public void getConfig(StorDistributionConfig.Group.Builder builder) {
        builder.index(index == null ? "invalid" : index);
        builder.name(name == null ? "invalid" : name);
        partitions.ifPresent(builder::partitions);
        for (StorageNode node : nodes) {
            StorDistributionConfig.Group.Nodes.Builder nb = new StorDistributionConfig.Group.Nodes.Builder();
            nb.index(node.getDistributionKey());
            nb.retired(node.isRetired());
            builder.nodes.add(nb);
        }
        builder.capacity(getCapacity());
    }
Returns all the nodes below this group
config-model/src/main/java/com/yahoo/vespa/model/content/StorageGroup.java