apache/iceberg · warning

Failed to close ZkLockFactory for lockId

Error message

Failed to close ZkLockFactory for lockId: {}

What it means

ZkLockFactory.closeQuietly is called from open() when initialization partially fails: it attempts close() and, if closing the ZooKeeper-based lock factory throws, logs this warning with the lockId instead of propagating. The original failure that triggered the cleanup remains the primary error; this warning only reports that resource cleanup also failed.

Solutions

1. Find and fix the original exception that caused open() to fail (usually a ZooKeeper connectivity or configuration problem).
2. Verify ZooKeeper connect string, session timeout, and that the ZK ensemble is reachable from the Flink cluster.
3. Ensure the Curator client is not closed twice (check lifecycle management of ZkLockFactory in the maintenance job).

Example fix

// before
lockFactoryBuilder = ZkLockFactory.builder()
    .setZkServers("wrong-host:2181")
    .setLockId("maintenance");

// after
lockFactoryBuilder = ZkLockFactory.builder()
    .setZkServers("zk1:2181,zk2:2181,zk3:2181")
    .setLockId("maintenance");

// Pre-flight: confirm ZK reachable before opening the factory
try (Socket s = new Socket()) {
  s.connect(new InetSocketAddress(zkHost, zkPort), 5000);
}

try {
  lockFactory.open();
} catch (Exception e) {
  LOG.error("ZkLockFactory init failed (see also 'Failed to close ZkLockFactory' if cleanup also failed)", e);
  throw e;
}

When it happens

Trigger: ZkLockFactory.open() (or initialization) fails partway and calls closeQuietly(); close() throws (e.g. Curator/ZooKeeper client already closed or connection broken), producing this warning.

Common situations: ZooKeeper unreachable at startup so factory init fails and cleanup also throws; double-close of the Curator framework client; timeout during shutdown.

Related errors

• Failed to close ZkLockFactory for lockId
• Connection to Zookeeper timed out
• Connection to Zookeeper timed out
• Failed to acquire Zookeeper lock
• Failed to acquire Zookeeper lock

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/ba185fb434799357. Report an issue: GitHub.

Appendix: source

Thrown at flink/v2.2/flink/src/main/java/org/apache/iceberg/flink/maintenance/api/ZkLockFactory.java:156

    } catch (Exception e) {
      closeQuietly();
      throw new RuntimeException("Failed to initialize SharedCount", e);
    }
  }

  private String getTaskSharePath() {
    return LOCK_BASE_PATH + lockId + "/task";
  }

  private String getRecoverySharedPath() {
    return LOCK_BASE_PATH + lockId + "/recovery";
  }

  private void closeQuietly() {
    try {
      close();
    } catch (Exception e) {
      LOG.warn("Failed to close ZkLockFactory for lockId: {}", lockId, e);
    }
  }

  @Override
  public Lock createLock() {
    return new ZkLock(getTaskSharePath(), taskSharedCount);
  }

  @Override
  public Lock createRecoveryLock() {
    return new ZkLock(getRecoverySharedPath(), recoverySharedCount);
  }

  @Override
  public void close() throws IOException {
    try {
      if (taskSharedCount != null) {
        taskSharedCount.close();

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