[YARN-2625] Problems with CLASSPATH in Job Submission REST API

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.5.1
• Component/s: api
• Assignee: Unassigned
• Reporter: Doug Haigh
• Created: 30/Sep/14 12:47
• Updated: 19/Oct/15 03:25

Description

There are a couple of issues I have found specifying the CLASSPATH environment variable using the REST API.

1) In the Java client, the CLASSPATH environment is usually made up of either the value of the yarn.application.classpath in yarn-site.xml value or the default YARN classpath value as defined by YarnConfiguration.DEFAULT_YARN_CROSS_PLATFORM_APPLICATION_CLASSPATH. REST API consumers have no method of telling the resource manager to use the default unless they hardcode the default value themselves. If the default ever changes, the code would need to change.

2) If any environment variables are used in the CLASSPATH environment 'value' field, they are evaluated when the values are NULL resulting in bad values in the CLASSPATH. For example, if I had hardcoded the CLASSPATH value to the default of "$HADOOP_CONF_DIR, $HADOOP_COMMON_HOME/share/hadoop/common/, $HADOOP_COMMON_HOME/share/hadoop/common/lib/, $HADOOP_HDFS_HOME/share/hadoop/hdfs/, $HADOOP_HDFS_HOME/share/hadoop/hdfs/lib/, $HADOOP_YARN_HOME/share/hadoop/yarn/, $HADOOP_YARN_HOME/share/hadoop/yarn/lib/" the classpath passed to the application master is ":/share/hadoop/common/:/share/hadoop/common/lib/:/share/hadoop/hdfs/:/share/hadoop/hdfs/lib/:/share/hadoop/yarn/:/share/hadoop/yarn/lib/"

These two problems require REST API consumers to always have the fully resolved path defined in the yarn.application.classpath value. If the property is missing or contains environment varaibles, the application created by the REST API will fail due to the CLASSPATH being incorrect.

Issue Links

• depends upon: YARN-4275 Rest API to expose YARN CLASSPATH and other useful system properties