What causes "Bad option value {} found for {}" in apache/hadoop?

Set both unit counts to positive integers (numDataUnits >= 1, numParityUnits >= 1)

apache/hadoop · error · IllegalArgumentException

Bad option value {} found for {}

Error message

Bad option value {} found for {}

What it means

Inside ECSchema.extractIntOption, a unit-count value that parses as an integer but is <= 0 (zero or negative) throws IllegalArgumentException naming the value and the key. Erasure schemas need at least one data unit and usually at least one parity unit, so non-positive counts are meaningless and rejected at construction.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/ECSchema.java:137

    this.numDataUnits = numDataUnits;
    this.numParityUnits = numParityUnits;

    if (extraOptions == null) {
      extraOptions = new HashMap<>();
    }

    // After some cleanup
    this.extraOptions = Collections.unmodifiableMap(extraOptions);
  }

  private int extractIntOption(String optionKey, Map<String, String> options) {
    int result = -1;

    try {
      if (options.containsKey(optionKey)) {
        result = Integer.parseInt(options.get(optionKey));
        if (result <= 0) {
          throw new IllegalArgumentException("Bad option value " + result +
              " found for " + optionKey);
        }
      }
    } catch (NumberFormatException e) {
      throw new IllegalArgumentException("Option value " +
          options.get(optionKey) + " for " + optionKey +
          " is found. It should be an integer");
    }

    return result;
  }

  /**
   * Get the codec name
   * @return codec name
   */
  public String getCodecName() {
    return codecName;

View on GitHub (pinned to 2add963021)

Solutions

Set both unit counts to positive integers (numDataUnits >= 1, numParityUnits >= 1)
Trace where the zero/negative value came from if the map is generated (defaults, arithmetic, config placeholders)
Validate counts (> 0, and parity <= a sane maximum for the codec) before constructing the schema

Example fix

// before
opts.put("codec", "rs");
opts.put("numDataUnits", "0"); // placeholder never set
opts.put("numParityUnits", "3");
new ECSchema(opts); // throws: Bad option value 0 found for numDataUnits

// after
opts.put("numDataUnits", "6");

Defensive patterns

Strategy: validation

Validate before calling

for (String k : new String[]{"numDataUnits", "numParityUnits"}) {
  if (allOptions.containsKey(k)) {
    int v = Integer.parseInt(allOptions.get(k).trim());
    if (v <= 0) throw new IllegalArgumentException(k + " must be > 0, got " + v);
  }
}
new ECSchema(allOptions);

Try / catch

catch (IllegalArgumentException e) when message starts with 'Bad option value' -> map to a user-facing validation error naming the field.

Prevention

Validate unit counts as positive integers in your policy-editing UI or config loader before they reach ECSchema
Reject placeholder values like 0 at ingestion time
Cross-check parity counts against codec limits (e.g., RS parity typically <= 6) when authoring policies

When it happens

Trigger: new ECSchema(map) with "numDataUnits" = "0" or a negative number like "-1"; defaults or placeholders ("0") that were never replaced by real values; arithmetic that computed a zero count before building the map.

Common situations: Template policy files with 0 placeholders; code that derives counts from ratios or subtraction and can produce 0; misconfigured generated XML where a missing element was defaulted to 0.

Related errors

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/f1fbe4ad8c19c668. Report an issue: GitHub.