apache/hadoop · error · HadoopIllegalArgumentException

Must specify either -getlevel or -setlevel

Error message

Must specify either -getlevel or -setlevel

What it means

After the whole argument vector parses cleanly, LogLevel.CLI verifies an operation was actually selected; if operation is still UNKNOWN it throws HadoopIllegalArgumentException. This catches inputs where every token was individually valid but none of them chose -getlevel/-setlevel — the classic case being '-protocol http' alone.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/log/LogLevel.java:162

        throw new HadoopIllegalArgumentException("No arguments specified");
      }
      int nextArgIndex = 0;
      while (nextArgIndex < args.length) {
        if (args[nextArgIndex].equals("-getlevel")) {
          nextArgIndex = parseGetLevelArgs(args, nextArgIndex);
        } else if (args[nextArgIndex].equals("-setlevel")) {
          nextArgIndex = parseSetLevelArgs(args, nextArgIndex);
        } else if (args[nextArgIndex].equals("-protocol")) {
          nextArgIndex = parseProtocolArgs(args, nextArgIndex);
        } else {
          throw new HadoopIllegalArgumentException(
              "Unexpected argument " + args[nextArgIndex]);
        }
      }

      // 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) {

View on GitHub (pinned to 2add963021)

Solutions

1. Add the missing operation flag: '-getlevel <host:port> <classname>' or '-setlevel <host:port> <classname> <level>'.
2. Fix the constructing script so the operation variable cannot expand to nothing.
3. Check the printed usage (run() calls printUsage on this failure) and mirror its exact shape.

Example fix

# before
hadoop loglevel -protocol https namenode:9871

# after
hadoop loglevel -getlevel namenode:9871 org.apache.hadoop.ipc.Server -protocol https

boolean hasOp = Arrays.stream(args).anyMatch(a -> a.equals("-getlevel") || a.equals("-setlevel"));
if (!hasOp) {
  throw new HadoopIllegalArgumentException("Must include -getlevel or -setlevel");
}
ToolRunner.run(new LogLevel.CLI(conf), args);

When it happens

Trigger: Running 'hadoop loglevel -protocol http' (protocol given, no operation); passing only generic options that survive into the parser as no-ops; a script that assembles the command but drops the operation flag due to an empty variable.

Common situations: Copy-paste commands that lost their first token; scripts where the OPERATION variable is empty; users assuming the tool defaults to -getlevel when only a protocol is given.

Related errors

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

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/8c485efa31862840. Report an issue: GitHub.