cluster.js

var cluster = require('cluster');
var numCPUs = require('os').cpus().length;

if (cluster.isMaster) {

    // Fork workers.
    for (var i = 0; i < numCPUs; i++) {
        cluster.fork();
    }

    cluster.on('fork', function(worker) {
        console.log('--- Cluster: worker ' + worker.process.pid + ' started');
    });
    cluster.on('exit', function(worker, code, signal) {
        console.log('--- Cluster: Worker ' + worker.process.pid + ' died (code: ' + code + '), restarting...');
        cluster.fork();
    });

} else {

    require('./server');

    if (CONFIG.CLUSTER_WORKER_RESTART_ON_MEMORY_USED) {
        setInterval(function() {

            var mem = process.memoryUsage().rss;
            if (mem > CONFIG.CLUSTER_WORKER_RESTART_ON_MEMORY_USED) {
                console.log('--- Cluster: worker ' + process.pid + ' used too much memory, exiting...');
                process.exit(1);
            }

        }, 1000);
    }
}