default Set<Node> nodes() {
        return groups().stream().flatMap(group -> group.nodes().stream())
                       .sorted(comparingInt(Node::key))
                       .collect(toCollection(LinkedHashSet::new));
    }
Simple interface for groups and their nodes in the content cluster.

@author baldersheim
container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/SearchGroups.java