Konstantin Tutsch

A single webserver serving multiple domains

My setup and the importance to me

So, I'm pretty sure that an introduction is always helpful.

I've a got Raspberry Pi, 8G memory and 4 cores @ 1.8GHz, running at home. It was used for only a single service with a web interface.

I always wanted to use my Raspberry Pi for more, but only if the services looked "normal" from the outside, that is: no special ports needed to access them, just a simple subdomain.

My (not so) special discovery

What I realized wasn't that surprising after all. I saw a video about a homeserver and that all the services had their own local domains. But how?

That isn't different from domain names on the internet. So I must be able to reproduce it and my "selfhosting dream" would come true!

I remembered that a webserver also knows which domain the client accessed / typed into the URL bar. A quick search, about how the Nginx webserver handles such, gave me the solution: in an Nginx configuration file for a site, you always specify the server_name parameter with the hosts' domain.

But if I point two domains, lets just say example1.com and example2.com to my Raspberry Pi, creating two server {}s with different values in the server_name but listening on the same port, each of those domains would get it's own unique website.

This is how it could look like. Each configuration has their respective site.

example1.com

server {
  listen 443 ssl;
  listen [::]:443 ssl;
  server_name example1.com;

  ssl_certificate /etc/letsencrypt/live/example1.com/fullchain.pem; # managed by Certbot
  ssl_certificate_key /etc/letsencrypt/live/example1.com/privkey.pem; # managed by Certbot
  include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
  ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

  location / {
    proxy_pass https://127.0.0.1:59000;
  }
}

server {
  listen 80;
  listen [::]:80;
  server_name example1.com;

  if ($host = example1.com) {
    return 301 https://$host$request_uri;
  } # managed by Certbot

  return 404; # managed by Certbot
}

example2.com

server {
  listen 443 ssl;
  listen [::]:443 ssl;
  server_name example2.com;

  ssl_certificate /etc/letsencrypt/live/example2.com/fullchain.pem; # managed by Certbot
  ssl_certificate_key /etc/letsencrypt/live/example2.com/privkey.pem; # managed by Certbot
  include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
  ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

  location / {
    proxy_pass https://127.0.0.1:60000;
  }
}

server {
  listen 80;
  listen [::]:80;
  server_name example2.com;

  if ($host = example2.com) {
    return 301 https://$host$request_uri;
  } # managed by Certbot

  return 404; # managed by Certbot
}

Conclusion

That's it, a really handy trick to save money and host multiple services on a single system.

This, of course, only works with web apps. If your app isn't web-based, then you should look into SRV records. But they only work with applications and protocols who intend to use them.

Hope you enjoyed reading this post and that the information from here helps you at some point somewhere 😄