From OCS Support Wiki

Introduction

This guide will show you how to restart your Rails application running with Passenger (mod_passenger). It covers both the recommended way and the more brute-force method should that fail.

You will need to restart your application should you make any changes to it.

Recommend Method

Create a file called restart.txt in the tmp folder of your Rails application. You can do this via FTP, via the control panel, or in SSH by running:

touch ~/rails_apps/yourapp/tmp/restart.txt

You may need to change the path above to the location that your Rails application is.

Brute Force Method

Should the above method fail, you can connect via SSH and run:

ps ux

This will give you a list of your processes. Note the PID (Process ID) and run:

kill -9 PID

Replacing PID with the process ID obtained by running the previous command.