ASP.NET Core on Debian and Apache

2018-01-11 2023-11-22

Now that Microsoft has created .NET Core it should be possible to host a .NET website on Linux. Specifically I want to host an ASP.NET Core 8.0 website on .NET 8.0 on Debian 12 (bookworm) with Apache 2.

Install .NET Core

.NET is not part of Debian. It must be installed from Microsoft's package feed, which is added by creating the following file:

/etc/apt/sources.list.d/microsoft.list

deb [arch=amd64] https://packages.microsoft.com/debian/12/prod bookworm main

We also need the Microsoft package key to validate packages. This must be downloaded and installed in the correct place.

wget https://packages.microsoft.com/keys/microsoft.asc
sudo mv microsoft.asc /etc/apt/trusted.gpg.d/

Now we should be able to install the ASP.NET Core Runtime. This will also install the .NET Runtime.

sudo apt-get update
sudo apt-get install aspnetcore-runtime-8.0

If successful the following command should display the versions for both ASP.NET Core and .NET:

dotnet --list-runtimes

Create website

I prefer to develop my web sites in Visual Studio on Windows. Visual Studio Code can be used if you want to develop under Linux.

The web site should be an ASP.NET Core Web Application for .NET Core and ASP.NET Core 2.0. I will call this web site DotnetExampleSite because it's clever.

Publish the site to some directory on the Debian machine. I will use /srv/www/DotnetExampleSite.

Configure Kestrel

The way ASP.NET Core works is that each web application runs its own instance of a web server called Kestrel. By default Kestrel will listen on port 5000.

To make Kestrel and our web application run we must create a systemd service. Create the following file:

/etc/systemd/system/dotnet-example-site.service

[Unit]
Description=.NET Example Site
After=network.target

[Service]
WorkingDirectory=/srv/www/DotnetExampleSite
ExecStart=/usr/bin/dotnet /srv/www/DotnetExampleSite/DotnetExampleSite.dll
Restart=always
RestartSec=10
SyslogIdentifier=dotnet-example-site
User=www-data
Environment=ASPNETCORE_ENVIRONMENT=Production

[Install]
WantedBy=multi-user.target

As can be seen above we will run the Kestrel web server under the www-data user. This makes sense and will work well when we configure Apache next.

Before we can run the web application we need to create a directory that ASP.NET Core will use for some housekeeping.

sudo mkdir /var/www/.dotnet
sudo chown www-data:www-data /var/www/.dotnet

Now we shuould be able to run the service.

sudo systemctl start dotnet-example-site

If everything works you should now be able to view the site on port 5000.

curl http://localhost:5000

Another command is necessary in order to start the service at boot.

sudo systemctl enable dotnet-example-site

Configure Apache

We could stop here. But Kestrel is a very limited web server and not intended to be exposed to the Internet. Instead it is recommended to run a more competent web server before it as a proxy. On Windows this would be IIS. On Linux is often nginx. But I will use Apache.

Begin by enabling the Apache 2 proxy modules for HTTP.

sudo a2enmod proxy
sudo a2enmod proxy_http

Then create the following file:

/etc/apache2/sites-available/dotnet-example-site.conf

<VirtualHost *:80>
    ServerName dotnet.localtest.me

    ProxyPreserveHost On
    ProxyPass / http://localhost:5000/
    ProxyPassReverse / http://localhost:5000/
</VirtualHost>

Finally enable the new web site configuration.

sudo a2ensite dotnet-example-site

Now, if everything works, we should be able to navigate to the site.

curl http://dotnet.localtest.me