private static int groupsAdjustedForRedundancy(int nodes, int groups) {
        return nodes > 1 ? (groups == 1 ? 1 : groups - 1) : groups;
    }
The number of groups this cluster has, or will have if not deployed yet.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ClusterModel.java