I've re-proposed the rbd-clone-image-handler blueprint via nova-specs: https://review.openstack.org/91486
In other news, Sebastien has helped me test the most recent incarnation of this patch series and it seems to be usable now. With an important exception of live migrations of VMs with RBD backed ephemeral drives, which will need a bit more work and a separate blueprint. On Mon, Apr 28, 2014 at 7:44 PM, Dmitry Borodaenko <dborodae...@mirantis.com> wrote: > I have decoupled the Nova rbd-ephemeral-clone branch from the > multiple-image-location patch, the result can be found at the same > location on GitHub as before: > https://github.com/angdraug/nova/tree/rbd-ephemeral-clone > > I will keep rebasing this over Nova master, I also plan to update the > rbd-clone-image-handler blueprint and publish it to nova-specs so that > the patch series could be proposed for Juno. > > Icehouse backport of this branch is here: > https://github.com/angdraug/nova/tree/rbd-ephemeral-clone-stable-icehouse > > I am not going to track every stable/icehouse commit with this branch, > instead, I will rebase it over stable release tags as they appear. > Right now it's based on tag:2014.1. > > For posterity, I'm leaving the multiple-image-location patch rebased > over current Nova master here: > https://github.com/angdraug/nova/tree/multiple-image-location > > I don't plan on maintaining multiple-image-location, just leaving it > out there to save some rebasing effort for whoever decides to pick it > up. > > -DmitryB > > On Fri, Mar 21, 2014 at 1:12 PM, Josh Durgin <josh.dur...@inktank.com> wrote: >> On 03/20/2014 07:03 PM, Dmitry Borodaenko wrote: >>> >>> On Thu, Mar 20, 2014 at 3:43 PM, Josh Durgin <josh.dur...@inktank.com> >>> wrote: >>>> >>>> On 03/20/2014 02:07 PM, Dmitry Borodaenko wrote: >>>>> >>>>> The patch series that implemented clone operation for RBD backed >>>>> ephemeral volumes in Nova did not make it into Icehouse. We have tried >>>>> our best to help it land, but it was ultimately rejected. Furthermore, >>>>> an additional requirement was imposed to make this patch series >>>>> dependent on full support of Glance API v2 across Nova (due to its >>>>> dependency on direct_url that was introduced in v2). >>>>> >>>>> You can find the most recent discussion of this patch series in the >>>>> FFE (feature freeze exception) thread on openstack-dev ML: >>>>> >>>>> http://lists.openstack.org/pipermail/openstack-dev/2014-March/029127.html >>>>> >>>>> As I explained in that thread, I believe this feature is essential for >>>>> using Ceph as a storage backend for Nova, so I'm going to try and keep >>>>> it alive outside of OpenStack mainline until it is allowed to land. >>>>> >>>>> I have created rbd-ephemeral-clone branch in my nova repo fork on >>>>> GitHub: >>>>> https://github.com/angdraug/nova/tree/rbd-ephemeral-clone >>>>> >>>>> I will keep it rebased over nova master, and will create an >>>>> rbd-ephemeral-clone-stable-icehouse to track the same patch series >>>>> over nova stable/icehouse once it's branched. I also plan to make sure >>>>> that this patch series is included in Mirantis OpenStack 5.0 which >>>>> will be based on Icehouse. >>>>> >>>>> If you're interested in this feature, please review and test. Bug >>>>> reports and patches are welcome, as long as their scope is limited to >>>>> this patch series and is not applicable for mainline OpenStack. >>>> >>>> >>>> Thanks for taking this on Dmitry! Having rebased those patches many >>>> times during icehouse, I can tell you it's often not trivial. >>> >>> >>> Indeed, I get conflicts every day lately, even in the current >>> bugfixing stage of the OpenStack release cycle. I have a feeling it >>> will not get easier when Icehouse is out and Juno is in full swing. >>> >>>> Do you think the imagehandler-based approach is best for Juno? I'm >>>> leaning towards the older way [1] for simplicity of review, and to >>>> avoid using glance's v2 api by default. >>>> [1] https://review.openstack.org/#/c/46879/ >>> >>> >>> Excellent question, I have thought long and hard about this. In >>> retrospect, requiring this change to depend on the imagehandler patch >>> back in December 2013 proven to have been a poor decision. >>> Unfortunately, now that it's done, porting your original patch from >>> Havana to Icehouse is more work than keeping the new patch series up >>> to date with Icehouse, at least short term. Especially if we decide to >>> keep the rbd_utils refactoring, which I've grown to like. >>> >>> As far as I understand, your original code made use of the same v2 api >>> call even before it was rebased over imagehandler patch: >>> >>> https://github.com/jdurgin/nova/blob/8e4594123b65ddf47e682876373bca6171f4a6f5/nova/image/glance.py#L304 >>> >>> If I read this right, imagehandler doesn't create the dependency on v2 >>> api, the only reason it caused a problem was because it exposed the >>> output of the same Glance API call to a code path that assumed a v1 >>> data structure. If so, decoupling rbd clone patch from imagehandler >>> will not help lift the full Glance API v2 support requirement, that v2 >>> api call will still be there. >>> >>> Also, there's always a chance that imagehandler lands in Juno. If it >>> does, we'd be forced to dust off the imagehandler based patch series >>> again, and the effort spent on maintaining the old patch would be >>> wasted. >>> >>> Given all that, and without making any assumptions about stability of >>> the imagehandler patch in its current state, I'm leaning towards >>> keeping it. If you think it's likely that it will cause us more >>> problems than the Glance API v2 issue, or if you disagree with my >>> analysis of that issue, please tell. >> >> >> My impression was that full glance v2 support was more of an issue >> with the imagehandler approach because it's used by default there, >> while the earlier approach only uses glance v2 when rbd is enabled. >> >> >>>> I doubt that full support for >>>> v2 will land very fast in nova, although I'd be happy to be proven wrong. >>> >>> >>> I'm sceptical about this, too. That's why right now my first priority >>> is making sure this patch is usable and stable with Icehouse. >>> Post-Icehouse, we'll have to see where glance v2 support in nova goes, >>> if anywhere at all. Not much point making plans when we can't even >>> tell if we'll have to rewrite this patch yet again for Juno. >> >> >> Sounds good. We can discuss more with nova folks once Juno opens, >> since we'll need to go through the new blueprint approval process >> anyway. >> >> Josh > > > > -- > Dmitry Borodaenko -- Dmitry Borodaenko _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
