apache/hadoop · error · HadoopIllegalArgumentException

Redundant -getlevel command

Error message

Redundant -getlevel command

What it means

parseGetLevelArgs throws HadoopIllegalArgumentException('Redundant -getlevel command') when a second -getlevel flag is encountered, because the operation enum is already set to GETLEVEL. The log-level tool accepts exactly one operation per invocation; combining or repeating operations is rejected at parse time.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/log/LogLevel.java:176

      }

      // if operation is never specified in the arguments
      if (operation == Operations.UNKNOWN) {
        throw new HadoopIllegalArgumentException(
            "Must specify either -getlevel or -setlevel");
      }

      // if protocol is unspecified, set it as http.
      if (protocol == null) {
        protocol = PROTOCOL_HTTP;
      }
    }

    private int parseGetLevelArgs(String[] args, int index) throws
        HadoopIllegalArgumentException {
      // fail if multiple operations are specified in the arguments
      if (operation != Operations.UNKNOWN) {
        throw new HadoopIllegalArgumentException(
            "Redundant -getlevel command");
      }
      // check number of arguments is sufficient
      if (index+2 >= args.length) {
        throw new HadoopIllegalArgumentException(
            "-getlevel needs two parameters");
      }
      operation = Operations.GETLEVEL;
      hostName = args[index+1];
      className = args[index+2];
      return index+3;
    }

    private int parseSetLevelArgs(String[] args, int index) throws
        HadoopIllegalArgumentException {
      // fail if multiple operations are specified in the arguments
      if (operation != Operations.UNKNOWN) {
        throw new HadoopIllegalArgumentException(

View on GitHub (pinned to 2add963021)

Solutions

1. Remove the duplicate — issue exactly one -getlevel (or one -setlevel) per invocation.
2. Run separate invocations for separate queries instead of chaining flags.
3. Fix the script that builds the command so it appends the operation exactly once.

Example fix

# before
hadoop loglevel -getlevel nn:9870 A -getlevel nn:9870 B

# after
hadoop loglevel -getlevel nn:9870 A && hadoop loglevel -getlevel nn:9870 B

long n = Arrays.stream(args).filter(a -> a.equals("-getlevel")).count();
if (n > 1) {
  throw new HadoopIllegalArgumentException("-getlevel may appear only once");
}

When it happens

Trigger: 'hadoop loglevel -getlevel h:9870 cls -getlevel h:9870 cls2'; a duplicated flag from a shell loop or a for-loop bug appending the flag twice; copy-paste concatenation of two commands.

Common situations: Bash history editing duplicating a flag; wrapper scripts appending '-getlevel ...' to a variable that already contained it; documentation examples pasted back to back.

Related errors

• Redundant -setlevel command
• Redundant -protocol command
• Expect either -getlevel or -setlevel
• No arguments specified
• "Unexpected argument " + args[nextArgIndex]

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/6428aef384bbb119. Report an issue: GitHub.