How Do I Set the Task Priority When Submitting a MapReduce Task?

Question

How do I set the job priority when submitting a MapReduce task?

Answer

You can add the parameter -Dmapreduce.job.priority=<priority> in the command to set task priority when submitting MapReduce tasks on the client. The format is as follows:

yarn jar <jar> [mainClass] -Dmapreduce.job.priority=<priority> [path1] [path2]

The parameters in the command are described as follows:

• <jar>: specifies the name of the JAR package to be run.
• [mainClass]: specifies the main method of the class for an application project in a JAR file.
• <priority>: specifies the priority of a task. The value can be VERY_HIGH, HIGH, NORMAL, LOW, or VERY_LOW.

• [path1]: specifies the data input path.
• [path2]: specifies the data output path.

For example, set the /opt/client/HDFS/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-xxx.jar package to a high-priority task.

yarn jar /opt/client/HDFS/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-xxx.jar wordcount -Dmapreduce.job.priority=VERY_HIGH /DATA.txt /out/