config.cluster.php

<?php
/**
 * PHP version of the rewrite rules that were previously used to enable multi-site in a cluster environnement
 *
 * Each site has its own file, based on its vardir subcomponent: var/plain_site/ => config.cluster/plain_site.php.
 * The cluster rewrite rules send everything to index_cluster.php, for every site.
 **/
if ( !$siteId = preg_match( "|^/var/([^/]+)/|", $_SERVER['SCRIPT_URL'], $m ) )
    // error 404
    // exit

$configFile = "config.cluster/$siteId.php";
if ( !file_exists( $configFile ) )
    // error 404
    // exit

include $configFile;