[openstack-dev] [requirements] History lesson please

Chris Friesen chris.friesen at windriver.com
Wed Aug 10 16:48:25 UTC 2016

On 08/10/2016 04:51 AM, Erno Kuvaja wrote:
> On Wed, Aug 10, 2016 at 9:27 AM, Thomas Goirand <zigo at debian.org> wrote:

>> Not necessarily. Take for example Swift. It has lower requirements than
>> other projects in OpenStack. Yet, Swift is fully co-installable with all
>> other OpenStack projects. They just support lower versions than others.
> This just makes lifecycle management total nightmare if different
> project has different requirements within same release. Lets say we
> have these projects Swift, X and Y that supports the lower versions,
> now we decide to deploy Z to that same cloud but Z has higher
> requirement than Swift, X and Y, so we need to upgrade that
> requirement at minimum to that new level required by Z.
> Having 3 options here:
> 1) We upgrade the requirement to the new level system wide and restart
> Swift, X and Y to avoid any nasty surprises later down the line, which
> is risky and disruptive by itself.
> 2) We containerize/use venv for Z and provide the new version of the
> dependency just for that.
> 3) We deploy Z to it's own node.

As Doug Hellman said earlier in the thread, they recommend to deployers/packages 
that they use the *highest* supported version as listed in upper-constraints.txt.

In the case above, if the deployer had done this then bringing in Z would likely 
not have resulted in a need to upgrade any requirements.


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