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Posted to mapreduce-issues@hadoop.apache.org by "Hadoop QA (JIRA)" <ji...@apache.org> on 2014/04/15 23:08:15 UTC
[jira] [Commented] (MAPREDUCE-5837) MRAppMaster fails when checking
on uber mode
[ https://issues.apache.org/jira/browse/MAPREDUCE-5837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13970059#comment-13970059 ]
Hadoop QA commented on MAPREDUCE-5837:
--------------------------------------
{color:red}-1 overall{color}. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12640325/MAPREDUCE-5837.000.patch
against trunk revision .
{color:green}+1 @author{color}. The patch does not contain any @author tags.
{color:red}-1 tests included{color}. The patch doesn't appear to include any new or modified tests.
Please justify why no new tests are needed for this patch.
Also please list what manual steps were performed to verify this patch.
{color:green}+1 javac{color}. The applied patch does not increase the total number of javac compiler warnings.
{color:green}+1 javadoc{color}. There were no new javadoc warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new Findbugs (version 1.3.9) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase the total number of release audit warnings.
{color:green}+1 core tests{color}. The patch passed unit tests in hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app.
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4518//testReport/
Console output: https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/4518//console
This message is automatically generated.
> MRAppMaster fails when checking on uber mode
> --------------------------------------------
>
> Key: MAPREDUCE-5837
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5837
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Reporter: Haohui Mai
> Assignee: Haohui Mai
> Priority: Critical
> Attachments: MAPREDUCE-5837.000.patch
>
>
> When the MRAppMaster determines whether the job should run in the uber mode, it call {{Class.forName()}} to check whether the class is derived from {{ChainMapper}}:
> {code}
> try {
> String mapClassName = conf.get(MRJobConfig.MAP_CLASS_ATTR);
> if (mapClassName != null) {
> Class<?> mapClass = Class.forName(mapClassName);
> if (ChainMapper.class.isAssignableFrom(mapClass))
> isChainJob = true;
> }
> } catch (ClassNotFoundException cnfe) {
> // don't care; assume it's not derived from ChainMapper
> }
> {code}
> The problem here is that {{Class.forName()}} can also throw {{NoClassDefError}}. It happens when the additional dependent jar is unavailable to the MRAppMaster. For example, the MRAppMaster complains about a MR job on Scala:
> {noformat}
> 2014-04-15 11:52:55,877 FATAL [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Error starting MRAppMaster
> java.lang.NoClassDefFoundError: scala/Function1
> at java.lang.Class.forName0(Native Method)
> at java.lang.Class.forName(Class.java:190)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl.isChainJob(JobImpl.java:1282)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl.makeUberDecision(JobImpl.java:1224)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl.access$3700(JobImpl.java:136)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl$InitTransition.transition(JobImpl.java:1425)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl$InitTransition.transition(JobImpl.java:1363)
> at org.apache.hadoop.yarn.state.StateMachineFactory$MultipleInternalArc.doTransition(StateMachineFactory.java:385)
> at org.apache.hadoop.yarn.state.StateMachineFactory.doTransition(StateMachineFactory.java:302)
> at org.apache.hadoop.yarn.state.StateMachineFactory.access$300(StateMachineFactory.java:46)
> at org.apache.hadoop.yarn.state.StateMachineFactory$InternalStateMachine.doTransition(StateMachineFactory.java:448)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl.handle(JobImpl.java:976)
> at org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl.handle(JobImpl.java:135)
> at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$JobEventDispatcher.handle(MRAppMaster.java:1263)
> at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.serviceStart(MRAppMaster.java:1063)
> at org.apache.hadoop.service.AbstractService.start(AbstractService.java:193)
> at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$1.run(MRAppMaster.java:1480)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:415)
> at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1606)
> at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.initAndStartAppMaster(MRAppMaster.java:1476)
> at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.main(MRAppMaster.java:1409)
> Caused by: java.lang.ClassNotFoundException: scala.Function1
> at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
> at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
> at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
> ... 22 more
> {noformat}
>
> The proposed fix is to catch {{NoClassDefError}} at the corresponding places.
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