephemeral drives)
was merged yesterday.

The bad news is that after 2 months of sitting in review queue and
only getting its first a +1 from a core reviewer on the spec approval
freeze day, the spec for the blueprint rbd-clone-image-handler
(https://review.openstack.org/91486) wasn't approved in time. Because
of that, today the blueprint was rejected along with the rest of the
commits in the series, even though the code itself was reviewed and
approved a number of times.

Our last chance to avoid putting this work on hold for yet another
OpenStack release cycle is to petition for a spec freeze exception in
the next Nova team meeting:
https://wiki.openstack.org/wiki/Meetings/Nova

If you're using Ceph RBD as backend for ephemeral disks in Nova and
are interested this patch series, please speak up. Since the biggest
concern raised about this spec so far has been lack of CI coverage,
please let us know if you're already using this patch series with
Juno, Icehouse, or Havana.

I've put together an etherpad with a summary of where things are with
this patch series and how we got here:
https://etherpad.openstack.org/p/nova-ephemeral-rbd-clone-status

Previous thread about this patch series on ceph-users ML:
http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-March/028097.html

-- 
Dmitry Borodaenko



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