Volt directory can't be written

Unless you specify a different folder for Volt to compile its templates, the folder where the view file is located will be used to create the relevant compiled file.

You can change this behavior by setting the proper option when you register your service as such:

use \Phalcon\Mvc\View as PhView;
use \Phalcon\Mvc\View\Engine\Volt as PhVolt;

...

public function initView($options = array())
{
    $config = $this->di['config'];
    $di     = $this->di;

    $this->di['volt'] = function ($view, $di) use ($config) {

        $volt = new PhVolt($view, $di);
        $volt->setOptions(
            array(
                'compiledPath'      => $config->app_volt->path,
                'compiledExtension' => $config->app_volt->extension,
                'compiledSeparator' => $config->app_volt->separator,
                'stat'              => (bool) $config->app_volt->stat,
            )
        );

        return $volt;
    };

    /**
     * Setup the view service
     */
    $this->di['view'] = function () use ($config, $di) {

        $view = new PhView();
        $view->setViewsDir($config->app_path->views);
        $view->registerEngines(array('.volt' => 'volt'));

        return $view;
    };
}

The $config will store all the information you need. By using the compiledPath you instruct Volt to compile the templates there and then serve them to the front end. That folder needs to be writeable for the user that runs your web server www-data or other and can be outside your public folder.

The file structure I usually use is:

app
    \controllers
    \models
    \views
public
    \js
    \css
    \img
var
    \volt
    \logs
    \config
    \cache

Change volt file permission (Inside app/cache) to 777 .Its working fine

Contrary to several of the other answers here, don't just willy-nilly set permissions to 0777 and pretend everything's okay, that's completely ridiculous. Your server needs to write to the volt folder inside your cache directory.

You might need to create the folder first. sudo mkdir cache, and sudo mkdir cache/volt. Then chown that folder with whatever is the username that your server runs.

NOTE: Depending on your configuration, the cache folder might be located at the project root and not inside app.

For example, if your server launches under the permissions of user named 'www-data' (which is most common), after creating the proper folder structure, the following command will fix your issue: sudo chown www-data:www-data -R cache