Open Stack

On 04/16/2015 12:26 AM, Matt Fischer wrote:
> Recently a mass of changes was proposed and some merged to move the
> rabbit/kombu settings to avoid a Kilo deprecation. As far as I can tell
> this will break rabbit connectivity for all modules still using Juno. I
> did an experiment with Heat and it certainly can't talk to rabbit
> anymore. (Hopefully you guys can just tell me I'm wrong here and
> everything will still work)
> 
> So why did we do this? We seem to have traded a slightly annoying
> deprecation warning for breaking every single module. It does not seem
> like a good trade-off to me. At a minimum, I would have liked to wait
> until we had forked Kilo off and we're working towards Liberty. Why?
> Because there was simply no pressing reason to do this right now when
> most everyone is still using Juno.
> 
> Since we as a community are pretty terrible at backports, this means
> that I now need to switch to stable and sit on old and non-updated code
> until I can upgrade to Kilo, which is likely a minimum of 45 days away
> for many components for us.

We do our best now to backport what is backportable to stable/juno.

> This has implications for my team beyond breaking everything:
> 
> * It means that we need to stop importing puppet code changes with our
> git-upstream jobs. This makes the process of moving back to master when
> we finally can quite painful. I had to do it for Icehouse and I don't
> relish doing it again.
> 
> * It means that any fixes we want will require a two step process to get
> into backports. This delays things obviously.
> 
> * It means that the number of contributions you will get from us will
> probably fall, not being on master makes it way more likely for us just
> to hold patches.
> 
> * It means that we will have to write a shim layer in our module to deal
> with these settings and whatever else gets broken like this.
> 
> So I'd like to discuss the philosophy of why this was done. I'd also
> again like to put in my vote for master supporting current-1 for at
> least some period of time. There's a reason that the upstream code that
> we configure just did this with a deprecation rather than a "if you set
> it like this you are broken". We should do the same.

FWIW, even without rabbit/kombu topic, master won't work on Juno, there
is plenty of things that are brought in Kilo.

My opinion is we should follow other projects that use stable branches
with doing deprecation for one (or more?) release (currently our master)
and then drop the deprecations after some time.

So I would propose this policy:
* for new features, patch master with backward compatibility
* backports relevant patches from master to stable branches (mainly bugs)
* in the case of rabbit or any update in OpenStack upstream, update
master without backward compatibility, except if we accept to have a lot
of if/else in our code, and a lot of backwards to support; I'm not in
favor of that.

> For now I've -1'd all the outstanding reviews until we can have a
> discussion about it. I know one was merged despite my -1, but I didn't
> think a -2 was warranted.
> 

It's on the agenda for Tuesday's meeting (thanks Matt for this).
In the meantime, any feedback is welcome,

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-- 
Emilien Macchi

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