logger.debug("cluster state updated, version [{}], source [{}]", clusterState.version(), source);
}
ClusterChangedEvent clusterChangedEvent = new ClusterChangedEvent(source, clusterState, previousClusterState);
// new cluster state, notify all listeners
final DiscoveryNodes.Delta nodesDelta = clusterChangedEvent.nodesDelta();
if (nodesDelta.hasChanges() && logger.isInfoEnabled()) {
String summary = nodesDelta.shortSummary();
if (summary.length() > 0) {
logger.info("{}, reason: {}", summary, source);
}