Scalr\System\Zmq\Cron\Launcher::ensureBrokerRunning PHP Method

    public static function ensureBrokerRunning()
    {
        $client = (new Client(\Scalr::config('scalr.crontab.sockets.broker')))->setTimeout(100)->setRetries(1)->setLogger(\Scalr::getContainer()->logger('Mdp\\Client')->setLevel(\Scalr::config('scalr.crontab.log_level')))->connect();
        $mmiReq = new Zmsg();
        $mmiReq->push("system.healthcheck");
        $mmiRep = $client->send("mmi.service", $mmiReq);
        if ($mmiRep) {
            $ok = $mmiRep->pop();
        } else {
            $ok = false;
            //Make sure another broker process isn't hanging
            self::terminateBroker();
            //Broker has to be started in the separate process
            $op = [];
            $logFile = \Scalr::config('scalr.crontab.log');
            exec(self::getStartBrokerCommand() . ' ' . ($logFile == '/dev/null' ? '> ' : '>> ') . escapeshellcmd($logFile) . ' 2>&1 & echo $!', $op);
            $pid = intval($op[0]);
        }
        return $ok;
    }