Yii2-maintenance

Installation

Add to the require section of your composer.json file:

"n1k88/yii2-maintenance-mode": "*"

Add to your config file:

   'bootstrap' => ['log', 'maintenance'],
   ...
   'modules' => [
     'maintenance' => [
        'class' => 'n1k88\maintenance\Module',
        // optional
        'maintenanceFileOn' => 'maintenance.on', // default is `maintenance.on`
     ],
   ],

Create a file in the @web directory named maintenance.on to activate the maintenance mode.