apache/hadoop · error · IllegalArgumentException

Not a valid Boolean value for {property} in reconfSlowPeerPa

Error message

Not a valid Boolean value for {property} in reconfSlowPeerParameters

What it means

DataNode.reconfSlowPeerParameters applies live reconfigurations for slow-peer metrics; for dfs.datanode.peer.stats.enabled it accepts only the literal strings "true" or "false" (case-insensitive). Any other non-null value raises IllegalArgumentException('Not a valid Boolean value for ...'), which the method wraps into a ReconfigurationException naming the property, the old value, and the new value. The DataNode keeps running with the previous setting.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:870

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

  private String reconfSlowPeerParameters(String property, String newVal)
      throws ReconfigurationException {
    String result = null;
    try {
      LOG.info("Reconfiguring {} to {}", property, newVal);
      if (property.equals(DFS_DATANODE_PEER_STATS_ENABLED_KEY)) {
        Preconditions.checkNotNull(dnConf, "DNConf has not been initialized.");
        if (newVal != null && !newVal.equalsIgnoreCase("true")
            && !newVal.equalsIgnoreCase("false")) {
          throw new IllegalArgumentException("Not a valid Boolean value for " + property +
              " in reconfSlowPeerParameters");
        }
        boolean enable = (newVal == null ? DFS_DATANODE_PEER_STATS_ENABLED_DEFAULT :
            Boolean.parseBoolean(newVal));
        result = Boolean.toString(enable);
        dnConf.setPeerStatsEnabled(enable);
        if (enable) {
          // Create if it doesn't exist, overwrite if it does.
          peerMetrics = DataNodePeerMetrics.create(getDisplayName(), getConf());
        }
      } else if (property.equals(DFS_DATANODE_MIN_OUTLIER_DETECTION_NODES_KEY)) {
        Preconditions.checkNotNull(peerMetrics, "DataNode peer stats may be disabled.");
        long minNodes = (newVal == null ? DFS_DATANODE_MIN_OUTLIER_DETECTION_NODES_DEFAULT :
            Long.parseLong(newVal));
        result = Long.toString(minNodes);
        peerMetrics.setMinOutlierDetectionNodes(minNodes);
      } else if (property.equals(DFS_DATANODE_SLOWPEER_LOW_THRESHOLD_MS_KEY)) {
        Preconditions.checkNotNull(peerMetrics, "DataNode peer stats may be disabled.");

View on GitHub (pinned to 2add963021)

Solutions

1. Resubmit with the literal true or false: hdfs dfsadmin -reconfig datanode <dnHost:ipcPort> start <nnUri> dfs.datanode.peer.stats.enabled=true
2. Fix the upstream template or config-management source so it emits only true or false (no 1/0, no whitespace, no units)
3. Confirm the DN retained the old value and is healthy: hdfs dfsadmin -reconfig datanode <dnHost:ipcPort> status

Example fix

// before
$ hdfs dfsadmin -reconfig datanode dn1:9867 start hdfs://nn1:8020 dfs.datanode.peer.stats.enabled=yes
// => ReconfigurationException: Could not change property ... Not a valid Boolean value for dfs.datanode.peer.stats.enabled ...
// after
$ hdfs dfsadmin -reconfig datanode dn1:9867 start hdfs://nn1:8020 dfs.datanode.peer.stats.enabled=true

static boolean isDnBooleanLiteral(String v) {
  return v == null || v.equalsIgnoreCase("true") || v.equalsIgnoreCase("false");
}
// gate before submitting the reconfiguration
if (!isDnBooleanLiteral(newVal)) {
  throw new IllegalArgumentException("dfs.datanode.peer.stats.enabled accepts only true/false, got: " + newVal);
}

try {
  dn.reconfigurePropertyImpl(DFS_DATANODE_PEER_STATS_ENABLED_KEY, newVal);
} catch (ReconfigurationException e) {
  // message carries property + oldVal + newVal; cause is the IllegalArgumentException
  LOG.warn("Reconfig rejected: {}", e.getMessage(), e.getCause());
}

When it happens

Trigger: Calling DataNode.reconfigureProperty (via 'hdfs dfsadmin -reconfig datanode <dn:ipc> start', the Reconfiguration JMX bean, or the HTTP reconfig servlet) for dfs.datanode.peer.stats.enabled with values like "1", "yes", "on", "enabled", an empty string, " true" with leading/trailing whitespace, or an unexpanded template placeholder. A null newVal is accepted and resets to DFS_DATANODE_PEER_STATS_ENABLED_DEFAULT.

Common situations: Enabling slow-peer metrics on a live cluster using yes/no style booleans from internal wikis; Ambari/Cloudera Manager/Ansible templates that render booleans as 1/0 or pad whitespace; scripts that reuse client-side key names in datanode reconfig payloads.

Related errors

• Not a valid Boolean value for {property}
• No directory is specified.
• FsDatasetSpi has not been initialized
• Changing storage type is not allowed.
• Attempt to remove all volumes.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/b4fea0809861b51b. Report an issue: GitHub.