[HADOOP-9450] HADOOP_USER_CLASSPATH_FIRST is not honored; CLASSPATH is PREpended instead of APpended

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1-win, 2.1.0-beta, 1.3.0
• Component/s: scripts
• Hadoop Flags: Reviewed
• Assignee: Harsh J
• Reporter: Mitch Wyle
• Created: 02/Apr/13 00:00
• Updated: 18/Mar/15 00:25
• Resolved: 18/Apr/13 08:17

Description

On line 133 of the hadoop shell wrapper, CLASSPATH is set as:

CLASSPATH=${CLASSPATH}:${HADOOP_CLASSPATH}

Notice that the built-up CLASSPATH, along with all the libs and unwanted JARS are pre-pended BEFORE the user's HADOOP_CLASSPATH. Therefore there is no way to put your own JARs in front of those that the hadoop wrapper script sets.

We propose a patch that reverses this order. Failing that, we would like to add a command line option to override this behavior and enable a user's JARs to be found before the wrong ones in the Hadoop library paths.

We always welcome your opinions.

Issue Links

• is related to: HADOOP-9496 Bad merge of HADOOP-9450 on branch-2 breaks all bin/hadoop calls that need HADOOP_CLASSPATH