public List<String> getAllDataNodeNames() {
    List<String> names = propertyStore.getChildNames(CONFIG_PATH, AccessOption.PERSISTENT);
    return names == null ? Collections.emptyList() : names;
  }
@return all data node names in the property store.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/PropertyStoreToDataNodeConfigAdapter.java