openstack team mailing list archive

[Gabriel Hurley <Gabriel.Hurley@xxxxxxxxxx>]

I'm normally very much in favor of stable APIs and slow deprecation, but in this case I'm far more concerned about having to support two completely independent codebases. If we pursue option 2 I think the language there needs to be even stronger and we'd have to say that nova-volume is dead/frozen, should not be touched except for release blocking bugs, shouldn't have any new bugs filed against it, etc.

Personally I'd like to follow option 1, but...

    - Gabriel

> -----Original Message-----
> From: openstack-bounces+gabriel.hurley=nebula.com@xxxxxxxxxxxxxxxxxxx
> [mailto:openstack-
> bounces+gabriel.hurley=nebula.com@xxxxxxxxxxxxxxxxxxx] On Behalf Of
> Vishvananda Ishaya
> Sent: Wednesday, July 11, 2012 8:27 AM
> To: Openstack (openstack@xxxxxxxxxxxxxxxxxxx)
> (openstack@xxxxxxxxxxxxxxxxxxx)
> Subject: [Openstack] [nova] [cinder] Nova-volume vs. Cinder in Folsom
> 
> Hello Everyone,
> 
> Now that the PPB has decided to promote Cinder to core for the Folsom
> release, we need to decide what happens to the existing Nova Volume code.
> As far as I can see it there are two basic strategies. I'm going to give an
> overview of each here:
> 
> Option 1 -- Remove Nova Volume
> ==============================
> 
> Process
> -------
>  * Remove all nova-volume code from the nova project
>  * Leave the existing nova-volume database upgrades and tables in
>    place for Folsom to allow for migration
>  * Provide a simple script in cinder to copy data from the nova
>    database to the cinder database (The schema for the tables in
>    cinder are equivalent to the current nova tables)
>  * Work with package maintainers to provide a package based upgrade
>    from nova-volume packages to cinder packages
>  * Remove the db tables immediately after Folsom
> 
> Disadvantages
> -------------
>  * Forces deployments to go through the process of migrating to cinder
>    if they want to use volumes in the Folsom release
> 
> Option 2 -- Deprecate Nova Volume
> =================================
> 
> Process
> -------
>  * Mark the nova-volume code deprecated but leave it in the project
>    for the folsom release
>  * Provide a migration path at folsom
>  * Backport bugfixes to nova-volume throughout the G-cycle
>  * Provide a second migration path at G
>  * Package maintainers can decide when to migrate to cinder
> 
> Disadvantages
> -------------
>  * Extra maintenance effort
>  * More confusion about storage in openstack
>  * More complicated upgrade paths need to be supported
> 
> Personally I think Option 1 is a much more manageable strategy because the
> volume code doesn't get a whole lot of attention. I want to keep things
> simple and clean with one deployment strategy. My opinion is that if we
> choose option 2 we will be sacrificing significant feature development in G in
> order to continue to maintain nova-volume for another release.
> 
> But we really need to know if this is going to cause major pain to existing
> deployments out there. If it causes a bad experience for deployers we need
> to take our medicine and go with option 2. Keep in mind that it shouldn't
> make any difference to end users whether cinder or nova-volume is being
> used. The current nova-client can use either one.
> 
> Vish
> 
> 
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