[YARN-10593] Fix incorrect string comparison in GpuDiscoverer

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.4.0
• Component/s: resourcemanager
• Hadoop Flags: Reviewed
• Assignee: Peter Bacsko
• Reporter: Peter Bacsko
• Created: 25/Jan/21 12:58
• Updated: 10/Feb/21 12:10
• Resolved: 10/Feb/21 12:10

Description

The following comparison in GpuDiscoverer is invalid:

       binaryPath = configuredBinaryFile;
      // If path exists but file name is incorrect don't execute the file
      String fileName = binaryPath.getName();
      if (DEFAULT_BINARY_NAME.equals(fileName)) {  <--- inverse condition needed
        String msg = String.format("Please check the configuration value of"
             +" %s. It should point to an %s binary.",
             YarnConfiguration.NM_GPU_PATH_TO_EXEC,
             DEFAULT_BINARY_NAME);
        throwIfNecessary(new YarnException(msg), config);
        LOG.warn(msg);
      }

Obviously it should be other way around - we should log a warning or throw an exception if the file names differ, not when they're equal.

Consider adding a unit test for this.