How to Install Caddy Web Server on Ubuntu 20.04

Caddy is an open-source web server that supports both static and modern web applications, with automatic HTTPS enabled for all linked domain names. Written in GO, Caddy provides user-friendly configuration directives, allowing it to function as a web server, reverse proxy, or load balancer to serve web applications on your server.

This article guides you through the process of installing Caddy on Ubuntu 20.04 and securely serving web applications.

Prerequisites

Before you begin:

• Have an Ubuntu 20.04 server.

• Set up a new A record for your domain that points to the server IP address.

• Access the server using SSH as a non-root user with sudo privileges.

Install Caddy

Caddy is not included in the default Ubuntu 20.04 APT repositories. However, it can be installed either from source files or by adding the latest repository information to your server. Follow the steps below to download the latest Caddy repository details and install the application on your server.

1. Add the latest Caddy GPG Key to your server.

   CONSOLE

   Copy

   $ curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg

   Explain Code

   Powered by Vultr AgentBeta

2. Add the Caddy repository to your APT sources.

   CONSOLE

   Copy

   $ curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-stable.list

   Explain Code

   Powered by Vultr AgentBeta

3. Update the server package index.

   CONSOLE

   Copy

   $ sudo apt update

   Explain Code

   Powered by Vultr AgentBeta

4. Install Caddy.

   CONSOLE

   Copy

   $ sudo apt install caddy

   Explain Code

   Powered by Vultr AgentBeta

5. View the installed Caddy version to verify that the installation is successful.

   CONSOLE

   Copy

   $ caddy -v

   Explain Code

   Powered by Vultr AgentBeta

   Output:

   v2.9.1 h1:OEYiZ7DbCzAWVb6TNEkjRcSCRGHVoZsJinoDR/n9oaY=

6. Allow incoming connections to the HTTP port 80 through the firewall.

   CONSOLE

   Copy

   $ sudo ufw allow 80

   Explain Code

   Powered by Vultr AgentBeta

7. Restart the firewall to apply changes.

   CONSOLE

   Copy

   $ sudo ufw reload

   Explain Code

   Powered by Vultr AgentBeta

8. Access your server IP to test access to the Caddy web server.

   http://SERVER-IP

   Confirm that the default Caddy webpage displays in your browser.

   

Manage the Caddy System Service

1. Enable Caddy to start at boot time.

   CONSOLE

   Copy

   $ sudo systemctl enable caddy

   Explain Code

   Powered by Vultr AgentBeta

2. Start the Caddy web server.

   CONSOLE

   Copy

   $ sudo systemctl start caddy

   Explain Code

   Powered by Vultr AgentBeta

3. View the Caddy system service status to verify that the application is running.

   CONSOLE

   Copy

   $ sudo systemctl status caddy

   Explain Code

   Powered by Vultr AgentBeta

   Output:

   ● caddy.service - Caddy
        Loaded: loaded (/lib/systemd/system/caddy.service; enabled; vendor preset: enabled)
        Active: active (running) since Sun 2025-04-06 09:20:18 UTC; 4min 10s ago
          Docs: https://caddyserver.com/docs/
      Main PID: 3015 (caddy)
         Tasks: 9 (limit: 9415)
        Memory: 10.9M
        CGroup: /system.slice/caddy.service
                └─3015 /usr/bin/caddy run --environ --config /etc/caddy/Caddyfile

Create a Caddy Virtual Host

Caddy stores its configuration files in the /etc/caddy directory by default and allows Caddyfile configurations from any location on your server. Follow the steps below to create a new Caddy virtual host to serve web application files from the /var/www/example.com directory on your server.

1. Create the /var/www/example.com web application files directory.

   CONSOLE

   Copy

   $ sudo mkdir -p /var/www/example.com

   Explain Code

   Powered by Vultr AgentBeta

2. Create a new HTML application file index.html.

   CONSOLE

   Copy

   $ sudo nano /var/www/example.com/index.html

   Explain Code

   Powered by Vultr AgentBeta

3. Add the following code to the file.

   HTML

   Copy

   <!DOCTYPE html>
   <html>
   <head>
       <meta charset="UTF-8">
       <title>Greetings from Vultr!</title>
   </head>
   <body>
       <br><br><br>
       <h1 style="text-align: center;">Hello World! Greetings from Vultr</h1>
   </body>
   </html>

   Explain Code

   Powered by Vultr AgentBeta

   Save and close the file.

4. Switch to the Caddy configuration files directory.

   CONSOLE

   Copy

   $ cd /etc/caddy/

   Explain Code

   Powered by Vultr AgentBeta

5. Back up the default Caddyfile configuration.

   CONSOLE

   Copy

   $ sudo mv Caddyfile Caddyfile.default

   Explain Code

   Powered by Vultr AgentBeta

6. Create a new Caddyfile configuration.

   CONSOLE

   Copy

   $ sudo nano Caddyfile

   Explain Code

   Powered by Vultr AgentBeta

7. Add the following configurations to the file.

   INI

   Copy

   example.com {
           tls admin@example.com
   
           root * /var/www/example.com
   
           file_server {
                   index index.html
           }
   
           log {
                   output file /var/log/caddy/example.log
                   format console
           }
   }

   Explain Code

   Powered by Vultr AgentBeta

   Save and exit the file.

   The Caddy configuration above creates a new virtual host for your domain example.com. Here’s what each part does:

   • example.com: Defines a new virtual host profile using your domain or IP address.
   • tls: Associates an email address with Let's Encrypt for SSL certificate generation requests.
   • root: Specifies the directory containing the web application files for the virtual host.
   • file_server: Enables the file server for serving web application files. The index directive sets the default file to be served when accessing your domain.
   • log: Configures logging for access and error details to a specified file, such as /var/log/caddy/example.log.

8. Test the Caddy configuration for errors.

   CONSOLE

   Copy

   $ sudo caddy validate

   Explain Code

   Powered by Vultr AgentBeta

   Output:

   ...........
   2024/06/1 15:19:11.478 INFO    tls.cache.maintenance   started background certificate maintenance      {"cache": "0xc0000e5300"}
   2024/06/1 15:19:11.478 INFO    tls.cache.maintenance   stopped background certificate maintenance      {"cache": "0xc0000e5300"}
   Valid configuration

9. Reload the Caddy web server to apply your configuration changes.

   CONSOLE

   Copy

   $ sudo caddy reload

   Explain Code

   Powered by Vultr AgentBeta

Secure the Caddy Web Server

Caddy automatically enables HTTPS to secure all connections using SSL certificates for virtual host profiles with valid domains on your server. Follow the steps below to secure the Caddy web server by restricting access to the Caddyfile configurations and preventing unauthorized changes by unintended users.

1. Grant the Caddy user full privileges to the /etc/caddy directory.

   CONSOLE

   Copy

   $ sudo chown -R caddy:caddy /etc/caddy

   Explain Code

   Powered by Vultr AgentBeta

2. Grant the Caddy user read and write permissions to the Caddyfile while disabling access for other system users.

   CONSOLE

   Copy

   $ sudo chmod 660 /etc/caddy/Caddyfile

   Explain Code

   Powered by Vultr AgentBeta

3. Long list the /etc/caddy directory to verify the permission changes.

   CONSOLE

   Copy

   $ ls -l /etc/caddy/

   Explain Code

   Powered by Vultr AgentBeta

   Output:

   total 8
   -rw-rw---- 1 caddy caddy 168 Jun 2 15:20 Caddyfile
   -rw-r--r-- 1 caddy caddy 769 Jun  2 12:07 Caddyfle.default

Set Up Firewall Rules

Caddy uses HTTP port 80 and HTTPS port 443, depending on your Caddyfile configurations, to serve files on the server. Follow the steps below to allow access to both Caddy ports through the firewall and enable network connections to the web server.

1. View the UFW status and verify that it's active.

   CONSOLE

   Copy

   $ sudo ufw status

   Explain Code

   Powered by Vultr AgentBeta

   If the status is inactive, allow the SSH port 22 and enable UFW.

   CONSOLE

   Copy

   $ sudo ufw allow 22 && sudo ufw enable

   Explain Code

   Powered by Vultr AgentBeta

2. Allow incoming connections to the HTTPS port 443.

   CONSOLE

   Copy

   $ sudo ufw allow 443

   Explain Code

   Powered by Vultr AgentBeta

3. Reload the firewall to apply changes

   CONSOLE

   Copy

   $ sudo ufw reload

   Explain Code

   Powered by Vultr AgentBeta

4. Access your domain using a browser such as Chrome to verify that Caddy serves your virtual host web application files.

   https://example.com

   If you receive a connection error, view the Caddy configuration logs to verify the error details.

   

Conclusion

You have successfully installed the Caddy web server on your Ubuntu 20.04 server and configured a virtual host profile to serve web application files.