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Hadoop, mail # general - [DISCUSS] Spin out MR, HDFS and YARN as their own TLPs and disband Hadoop umbrella project


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Re: [DISCUSS] Spin out MR, HDFS and YARN as their own TLPs and disband Hadoop umbrella project
Roman Shaposhnik 2012-08-31, 15:59
On Tue, Aug 28, 2012 at 7:33 PM, Mattmann, Chris A (388J)
<[EMAIL PROTECTED]> wrote:
> [decided to minimize traffic and to simply put this in one thread]
>
> Hi Guys,
>
> See the recent discussion on these threads:
>
> YARN as its own Hadoop "sub project": http://s.apache.org/WW1
> Maintain a single committer list for the Hadoop project: http://s.apache.org/Owx
>
> ...and just pay attention to the Hadoop project over the last 3-4 years. It's operating
> as a single project, that's masking separate communities that themselves are really
> separate ASF projects.
>
> At the ASF, this has been a problem area called "umbrella" projects and over the years,
> all I've seen from them is wasted bandwidth, artificial barriers and the inventions of
> new ways to perform process mongering and to reduce the fun in developing software
> at this fantastic foundation.
>
> I've talked about umbrella projects enough. We've diverted conversation enough.
> Enough people have tried to act like there is some technical mumbo jumbo that is
> preventing the eventual act of higher power that I myself hope comes should these
> discussions prove unfruitful through normal means.
>
> *these. are. separate. projects.*
> *there.are.not.blocker.issues.from.spinning.out.these.projects.as.their.own.communities*
>
> In this email: http://s.apache.org/rSm
>
> And in the 2 subsequent follow ons in that thread, I've outlined a process that I'll copy
> through below for splitting these projects into their own TLPs:
>
> -----snip
> Process:
>
> 0. [DISCUSS] thread for <TLP name> in which you talk about #1 and #2 below, potentially draft resolution too.
>
> 1. Decide on an initial set of *PMC* members. I urge each new TLP to adopt PMC==C. See reasons I've
> already discussed.
>
> 2. Decide on a chair. Try not to VOTE for this explicitly, see if can be discussed and consensus
> can be reached (just a thought experiment). VOTE if necessary.
>
> 3. [VOTE] thread for <TLP name>
>
> 4. Create Project:
>   a. paste resolution from #0 to board@ or;
>   b. go to general@incubator and start new Incubator project.
>
> 5. infrastructure set up.
>    MLs moving; new UNIX groups; website setup;
>    SVN setup like this:
>
> svn copy -m "MR TLP." https://svn.apache.org/repos/asf/hadoop/ https://svn.apache.org/repos/asf/<insert cool MR name>; or
> svn copy -m "YARN TLP." https://svn.apache.org/repos/asf/hadoop/ https://svn.apache.org/repos/asf/<insert cool YARN name>; or
> svn copy -m "HDFS TLP." https://svn.apache.org/repos/asf/hadoop/ https://svn.apache.org/repos/asf/<insert cool HDFS name>
>
> After all 3 have been created run:
>
> svn remove -m "Remove Hadoop umbrella TLP. Split into separate projects." https://svn.apache.org/repos/asf/hadoop
>
> 6. (TLPs if 4a; Incubator podling if 4b;) proceed, collaborate, operate as distinct communities, and try to solve the code duplication/dependency
> issues from there.
>
> 7. If 4b; then graduate as TLP from Incubator.
>
> -----snip
>
> So that's my proposal.

+1 on the general idea of splitting the projects predicated on
fixing the issues that made the last split so painful and resolving
technicalities like dependencies, etc.

Here's a perspective of a downstream producer of a distribution
built on top of Hadoop: I firmly believe that at least with Hadoop 2.0
we've reached a point where HDFS and YARN/Mapreduce being
standalone loosely coupled projects would make much more sense.
The user community of Bigtop has expressed interest in being able to
mix-n-match versions of MR and HDFS and I believe this to be a
very valid (and achievable!) use case. It is less clear what to do
with the Hadoop 1.X code line, but my perception so far has been
that it is mainly in maintenance mode and thus could be dealt with
as an exceptional case.

I've heard some integration concerns on this thread and while I appreciate
them, I still believe that individual projects shouldn't be burdened by them
to the extent that they can maintain a reasonable compatibility of the APIs.
It is my personal opinion that HDFS and YARN/Mapreduce of the
Hadoop 2.0 are ready to do that. Bigtop is there to keep them honest, provided
that folks are willing to help us with that mission.

Thanks,
Roman.