create an ssh class for maintaining a pool of ssh connections and running commands on them in parallel via a queue

class ssh {

  private $pool = array();
  private $queue = array();
  
  public function add($host, $user, $pass) {
    $ssh = new Net_SSH2($host);
    if (!$ssh->login($user, $pass)) {
      exit('Login Failed');
    }
    
    $this->pool[] = $ssh;
  }
  
  public function exec($cmd) {
    $this->queue[] = $cmd;
  }
  
  public function run() {
    $pool = $this->pool;
    $queue = $this->queue;
    
    while (count($pool) && count($queue)) {
      foreach ($pool as $key => $ssh) {
        $cmd = array_shift($queue);
        $ssh->exec($cmd);
        unset($pool[$key]);
      }
    }
  }

}

$ssh = new ssh;
$ssh->add('1.1.1.1', 'user', 'pass');
$ssh