[openstack-dev] [puppet] [fuel] more collaboration request

Zane Bitter zbitter at redhat.com
Fri Jun 12 21:26:11 UTC 2015

This thread kind of deteriorated a bit (though it looks like it's 
hopefully recovering), so I'd just like to add some observations.

What we have here is a classic case of a long-running fork, with all 
that that entails. In this case the fork is a public one, but that 
actually makes very little difference to the fundamentals. (I think it's 
great that Mirantis have chosen to develop Fuel in the open though! Kudos.)

The fact is that maintaining a fork is very expensive. And while it's 
expensive for the upstream community in terms of lost opportunities for 
bug fixes, it's far, far more expensive for the maintainers of the 
downstream fork. IMHO that's one of the reasons that permissive licenses 
like ASL2 have gained so much ground over the GPL - it didn't take very 
long for almost everyone to realise that there were more compelling 
reasons to contribute your code upstream than that you were compelled to 
by the license. I don't think a project like OpenStack could exist if 
they hadn't. It's simply better business, even if you consider the other 
upstream users to be competitors.

So I think both projects would benefit from more co-operation, but Fuel 
has by far the most to gain.

I see from the thread that a lot of well-intentioned policies have been 
put in place to try to improve co-operation, and it's actually not that 
surprising to see them not working that well because the incentives are 
wrong. When you set up a conflict between incentives and rules... 
incentives tend to win. (I probably don't need to try to prove this, 
because it was IMHO one of the great lessons of the communist 
experiment, and looking at the names in this thread I suspect that most 
of y'all at least know someone with direct experience of that.)

So at the moment committing a patch to Fuel is easy for a Fuel 
developer, whereas getting that same patch into upstream is hard. So it 
is much more likely that the downstream patch lands while the upstream 
patch languishes, despite the hidden cost that another Fuel developer 
will need to reconcile the two later. To get this to work, you need to 
make upstream the default (and therefore easiest) path to get changes 
included in Fuel.

Of course you will need a way to make urgent changes to your product 
without waiting for upstream. As an example, we do this in RDO Manager 
by maintaining patches on top of an upstream snapshot. (We do actually 
use Git - in a non-traditional way - as a tool to aid this process, but 
it's not really the point and there are many ways to tackle the 
problem.) The snapshot gets updated regularly, so changes that are 
committed upstream just show up without any extra work. If we need 
something urgently, we have to option to apply it as a patch, but our 
enthusiasm to do so is always tempered by the knowledge that if a change 
that is at least extremely similar does not land upstream then we are 
creating extra work for ourselves in the very near future. That's how we 
keep the incentives and policies aligned. (In this way, building a 
project around a library like this is very similar to building a 
downstream distribution around an upstream project. We use essentially 
the same techniques.)

And of course once the upstream becomes the default place to land 
patches, you'll very quickly stop thinking of upstream as 'them' and 
start thinking of them as 'us'. You'll start assimilating the ideas of 
what are and are not good coding standards so that you won't have to 
rework them nearly as much before they can be merged, and once you get 
involved in the community you'll have the opportunity to influence those 
ideas as well. Once everyone is up to speed I'm sure you'd see a lot of 
folks get added to core. Instead of upstream co-operation appearing to 
consume time that you don't have (which appears to be the problem at the 
moment), I'm quite sure that same people will be able to get a *lot* 
more done.

Tinkering with the current model by putting in place more policies or 
trying to offload work to the upstream openstack-puppet team will not 
work, and more importantly would not realise the same benefits to the 
Fuel team even if it did work.

The problem, of course, is that once you are on a long-running fork it 
takes a big up-front investment to get off it. (Ask anyone still running 
an OpenStack Folsom cloud ;) That can be hard to make a case for, 
especially when you have other priorities and the dividends take some 
time to appear. I think in this case it would be totally worth the 
investment, and I hope the Fuel team will consider making that investment.

As a bonus, it'll be more polite to the original authors of the code, 
it'll help everyone who is deploying OpenStack with Puppet (which is 
most people in the community), and it'll help Fuel users join a bigger 
critical mass of users so they can get better support from channels like 


On 11/06/15 10:36, Matthew Mosesohn wrote:
> Hi Emilien,
> I can see why you might be unhappy with Fuel's actions with regards to
> the OpenStack Puppet modules. You could make this argument about many
> components in Fuel. The heart of the matter is that we bundle the
> upstream OpenStack Puppet modules with all the other modules,
> developed both upstream and by Fuel's developers in one single git
> repository. This decision, along with all the other decisions to put
> Fuel's components under its own repositories, was intended to add
> stability and granular control to the product. I'm not saying it's the
> most community-oriented approach, but Fuel would have never evolved
> and matured without it. The attribution in commits is lost because our
> directory namespace differs such that it can't just be merged cleanly.
> Revisiting submodules is an option, but it led to maintenance problems
> in the past.
> Secondly, I'd like to point out that Fuel is not so different from
> what other teams are doing. At the Summit, I heard from others who all
> maintain internal Gerrits and internal forks of the modules. The
> difference is that Fuel is being worked on in the open in StackForge.
> Anyone is free to contribute to Fuel as he or she wishes, take our
> patches, or review changesets.
> Starting in October 2014, the Fuel team has adopted a policy that we
> cannot merge any patches into the core Puppet OpenStack modules of
> Fuel without submitting a patch or at least a bug upstream. Our
> reviewers block patches consistently. The truth is that the upstream
> modules are quite excellent and we don't need to make changes so
> often. Our goal is to work with upstream modules or in the issue where
> upstream integration is impossible, we place that config in our own
> separate modules.
> The point you raised about fixing bugs in Fuel and not in Puppet
> OpenStack is definitely valid and something we need to collaborate on.
> The first and easiest option when a bug is applicable to both, we
> could use Launchpad to assign bugs to both Fuel project and
> puppet-$project so it gains visibility. If a bug is discovered in
> Puppet OpenStack after it's been reported and/or fixed in Fuel, then
> it would be best to ping someone in #fuel-dev on IRC and we can try to
> figure out how to get this applied upstream correctly. Our best
> results come from fixing upstream and I want to make sure that is
> clear.
> If you have specific bugs or commits you'd like to discuss, let's work
> them out. I believe I can get the Fuel Library team to agree to do a
> walk through all the open bugs in Puppet OpenStack and see if we have
> any related fixes or bug reports.
> Best Regards,
> Matthew Mosesohn
> On Thu, Jun 11, 2015 at 2:34 PM, Sanjay Upadhyay <saneax at gmail.com> wrote:
>> +1 for the thread, I would also like to hear from Mirantis on this.
>> The Fork on fuel/puppet has been actively seen patching and consolidation.It
>> seems like parallel effort why not merge it.
>> regards
>> /sanjay
>> On Thu, Jun 11, 2015 at 9:12 AM, Emilien Macchi <emilien at redhat.com> wrote:
>>> Hi,
>>> Before reading this e-mail, please keep in mind:
>>> * I have a lot of admiration for Fuel and since I'm working on OpenStack
>>> Installers (at eNovance and now Red Hat), Fuel is something I always
>>> consider a good product.
>>> * This e-mail is about Fuel and Puppet, nothing about Mirantis.
>>> * I'm writing on behalf of my thoughts, and not on our group.
>>> * I'm using open mailing-list for open discussion. There is not bad
>>> spirit in this e-mail and I want to have a productive thread.
>>> I have some concerns I would like to share with you and hopefully find
>>> some solutions together.
>>> Since I've been working on Puppet OpenStack (2 years now), I see some
>>> situations that happen - according to me - too often:
>>> * A bug is reported in both Fuel Library and the Puppet module having
>>> trouble. A patch is provided in Fuel Library (your fork of Puppet
>>> OpenStack modules) but not in Puppet upstream module. That means you fix
>>> the bug for Fuel, and not for Puppet OpenStack community. It does not
>>> happen all the time but quite often.
>>> * A patch is submitted in a Puppet module and quite often does not land
>>> because there is no activity, no tests or is abandonned later because
>>> fixed in Fuel Library. I've noticed the patch is fixed in Fuel Library
>>> though.
>>> * RAW copy/paste between upstream modules code and your forks. In term
>>> of Licensing, I'm even not sure you have the right to do that (I'm not a
>>> CLA expert though) but well... in term of authorship and statistics on
>>> code, I'm not sure it's fair. Using submodules with custom patches would
>>> have been great to respect the authors who created the original code and
>>> you could have personalize the manifests.
>>> Note: you can see that I don't give any example because I'm not here to
>>> blame people or judge anyone.
>>> So the goal of my e-mail is to open the discussion and have a *real*
>>> collaboration between Fuel team which seems to have a lot of good Puppet
>>> engineers and Puppet OpenStack team.
>>> We had this kind of discussion at the Summit (in Vancouver and also
>>> Paris, and even before). Now I would like to officialy know if you are
>>> interested or not to be more involved.
>>> I'm also open at any feedback about Puppet OpenStack group and if
>>> something blocks you to contribute more.
>>> We have the same goals, having Puppet modules better. I think it can be
>>> win/win: you have less diff with upstream and we have more hands in our
>>> module maintenance.
>>> Thank you for reading so far, and I'm looking forward to reading from you.
>>> Best regards,
>>> --
>>> Emilien Macchi
>>> __________________________________________________________________________
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>> --
>> Sanjay Upadhyay
>> http://saneax.blogspot.com
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