[MAPREDUCE-2932] Missing instrumentation plugin class shouldn't crash the TT startup per design

• Type: Bug
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 1.1.0
• Component/s: tasktracker
• Hadoop Flags: Reviewed
• Assignee: Harsh J
• Reporter: Harsh J
• Created: 05/Sep/11 16:05
• Updated: 17/Oct/12 18:27
• Resolved: 22/Sep/11 19:23

Description

Per the implementation of the TaskTracker instrumentation plugin implementation (from 2008), a ClassNotFoundException during loading up of an configured TaskTracker instrumentation class shouldn't have hampered TT start up at all.

But, there is one class-fetching call outside try/catch, which makes TT fall down with a RuntimeException if there's a class not found. Would be good to include this line into the try/catch itself.

Strace would appear as:

2011-08-25 11:45:38,470 ERROR org.apache.hadoop.mapred.TaskTracker: Can not start task tracker because java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: org.apache.hadoop.mapred.CustomInstPlugin 
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java) 
at org.apache.hadoop.mapred.TaskTracker.getInstrumentationClass(TaskTracker.java) 
at org.apache.hadoop.mapred.TaskTracker.initialize(TaskTracker.java)