Hadoop Common
  1. Hadoop Common
  2. HADOOP-4340

"hadoop jar" always returns exit code 0 (success) to the shell when jar throws a fatal exception

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 0.18.1, 0.19.0, 0.20.0
    • Fix Version/s: 0.18.2
    • Component/s: None
    • Labels:
      None
    • Environment:

      Ubuntu 8.04 Server, 7 Hadoop nodes, GNU bash, version 3.2.39(1)-release (i486-pc-linux-gnu)

    • Hadoop Flags:
      Reviewed

      Description

      Running "hadoop jar" always returns 0 (success) when the jar dies with a stack trace. As an example, run these commands:

      /usr/local/hadoop/bin/hadoop jar /usr/local/hadoop/hadoop-0.18.1-examples.jar pi 10 10 2>&1; echo $?
      exits with 0

      /usr/local/hadoop/bin/hadoop jar /usr/local/hadoop/hadoop-0.18.1-examples.jar pi 2>&1; echo $?
      exits with 255

      /usr/local/hadoop/bin/hadoop jar /usr/local/hadoop/hadoop-0.18.1-examples.jar 2>&1; echo $?
      exits with 0

      This seems to be expected behavior. However, running:

      /usr/local/hadoop/bin/hadoop jar /usr/local/hadoop/hadoop-0.18.1-examples.jar pi 10 badparam 2>&1; echo $?
      java.lang.NumberFormatException: For input string: "badparam"
      at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
      at java.lang.Long.parseLong(Long.java:403)
      at java.lang.Long.parseLong(Long.java:461)
      at org.apache.hadoop.examples.PiEstimator.run(PiEstimator.java:241)
      at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
      at org.apache.hadoop.examples.PiEstimator.main(PiEstimator.java:252)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:68)
      at org.apache.hadoop.util.ProgramDriver.driver(ProgramDriver.java:139)
      at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:53)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at org.apache.hadoop.util.RunJar.main(RunJar.java:155)
      at org.apache.hadoop.mapred.JobShell.run(JobShell.java:54)
      at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
      at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:79)
      at org.apache.hadoop.mapred.JobShell.main(JobShell.java:68)
      exits with 0.

      In my opinion, if a jar throws an exception that kills the program being run, and the developer doesn't catch the exception and do a sane exit with a exit code, hadoop should at least exit with a non-zero exit code.

      As another example, while running a main class that exits with an exit code of 201, Hadoop will preserve the correct exit code:

      public static void main(String[] args) throws Exception

      { System.exit(201); }

      But when deliberately creating a null pointer exception, Hadoop exits with 0.

      public static void main(String[] args) throws Exception

      { Object o = null; o.toString(); System.exit(201); }

      This behaviour makes it very difficult, if not impossible, to use Hadoop programatically with tools such as HOD or non-Java data processing frameworks, since if a jar crashes with an unhandled exception, Hadoop doesn't inform the calling program in a well-bahaved way (polling stderr for output is not a very good way to detect application failure).

      I'm not a Java programmer, so I don't know what the best code to signal failure would be.

      Please let me know what other information I can include about my setup

      Thanks.

      1. HADOOP-4340_2_20081029.patch
        2 kB
        Arun C Murthy
      2. patch-4340.txt
        0.5 kB
        Amareshwari Sriramadasu
      3. patch-4340-1.txt
        0.9 kB
        Amareshwari Sriramadasu

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            • Assignee:
              Arun C Murthy
              Reporter:
              David Litster
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              Dates

              • Created:
                Updated:
                Resolved:

                Development