The goal is to run 2 rails app at:

Before we start, you can setup your first app like usual. I will skip the steps. If you do not understand, you can refer here for more information.

To setup your second app, follow the same steps as the usual setup. The only difference is the configuration in the server block. Instead of following the usual steps, you need to modify your Nginx server block and add these code below into it.

server {
        ### Other Codes 
        passenger_enabled on;
        rails_env production;
        root /path/to/first_app/public;

        ### Add this: Handling another app
        location ~ ^/another_app(/.*|$) {
                alias /path/to/another_app/public$1; # Point to public folder, note the $1 behind.
                passenger_base_uri /another_app;
                passenger_app_root /path/to/another_app;
                passenger_document_root /path/to/another_app/public;
                passenger_enabled on;
        ### Other Codes

Add the following config in your rails app:

config.action_controller.relative_url_root = '/another_app'

Then, restart your Nginx server and that's it.