Overview
An application launched by Passenger may be restarted by creating a file in tmp/ (NB: not /tmp) within the application root directory, usually one level down from public/. Create a file under tmp/ named restart.txt to restart the application once. A restart will happen within 2 minutes.
To restart an application on every request, very useful for in-place debugging, create a file named always_restart.txt.
Note: do not leave always_restart.txt file for an application in production. This results in very poor performance.