override default jvm reuse value

Question

We have mapred.job.reuse.jvm.num.tasks setting as -1(i.e to have jvm reuse with no limit) in hadoop's mapred-site.xml . But i want to override this property in one of my mapred job. Is it possible to override this value to 1 only for one job.

Answer 1

You can override any property which is not marked as final in respective configuration.xml file. To do this

1. Pass commandline argument to -D property_name=value.

2. Or by configuring in you mapred job by

   Configuration.set("property_name", "value");

Answer 2

You could use public void setNumTasksToExecutePerJvm(int numTasks). It allows us to set the number of tasks that a spawned task JVM should run before it exits