As it turns out, it looks like it's because the version of maven-jar-plugin in Fedora was upgraded, and hadoop's build takes advantage of the fact that older maven-jar-plugin versions don't notice clobbering artifacts with altered ones. This is probably going to bite Hadoop (if not already) when upgrading to ASF parent pom 18, which specifies the newest maven-jar-plugin.
The solution, which was suggested to me on the Fedora lists, is to skip the default-jar execution of the maven-jar-plugin, so that only the customized execution would run: <execution> <id>default-jar</id> <phase>skip</phase> </execution> Unfortunately, maven-jar-plugin doesn't seem to provide a proper "skip" flag (all plugins should!), so one has got to hack the execution by instructing it to run on a non-existing phase. Alternatively, Hadoop should really override the "default-jar" execution with its own configuration (which as far as I can tell, it just makes the jar build earlier in the lifecycle; side note: this is the wrong way to go... the "unit test" described in the comment, which requires the main jar, should probably be an "integration test"). Thoughts? (I'm not sure why the build worked for me fine in x86_64, vs. i686, but it appears to be a fluke... maybe I had an older version of maven-jar-plugin installed already?) On Fri, Jun 17, 2016 at 5:45 PM Christopher <ctubb...@apache.org> wrote: > It's possible it's a problem with the Fedora-packaged Maven or the jar > plugin. However, I was able to do a mock build (mock in Fedora uses > containers) to build it fine on x86_64. I've been given a hint as to how to > tell mock to use a different arch, but haven't yet had a chance to try it. > > Mainly, I just want to make sure it's supported upstream. If it's not, and > never will be, then I can use ExcludeArch in the RPM spec. Otherwise, I've > gotta try to figure out why it's broken. > > On Thu, Jun 16, 2016 at 4:31 PM Chris Nauroth <cnaur...@hortonworks.com> > wrote: > >> Thank you for sharing that. >> >> I was expecting to see some kind of failure in building our C codebase, >> where a 32-bit vs. 64-bit portability problem is likely to happen. >> Instead, that's a failure in Maven's handling of a jar dependency. I tried >> building from the 2.4.0 source, and I couldn't reproduce the problem. >> >> Is it possible that this is a problem specific to the Maven version >> running your build? The BUILDING.txt file in the root of the source tree >> has details on what tools and what versions are required for the build. >> >> --Chris Nauroth >> >> From: Christopher <ctubb...@apache.org> >> Date: Thursday, June 16, 2016 at 12:48 PM >> To: Chris Nauroth <cnaur...@hortonworks.com>, "user@hadoop.apache.org" < >> user@hadoop.apache.org> >> Subject: Re: i686 support >> >> Well, the error I got was: >> >> [ERROR] Failed to execute goal >> org.apache.maven.plugins:maven-jar-plugin:3.0.1:jar (default-jar) on project >> hadoop-yarn-applications-distributedshell: You have to use a classifier to >> attach supplemental artifacts to the project instead of replacing them. -> >> [Help 1] >> >> >> https://kojipkgs.fedoraproject.org//work/tasks/1712/14521712/build.log >> >> I'm not sure if this is a Fedora-specific problem (due to its dependency >> convergence and the specific version of the maven-jar-plugin, for example), >> or if it's an upstream problem. This was version 2.4.1. Right now, I'm just >> trying to stabilize the currently packaged 2.4 version, before I begin >> moving towards an upgrade path for users to migrate to a newer version >> (2.6, probably). It's just that I'm a bit overwhelmed with Hadoop's build >> and quantity of components. >> >> Not sure where to begin looking. >> >> On Thu, Jun 16, 2016 at 3:42 PM Chris Nauroth <cnaur...@hortonworks.com> >> wrote: >> >>> Hello Christopher, >>> >>> While 64-bit is certainly the common case at this point, we also have >>> produced 32-bit builds in the past. I'm not aware of any conscious choice >>> by the community to halt 32-bit support, so if that's not working, then it >>> might be a bug. Do you have more details on the build failure? That might >>> help us confirm if it's a bug, and if so, move to tracking it in an Apache >>> JIRA. >>> >>> --Chris Nauroth >>> >>> From: Christopher <ctubb...@apache.org> >>> Date: Thursday, June 16, 2016 at 12:35 PM >>> To: "user@hadoop.apache.org" <user@hadoop.apache.org> >>> Subject: i686 support >>> >>> Hi, >>> >>> Is i686 a supported arch by the upstream Hadoop developers? I'm trying >>> to package hadoop RPMs for Fedora (reviving somebody else's previous >>> efforts), and can't get things to build on i686. Is this normal? Does >>> upstream care about 32-bit users? What about release testing on i686? >>> >>> I normally wouldn't care about 32-bit, but Fedora packaging standards >>> encourage me to get it to work for all core architectures supported by >>> Fedora. >>> >>> Has anybody else done any 32-bit packaging that could help me >>> troubleshoot? I don't even own 32-bit hardware. (Even better if you want to >>> help co-maintain Hadoop in Fedora.. that would be awesome). >>> >>>
