脚本作用：持续ping该类服务器，保证中转路由能在业务使用时能够快速响应请求。

    <?php  
    define('LOGTAG', 'ping');  
    declare(ticks = 1);  
    $pid_arr = array();  
    pcntl_signal(SIGQUIT, 'signal_handler');  
    pcntl_signal(SIGTERM, 'signal_handler');  
      
    function run($servers_info)   
    {  
        echo "---------- ping task begin ----------";  
        global $pid_arr;  
        $index=0;  
        $name_arr = array();  
        $ip_arr = array();  
        foreach( $servers_info as $val) {  
            $name_arr[$index] = $val['server_name'];  
            $ip_arr[$index] = $val['server_ip'];  
            $index++;  
        }  
        $worker_count = $index;  
        $index=0;  
        while($index < $worker_count)   
        {  
            $pid = pcntl_fork();  
            if($pid == -1) {  
                die('could not fork');  
            }   
            else   
            {  
                if($pid) {  
                    $pid_arr[$index] = $pid;  
                } else {  
                    while(true) {  
                        handle($name_arr[$index], $ip_arr[$index]);  
                        sleep(1);  
                    }  
                }  
            }  
            $index++;  
        }  
        while (true) {  
            sleep(1);  
        }  
    }  
      
    function handle($name,$ip) {  
        echo "ping ".$name." ip:".$ip." start!";  
        exec("ping -c 1000 $ip",$list);  
        echo "ping ".$name." ip:".$ip." finish!";  
    }  
      
    function signal_handler($signal) {  
        global $pid_arr;  
        if ($signal == SIGQUIT || $signal == SIGTERM)   
        {  
            foreach ($pid_arr as $pid) {  
                posix_kill($pid,SIGTERM);  
            }  
            echo ”————— ping task finish ----------";  
            exit();  
        }  
    }  
      
    run();  
    ?>