[HADOOP-14976] Set HADOOP_SHELL_EXECNAME explicitly in scripts

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.1.0
• Hadoop Flags: Reviewed
• Assignee: Arpit Agarwal
• Reporter: Arpit Agarwal
• Created: 24/Oct/17 19:25
• Updated: 05/Dec/17 05:23
• Resolved: 05/Dec/17 05:05

Description

Some Hadoop shell scripts infer their own name using this bit of shell magic:

 18     MYNAME="${BASH_SOURCE-$0}"
 19     HADOOP_SHELL_EXECNAME="${MYNAME##*/}"

e.g. see the hdfs script.

The inferred shell script name is later passed to hadoop-functions.sh which uses it to construct the names of some environment variables. E.g. when invoking hdfs datanode, the options variable name is inferred as follows:

# HDFS + DATANODE + OPTS -> HDFS_DATANODE_OPTS

This works well if the calling script name is standard hdfs or yarn. If a distribution renames the script to something like foo.bar, , then the variable names will be inferred as FOO.BAR_DATANODE_OPTS. This is not a valid bash variable name.