Trigger cron internally using PHP The server my site is on cannot use curl, wget or lynx to call the external cron address (eg http://example.com/cron/cron_key)

Is it possible to use php to 'run' the cron from inside the server. 

I'm was thinking something like php -f /home/docroot/core/Drupal/Cron.php with a query string for the cron key, but I notice there isn't a query string as in Drupal 7. 

I cannot use Drush since it's not installed on the prod servers. 

I also cannot use a third party external cron service. 

Any ideas?
a way to do that :

create customcron.php in the drupal root with the content :

&lt;?php

use Drupal\Core\DrupalKernel;
use Symfony\Component\HttpFoundation\Request;

$autoloader = require_once 'autoload.php';

$kernel = new DrupalKernel('prod', $autoloader);

$request = Request::createFromGlobals();
$response = $kernel-&gt;handle($request);

// Load cron service and run cron.
\Drupal::service('cron')-&gt;run();

$kernel-&gt;terminate($request, $response);


then run :

php customcron.php


i would not let the file customcron.php in the root because anybody could then execute it from the browser.

A simple way to avoid that is moving the file customcron.php to drupal root only for the time you execute it or maybe have an unguessable file name instead of customcron.php