@Override
      public void onDataNodeConfigChange(Iterable<DataNodeConfig> configs) {
        clusterChangeHandler.handleDataNodeConfigChange(configs, dcName, clusterMapConfig.clusterMapClusterName);
      }
Register for data node configs from Helix Property store.
@param dcName data center for which we are interested in data node configs.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/HelixAggregatedViewClusterInitializer.java