private static String hostnamesAsString(List<Node> nodes) {
        if (nodes.isEmpty()) return "none";
        return nodes.stream().map(Node::hostname).sorted().collect(Collectors.joining(", "));
    }
Returns true if the peer is a tenant host or node.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiHandler.java