I'm posting this for anyone else who might run into this error message when installing Aegir:

installing the Aegir frontend (Drupal with the hostmaster profile), please wait...
PHP Fatal error: Out of memory (allocated 1616117760) (tried to allocate 1610352641 bytes) in /usr/share/drush/includes/drush.inc on line 1099

The install throws this error if you haven't correctly specified the "FQDN" (Fully Qualified Domain Name), what you need to do is make sure yourdomain.com is the only thing in /etc/hostname and also make sure /etc/hosts contains:
127.0.0.1 yourdomain.com

After doing this restart the hostname service with :
start hostname