static String getInstanceName(DataNodeId dataNode) {
    return ClusterMapUtils.getInstanceName(dataNode.getHostname(), dataNode.getPort());
  }
Get the instance name string associated with this data node in Helix.
@param dataNode the {@link DataNodeId} of the data node.
@return the instance name string.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/HelixBootstrapUpgradeUtil.java