private String[] getNodes(String clusterName) {
        String s = conf.getProperty(CLUSTER_KEY + clusterName);
        if (s != null) {
            String[] n = s.split("\\s+");
            if (n.length < 1) {
                throw new IllegalArgumentException("No nodes in cluster " + clusterName);
            }
            return n;
        }
        throw new IllegalArgumentException("No such cluster '" + clusterName + "'");
    }