[YARN-10191] FS-CS converter: call System.exit function call for every code path in main method

• Type: Sub-task
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 3.3.0
• Hadoop Flags: Reviewed
• Assignee: Peter Bacsko
• Reporter: Peter Bacsko
• Created: 11/Mar/20 10:22
• Updated: 12/Mar/20 10:04
• Resolved: 12/Mar/20 09:34

Description

Note that we don't call System.exit() on the happy path scenario in the converter:

  public static void main(String[] args) {
    try {
      FSConfigToCSConfigArgumentHandler fsConfigConversionArgumentHandler =
          new FSConfigToCSConfigArgumentHandler();
      int exitCode =
          fsConfigConversionArgumentHandler.parseAndConvert(args);
      if (exitCode != 0) {
        LOG.error(FATAL,
            "Error while starting FS configuration conversion, " +
                "see previous error messages for details!");
        System.exit(exitCode);
      }
    } catch (Throwable t) {
      LOG.error(FATAL,
          "Error while starting FS configuration conversion!", t);
      System.exit(-1);
    }
  }
 

This is a mistake. If there's any non-daemon thread hanging around which was started by either FS or CS, the tool will never terminate. We must call System.exit() in every occasion to make sure that it never blocks at the end.