Open Stack

On Wed, Feb 06, 2013 at 10:46:52AM -0500, Mark McLoughlin wrote:
> On Wed, 2013-02-06 at 15:22 +0000, Daniel P. Berrange wrote:
> > The only way we can do this is if we do *NOT* require the use of
> > classnames in config parameters. Instead we should treat all these
> > config parameters as being more like enumerations, and map those to
> > classnames internally
> > 
> > eg for the compute_driver instead of having the user set
> > 
> >   compute_driver=nova.virt.libvirt.LibvirtDriver
> > 
> > they would do
> > 
> >   compute_driver=libvirt 
> 
> I think there's already good consensus on this and the idea is to use
> entry points and stevedore to achieve it.
> 
> See:
> 
>   https://blueprints.launchpad.net/nova/+spec/entrypoints-plugins
>   https://review.openstack.org/11027
>   https://review.openstack.org/15030

Heh, I've even seen that blueprint before, but it was hard to understand
just what it was on about. A etherpad transcript of a conversation that
you weren't present for, doesn't make a nice design doc for blueprint :-(

> The end result is exactly that
> 
>   compute_driver=libvirt
> 
> will work, along with backwards compat for the original name.
> 
> It just needs to be resurrected and finished off.

Indeed, it looks like that is definitely something to have as a
priority item. Even if those patches were resurrected it looks
like quite alot more work is needed, give that they only tackle
3 out of 44+ config parameters!

Do we have any official position on config file upgrade support
at this time ?  It would be helpful to reviewers if they could
clearly identify whether a proposed config change is acceptable
or not from an upgrade POV, since currently people are holding
different changes to different standards before approval

Daniel
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