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https://issues.apache.org/jira/browse/MAPREDUCE-3693?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Arun C Murthy resolved MAPREDUCE-3693.
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Resolution: Not A Problem
In MR2 the parent JVM i.e. MR AM is unrelated to child JVM (map/reduce) and
hence it's java.library.path isn't passed along.
Very different from MR1 which, arguably, was a bug to pass TT's
java.library.path to child (map/reduce).
This is a good time to not do this anymore.
Similarly, we shouldn't pass NM's library path either. It's the AM's
responsibility to set it up.
> mapreduce's MapReduceChildJVM no longer proxies value of java.library.path
> ---------------------------------------------------------------------------
>
> Key: MAPREDUCE-3693
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3693
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Affects Versions: 0.23.0
> Reporter: Roman Shaposhnik
> Fix For: 0.23.1
>
>
> I have noticed that org.apache.hadoop.mapred.MapReduceChildJVM doesn't
> forward the value of -Djava.library.path= from the parent JVM to the child
> JVM. Thus if one wants to use native libraries for compression the only
> option seems to be to manually include relevant java.library.path settings
> into the mapred-site.xml (as mapred.[map|reduce].child.java.opts).
> This seems to be a change in behavior compared to MR1 where TaskRunner.java
> used to do that:
> {noformat}
> String libraryPath = System.getProperty("java.library.path");
> if (libraryPath == null) {
> libraryPath = workDir.getAbsolutePath();
> } else {
> libraryPath += SYSTEM_PATH_SEPARATOR + workDir;
> }
> boolean hasUserLDPath = false;
> for(int i=0; i<javaOptsSplit.length ;i++) {
> if(javaOptsSplit[i].startsWith("-Djava.library.path=")) {
> javaOptsSplit[i] += SYSTEM_PATH_SEPARATOR + libraryPath;
> hasUserLDPath = true;
> break;
> }
> }
> if(!hasUserLDPath) {
> vargs.add("-Djava.library.path=" + libraryPath);
> }
> for (int i = 0; i < javaOptsSplit.length; i++) {
> vargs.add(javaOptsSplit[i]);
> }
> {noformat}
> Is this a regression or a deliberate choice?
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