apache/hadoop · error · IllegalArgumentException

Not a valid Boolean value for {property}

Error message

Not a valid Boolean value for {property}

What it means

Live reconfiguration of dfs.disk.balancer.enabled in reconfDiskBalancerParameters accepts only "true" or "false" (case-insensitive); any other non-null value raises IllegalArgumentException('Not a valid Boolean value for ...') which the method wraps into ReconfigurationException. A null newVal resets to the DFS_DISK_BALANCER_ENABLED default and never fails. The old value stays in effect when the change is rejected.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:1035

          }
        }
      }
      LOG.info("RECONFIGURE* changed {} to {}", property, newVal);
      return result;
    } catch (IllegalArgumentException | IOException | ClassNotFoundException e) {
      throw new ReconfigurationException(property, newVal, getConf().get(property), e);
    }
  }

  private String reconfDiskBalancerParameters(String property, String newVal)
      throws ReconfigurationException {
    String result = null;
    try {
      LOG.info("Reconfiguring {} to {}", property, newVal);
      if (property.equals(DFS_DISK_BALANCER_ENABLED)) {
        if (newVal != null && !newVal.equalsIgnoreCase("true")
            && !newVal.equalsIgnoreCase("false")) {
          throw new IllegalArgumentException("Not a valid Boolean value for " + property);
        }
        boolean enable = (newVal == null ? DFS_DISK_BALANCER_ENABLED_DEFAULT :
            Boolean.parseBoolean(newVal));
        getDiskBalancer().setDiskBalancerEnabled(enable);
        result = Boolean.toString(enable);
      } else if (property.equals(DFS_DISK_BALANCER_PLAN_VALID_INTERVAL)) {
        if (newVal == null) {
          // set to default
          long defaultInterval = getConf().getTimeDuration(
              DFS_DISK_BALANCER_PLAN_VALID_INTERVAL,
              DFS_DISK_BALANCER_PLAN_VALID_INTERVAL_DEFAULT,
              TimeUnit.MILLISECONDS);
          getDiskBalancer().setPlanValidityInterval(defaultInterval);
          result = DFS_DISK_BALANCER_PLAN_VALID_INTERVAL_DEFAULT;
        } else {
          long newInterval = getConf()
              .getTimeDurationHelper(DFS_DISK_BALANCER_PLAN_VALID_INTERVAL,
                  newVal, TimeUnit.MILLISECONDS);

View on GitHub (pinned to 2add963021)

Solutions

  1. Resubmit exactly true or false with no surrounding whitespace
  2. Fix the template/source that produced the value so it emits only true/false
  3. Verify with hdfs dfsadmin -reconfig datanode <dn:ipc> status that the old value survived

Example fix

// before
$ hdfs dfsadmin -reconfig datanode dn1:9867 start ... dfs.disk.balancer.enabled=1
// after
$ hdfs dfsadmin -reconfig datanode dn1:9867 start ... dfs.disk.balancer.enabled=true
Defensive patterns

Strategy: validation

Validate before calling

static boolean isDnBooleanLiteral(String v) {
  return v == null || v.equalsIgnoreCase("true") || v.equalsIgnoreCase("false");
}
if (!isDnBooleanLiteral(newVal)) throw new IllegalArgumentException("dfs.disk.balancer.enabled accepts only true/false");

Try / catch

catch (ReconfigurationException e) {
  // cause IllegalArgumentException('Not a valid Boolean value for ...'); old value retained
  LOG.warn("Rejected: {}", e.getMessage());
}

Prevention

When it happens

Trigger: Calling 'hdfs dfsadmin -reconfig datanode ... start' or the reconfig JMX/HTTP API for dfs.disk.balancer.enabled with "1", "yes", "on", an empty string, or whitespace-padded values like " true" (equalsIgnoreCase fails on any extra characters).

Common situations: Turning disk balancer on/off across a fleet with scripts that use 1/0; config templates rendering booleans inconsistently per key; copy-paste from docs that show 'enable: yes'.

Related errors

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/6a18518f527ba721. Report an issue: GitHub.