apache/hadoop · critical · IllegalArgumentException

callqueue.capacity.weights must specify ${priorityLevels} ca

Error message

callqueue.capacity.weights must specify ${priorityLevels} capacity weights: one for each priority level

What it means

CallQueueManager.parseCapacityWeights reads ipc.<port>.callqueue.capacity.weights (an int list). If the list is empty, equal default weights are used; if it is non-empty but its length differs from the configured scheduler priority levels, this IllegalArgumentException is thrown because each priority level needs exactly one capacity weight.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/CallQueueManager.java:424

    }
    if(retval < 1) {
      throw new IllegalArgumentException("numLevels must be at least 1");
    }
    return retval;
  }

  /**
   * Read the weights of capacity in callqueue and pass the value to
   * callqueue constructions.
   */
  private static int[] parseCapacityWeights(
      int priorityLevels, String ns, Configuration conf) {
    int[] weights = conf.getInts(ns + "." +
      CommonConfigurationKeys.IPC_CALLQUEUE_CAPACITY_WEIGHTS_KEY);
    if (weights.length == 0) {
      weights = getDefaultQueueCapacityWeights(priorityLevels);
    } else if (weights.length != priorityLevels) {
      throw new IllegalArgumentException(
          CommonConfigurationKeys.IPC_CALLQUEUE_CAPACITY_WEIGHTS_KEY + " must "
              + "specify " + priorityLevels + " capacity weights: one for each "
              + "priority level");
    } else {
      // only allow positive numbers
      for (int w : weights) {
        if (w <= 0) {
          throw new IllegalArgumentException(
              CommonConfigurationKeys.IPC_CALLQUEUE_CAPACITY_WEIGHTS_KEY +
                  " only takes positive weights. " + w + " capacity weight " +
                  "found");
        }
      }
    }
    return weights;
  }

  /**

View on GitHub (pinned to 2add963021)

Solutions

1. Count your weights and make them equal ipc.<port>.scheduler.priority.levels (e.g., '10,5,3,1' for 4 levels).
2. Or remove callqueue.capacity.weights entirely to get equal default weights per level.
3. Double-check the effective priority levels value — the mismatch is often on the levels side, not the weights side.
4. Watch for the deprecated ipc.<port>.callqueue.priority.levels overriding your intended level count.

Example fix

# before
<property><name>ipc.8020.scheduler.priority.levels</name><value>4</value></property>
<property><name>ipc.8020.callqueue.capacity.weights</name><value>4,3</value></property> <!-- 2 != 4 -->

# after
<property><name>ipc.8020.callqueue.capacity.weights</name><value>4,3,2,1</value></property>

int levels = conf.getInt("ipc.8020.scheduler.priority.levels", 4);
int[] weights = conf.getInts("ipc.8020.callqueue.capacity.weights");
if (weights != null && weights.length > 0) {
  Preconditions.checkArgument(weights.length == levels,
      "need exactly %s weights, got %s", levels, weights.length);
}

When it happens

Trigger: Setting ipc.<port>.callqueue.capacity.weights to a comma-separated list whose count differs from ipc.<port>.scheduler.priority.levels — e.g., weights '4,3,2,1' while priority.levels is 5, or a single '3' while levels is the default 4.

Common situations: Tuning FairCallQueue capacity distribution on NameNode/ResourceManager ports; changing scheduler.priority.levels without updating the weights list; trailing commas or parsing artifacts producing a different element count than intended.

Related errors

• numLevels must be at least 1
• callqueue.capacity.weights only takes positive weights. ${w}
• ${theClass.getName()} could not be constructed.
• Illegal field separator: ${separator}
• value cannot be blank

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/36162be2a323ee84. Report an issue: GitHub.