openstack team mailing list archive

[Brian Waldon <brian.waldon@xxxxxxxxxxxxx>]

tl;dr: I vote for option 2 as it's the only reasonable path from a deployer's point of view

With my deployer hat on, I think option 1 isn't really valid. It's completely unfair to force deployers to use Cinder before they can upgrade to Folsom. There are real deployments using nova-volumes, let's not screw them.

With my developer hat on, I don't want to support two forks of the same slowly-diverging codebase. I definitely want to make sure our stuff is consumable, but we can't be expected to support everything forever. How about we leave nova-volumes in for the Grizzly release, but with a deprecation warning and a notice that we will only maintain it as we would a stable release branch (no features).

Waldon


On Jul 11, 2012, at 8:26 AM, Vishvananda Ishaya wrote:

> 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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