Drupal depends on a cron system to execute period tasks in Drupal. This cron system in turn expects a call to the cron.php file from a client either as a Drupal shell request or as an http request to the Drupal site. The following outlines how to set up a cron job in an Amazon AWS server set up using the bitnami stack.
Amazon AWS
Some times we need to protect our site from public users and make it available only to selected number of users. For examply you might want to protect your alpha site from the public and from search engine bots. In such situations we protect our site with HTTP password. Follow the below steps for protecting your Drupal site with HTTP password. This was written for an Amazon AWS server but should work on most GNU/Linux servers.