* so it can be reused.
*/
private void populateDatanodeMetrics(ArrayList<DatanodeDescriptor> live,
ArrayList<DatanodeDescriptor> dead) {
DatanodeStatus status = FSNamesystemDatanodeHelper.getDatanodeStats(fsNameSystem,
live, dead);
// populate metrics
numLiveNodes.set(status.numLive);
numLiveExcludedNodes.set(status.numLiveExcluded);