How to Set Up Multiple Websites under One IP Address with Apache and .Net

INTRODUCTION

Running multiple web applications under your cable modem is virtually free and awesome.  You can get domains for a couple of bucks, security certificates are free, and you can keep it all nested under a Virtual Box virtual machine to protect your home network.  With today's single page app frameworks like via React or Blazor, the traffic is very low for a small business or a hobby.  You won't even notice it while watching Netflix and your kids are streaming their games in the other room.  

WORKFLOW

Here is how to install a web app.  It is similar on a Windows machine, but this is a Linux example. You do step 3 and beyond for each domain you want to build.

1. Buy a domain name: Premium DNS hosting plans. Test for Free | ClouDNS
2. Install the latest .Net.  This example is for 7.0: 

wget https://packages.microsoft.com/config/debian/11/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
sudo dpkg -i packages-microsoft-prod.deb
rm packages-microsoft-prod.deb

sudo apt-get update && \
  sudo apt-get install -y dotnet-sdk-7.0

3. Make an example app with dotnet:

dotnet new blazorserver -o myapp

4.  Add your custom port to the application.json (the ports must be different for all your apps):

"Kestrel": {
    "Endpoints": {
      "Https": {
        "Url": "http://127.0.0.1:5003"
      },
      "Http": {
        "Url": "http://127.0.0.1:5002"
      }
    }
  }

5. Make the app run as a service by editing a service text file:

#save this as  /etc/systemd/system/kestrel-myapp.service 
[Unit]
Description=myapp

[Service]
WorkingDirectory=/var/www/myapp
ExecStart=dotnet /var/www/myapp/myapp.dll
Restart=always
# Restart service after 10 seconds if the dotnet service crashes:
RestartSec=10
KillSignal=SIGINT
SyslogIdentifier=myapp
User=root
Environment=ASPNETCORE_ENVIRONMENT=Production

[Install]
WantedBy=multi-user.target

6. Publish your app with dotnet.  I write a script to do it for mine and simply execute the script.  Here is my script that I name "m" and chmod +X to quickly publish:

sudo systemctl stop kestrel-myapp
sudo dotnet publish -o /var/www/myapp
sudo systemctl start kestrel-myapp

7. Edit your Apache site config file:

# this is probably located under /etc/apache2/sites-enabled/000-default.conf
<VirtualHost *:80>
   ServerName mysite.com
   ServerAlias www.mysite.com
   ProxyPreserveHost On
   ProxyPass /  http://127.0.0.1:5002/
   ProxyPassReverse /  http://127.0.0.1:5002/

   ErrorLog ${APACHE_LOG_DIR}/error.log
   CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

8. Get a free TSL (aka SSL) certificate from Let's Encrypt and Install it with Certbot.  This will help somewhat: Tutorial: Configure SSL/TLS on Amazon Linux 2 - Amazon Elastic Compute Cloud.

USEFUL COMMANDS

sudo systemctl restart apache2 #used after changing Virtual Host config files

sudo journalctl -u kestrel-myapp.service #used to look at errors of your app service if it isn't working

sudo systemctl status kestrel-myapp.service #used to see if your app service is running

sudo systemctl daemon-reload #used after changing a service config file

CONCLUSION

Seeing it all written out, it all makes perfect sense: 1) install the app framework, 2) run it as a service, 3) configure the web server to route traffic.  However, having it written out will ensure you don't get so frustrated when you do it that you give up.  I hope others find this helpful.

-Sean