yarn modifies directory permissions

[#1]

yarn aggregation log on hdfs when I FINISHED a job, the {yarn.nodemanager.remote-app-log-dir}/{user}/{yarn.nodemanager.remote-app-log-dir-sendix} directory permission is 770, I change the directory permission to 775.

But when I FINISHED a yarn job, it change the directory permission to 770 again.

Why would he happen? How to get it not to modify directory permissions.

[#2]

Please check the umask that is set for the yarn directories.