Change LogLevel For MRAppMaster

Sometimes we want to show the debug log in MRAppMaster, there are two methods to do it. The first one is to change the mapred-site.xml in your gateway where you submit the job, add this conf.

<property>
<name>yarn.app.mapreduce.am.log.level</name>
<value>DEBUG</value>
</property>

The second one is to add config in the submit command like this

hadoop jar /usr/local/hadoop-2.4.0/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.4.0.jar terasort -Dmapred.reduce.tasks=50 -Dmapreduce.map.speculative=false -Dmapreduce.reduce.speculative=false -Dyarn.app.mapreduce.am.log.level=DEBUG /test/1001 /test/1001_SORT14