Open Stack

On 09/28/2015 10:29 AM, Ben Swartzlander wrote:
> I've always thought it was a bit strange to require new drivers to 
> merge by milestone 1. I think I understand the motivations of the 
> policy. The main motivation was to free up reviewers to review "other 
> things" and this policy guarantees that for 75% of the release 
> reviewers don't have to review new drivers. The other motivation was 
> to prevent vendors from turning up at the last minute with crappy 
> drivers that needed a ton of work, by encouraging them to get started 
> earlier, or forcing them to wait until the next cycle.
>
> I believe that the deadline actually does more harm than good.
But harm to whom?   It certainly puts the pressure on driver developers 
to make sure they get involved in the Cinder community and get aware of 
when the deadlines are.
I believe it simply shifts the time in which drivers get into tree. My 
$0.02 of opinion is, that if a new driver developer misses the 
milestone, then they have the rest of the release to work on getting CI 
up and running and ready to go for the next release.   I'm not sure I 
see the harm to the Cinder community or the project.   It's a deadline 
that a driver developer has to be aware of and compensate for.  We've 
had how many drivers land in the last 2 releases using this 
requirement?  I believe it's somewhere of 20+ drivers?

>
> First of all, to those that don't want to spend time on driver 
> reviews, there are other solutions to that problem. Some people do 
> want to review the drivers, and those who don't can simply ignore them 
> and spend time on what they care about. I've heard people who spend 
> time on driver reviews say that the milestone-1 deadline doesn't mean 
> they spend less time reviewing drivers overall, it just all gets 
> crammed into the beginning of each release. It should be obvious that 
> setting a deadline doesn't actually affect the amount of reviewer 
> effort, it just concentrates that effort.
>
> The argument about crappy code is also a lot weaker now that there are 
> CI requirements which force vendors to spend much more time up front 
> and clear a much higher quality bar before the driver is even 
> considered for merging. Drivers that aren't ready for merge can always 
> be deferred to a later release, but it seems weird to defer drivers 
> that are high quality just because they're submitted during milestones 
> 2 or 3.
I disagree here.  CI doesn't prevent you from having a crappy driver.  
Your driver just needs to pass CI tests.  CI ensures that your driver 
works, but doesn't ensure that it
really meats the core reviewers standards for code.  Do we care?  I 
think we do.  Having drivers talk directly to the db, or FC drivers 
missing the FCZM decorators for auto zoning, etc.

>
> All the the above is just my opinion though, and you shouldn't care 
> about my opinions, as I don't do much coding and reviewing in Cinder. 
> There is a real reason I'm writing this email...
>
> In Manila we added some major new features during Liberty. All of the 
> new features merged in the last week of L-3. It was a nightmare of 
> merge conflicts and angry core reviewers, and many contributors worked 
> through a holiday weekend to bring the release together. While asking 
> myself how we can avoid such a situation in the future, it became 
> clear to me that bigger features need to merge earlier -- the earlier 
> the better.
>
> When I look at the release timeline, and ask myself when is the best 
> time to merge new major features, and when is the best time to merge 
> new drivers, it seems obvious that *features* need to happen early and 
> drivers should come *later*. New major features require FAR more 
> review time than new drivers, and they require testing, and even after 
> they merge they cause merge conflicts that everyone else has to deal 
> with. Better that that works happens in milestones 1 and 2 than right 
> before feature freeze. New drivers can come in right before feature 
> freeze as far as I'm concerned. Drivers don't cause merge conflicts, 
> and drivers don't need huge amounts of testing (presumably the CI 
> system ensure some level of quality).
>
> It also occurs to me that new features which require driver 
> implementation (hello replication!) *really* should go in during the 
> first milestone so that drivers have time to implement the feature 
> during the same release.
>
> So I'm asking the Cinder core team to reconsider the milestone-1 
> deadline for drivers, and to change it to a deadline for new major 
> features (in milestone-1 or milestone-2), and to allow drivers to 
> merge whenever*. This is the same pitch I'll be making to the Manila 
> core team. I've been considering this idea for a few weeks now but I 
> wanted to wait until after PTL elections to suggest it here.
>
> -Ben Swartzlander
>
>
> * I don't actually care if/when there is a driver deadline, what I 
> care about is that reviewers are free during M-1 to work on 
> reviewing/testing of features. The easiest way to achieve that seems 
> to be moving the driver deadline.
I'm not opposed to M-2 for new drivers, but I think it simply shifts the 
headache of 3000+ line driver reviews to M-2 instead of M-1, reviewers 
will spend their time reviewing core features and not look at drivers 
until the M-2 deadline.  Is that better or worse?  I think part of this 
is why we've raised the discussion of pulling drivers out of Cinder tree.
I'm not clear how that helps the community and quality of drivers though.

Walt