Introduction to Tools and Techniques in Computer Science

Configure and run a web server

Franklin Bristow

One very popular use for Linux is to run web servers. A web server is a program that runs on a computer, waiting for requests to come from (for example) web browsers, and sending back a response so your web browser can (for example) show you videos of cats.

The first part of this is installing a web server. There are three popular web servers:

  1. Apache HTTPD
  2. NGINX (pronounced like “engine-X”)
  3. Caddy

Installing Caddy

Caddy can be installed using apt, but you need to do a little bit of extra set up — Caddy’s packages are not in the Ubuntu repositories. Instead, Caddy hosts its own repositories, and you can add that repository to the set of repositories apt can download from on your system.

The Caddy documentation describes what commands you should run, you can run these commands in your terminal in your Linux system. One addition to the Caddy documentation is that you may need to install curl before following their guide:

sudo apt install curl

After you’ve followed the steps in the documentation, Caddy should be running! Open the web browser in your Linux system and browse to http://localhost.

Configuring Caddy

Now that Caddy’s installed, let’s get it set up so that the server is serving what we want instead of the default.

Almost everything in this section is very specific to Caddy and isn’t really transferable anywhere else. Configuration files, locations, and what web servers can do depends entirely on the web server, so what we do here will not in any way apply to NGINX or Apache HTTPD.

Serve a static string:

  • Edit the file /etc/caddy/Caddyfile as root:

    sudo vim /etc/caddy/Caddyfile

  • Comment out everything inside the block :80 {}

  • Add respond "Hello, world!" inside the block.

  • Restart Caddy so that it starts up with the changes you made.

    sudo systemctl restart caddy

  • Open the web browser in your Linux system and navigate to http://localhost

  • 👋

Serve a static file:

  • Edit the file /etc/caddy/Caddyfile as root.

  • Uncomment the lines you commented out.

  • Comment out the respond line you added.

  • Restart caddy.

  • Replace /usr/share/caddy/index.html with your own index.html (maybe by converting a Markdown file to HTML, you did this in reading and changing permissions). Your user account does not have permissions to write to this directory, so you can mv or cp the file with sudo:

    sudo mv index.html /usr/share/caddy/

  • Refresh your web browser.

  • 🎉

Further reading

Installing a web server inside your Linux install is great, but its use for now is limited to the web browser inside your Linux install.

Your next steps are to install Caddy on (for example) a virtual machine that you’ve created on Azure, buy yourself a domain name, and have your own personal web page running on Linux by following some more documentation on the Caddy website.

If you’re running your Linux install in a VM, you can configure “port forwarding” so that you can connect to your web server from the web browser installed on your host system, or SSH to your virtual machine.