@Override
  public void unlock() {

    if (nodePath != null) {
      zkUtils.getZkClient().delete(nodePath);
      nodePath = null;
      LOG.info("Ephemeral lock node deleted. Unlocked!");
    } else {
      LOG.warn("Ephemeral lock node you want to delete doesn't exist");
    }
  }
Unlocks, by deleting the ephemeral sequential node created to acquire the lock.
samza-core/src/main/java/org/apache/samza/zk/ZkDistributedLock.java