mkdir: Permission denied: user=yarn, access=WRITE, inode="/user/root/testdir":root:hdfs:drwxr-xr-x
Failing Oozie Launcher, Main class [org.apache.oozie.action.hadoop.ShellMain], exit code 
log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.impl.MetricsSystemImpl).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
How to fix this?
To tell oozie not to run container as yarn but as the user who has submitted the workflow, we need to add below variable environment variable in our workflow.xml file