[YARN-6999] Add log about how to solve Error: Could not find or load main class org.apache.hadoop.mapreduce.v2.app.MRAppMaster

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-beta1
• Fix Version/s: 2.9.0, 3.0.0-beta1
• Component/s: documentation, security
• Labels: newbie

Environment

All operating systems.

• Target Version/s: 3.0.0-beta1
• Hadoop Flags: Reviewed
• Assignee: Linlin Zhou
• Reporter: Linlin Zhou
• Created: 12/Aug/17 00:30
• Updated: 30/Oct/17 10:39
• Resolved: 26/Aug/17 05:50

Description

According Setting up a Single Node Cluster https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/SingleCluster.html, we would still failed to run the MapReduce job example. Due to a security fix, yarn use user's environment variables to init, and user's environment variable usually doesn't include MapReduce related settings. So we need to add the related config in etc/hadoop/mapred-site.xml manually. Currently the log only tells there is an Error:
Could not find or load main class org.apache.hadoop.mapreduce.v2.app.MRAppMaster, without suggestion on how to solve it. I want to add the useful suggestion in log.