code: private void setgidPermissionOnExecutionDirectory() throws IOException {
      logger.info("Creating subprocess to run shell command: chmod g+s "
          + this.executionDirectory.toString());
      Runtime.getRuntime().exec("chmod g+s " + this.executionDirectory.toString());
    }
docs: Setting the gid bit on the execution directory forces all files/directories created within the
  directory to be a part of the group associated with the azkaban process. Then, when users
  create their own files, the azkaban cleanup thread can properly remove them.
  
  Java does not provide a standard library api for setting the gid bit because the gid bit is
  system dependent, so the only way to set this bit is to start a new process and run the shell
  command "chmod g+s " + execution directory name.
  
  Note that this should work on most Linux distributions and MacOS, but will not work on
  Windows.