public boolean hasId() {
    return getId() != null;
  }
Publishes and synchronizes a unique identifier specific to a given HBase cluster. The stored
identifier is read from the file system by the active master on startup, and is subsequently
available to all watchers (including clients).
hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKClusterId.java