public function indexAction()
    {
        // Get all instances
        $instances = $this->getManager()->findAll();
        
        $worker = $this->get('ringo_php_redmon.instance_worker');
        if(is_array($instances)) {
            foreach($instances as $index => $instance) {
                // Ping server and get potential error message
                $working = $worker->setInstance($instance)->ping();
                $instances[$index]->setWorking($working);
                $instances[$index]->setError($worker->getMessage());
            }
        }
        
        return $this->render(
            $this->getTemplatePath().'index.html.twig',
            array(
                'instances' => $instances 
            )
        );
    }