How to Install Caddy Webserver on Rocky Linux 9

Introduction

Caddy is an open-source webserver for developing and delivering static web applications. The webserver supports HTTP/3 and automatic SSL termination. Caddy also works as a reverse proxy or a load balancer that forwards HTTP client requests to backend services. You can also install Caddy plugins to extend the webserver's functionalities.

This article explains how to install the Caddy webserver on Rocky Linux 9.

Prerequisites

• Deploy a Rocky Linux 9 Cloud Compute instance on Vultr.
• Set up a domain A record pointing to the instance's public IP address. For example, app.example.com.
• Access the instance using SSH as a non-root user with sudo privileges.
• Update the instance.

Install Caddy

Caddy is available in the Extra Packages for Enterprise Linux (EPEL) repository on Rocky Linux 9 but the version might be outdated. Follow the steps below to install the webserver from the Caddy Community Projects (COPR) repository.

1. Install the DNF Copr Plugin.

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   $ sudo dnf install 'dnf-command(copr)'

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2. Enable the Caddy COPR repository.

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   $ sudo dnf copr enable @caddy/caddy

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   Enter Y when prompted to add the repository on your server.

3. Install Caddy.

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   $ sudo dnf -y install caddy

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4. View the Caddy version on your server.

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   $ caddy -v

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   Your output should be similar to the one below.

   v2.8.4 h1:q3pe0wpBj1OcHFZ3n/1nl4V4bxBrYoSoab7rL9BMYNk=

5. Allow Caddy HTTP port 80 through the firewall.

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   $ sudo firewall-cmd --permanent --zone=public --add-service=http

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6. Reload the firewall to apply changes.

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   $ sudo firewall-cmd --reload

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Manage the Caddy System Service

The caddy.service system service manages and controls the Caddy processes on your server. Follow the steps below to enable the service to automatically start at boot and manage the Caddy processes.

1. Enable the Caddy service to automatically start at boot.

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   $ sudo systemctl enable caddy

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2. Start the Caddy service.

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   $ sudo systemctl start caddy

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3. View the Caddy service status and verify that it's running.

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   $ sudo systemctl status caddy

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   Output:

   ● caddy.service - Caddy
    Loaded: loaded (/usr/lib/systemd/system/caddy.service; enabled; preset: disabled)
    Active: active (running) since Mon 2024-07-22 06:45:49 UTC; 1 week 0 days ago
      Docs: https://caddyserver.com/docs/
   Main PID: 59399 (caddy)
     Tasks: 7 (limit: 4632)
    Memory: 22.8M
       CPU: 18.830s
    CGroup: /system.slice/caddy.service
            └─59399 /usr/bin/caddy run --environ --config /etc/caddy/Caddyfile

4. Open a browser such as Firefox and access your server's public IP address.

   http://192.0.2.1

   Caddy should now display the default web application page.

   

Create a New Caddy Virtual Host

Caddy stores configurations for virtual hosts under the /etc/caddy directory. It supports virtual host configurations via Caddyfile from any location on your server. Follow the steps below to create a new Caddy virtual host to serve the website from the /var/www/app.example.com/html directory.

1. Create a new virtual host web root directory. For instance, /var/www/app.example.com/html.

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

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2. Use a text editor like Nano to create a sample index.html file under the new directory.

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

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3. Add the following contents to the index.html file.

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   <html>
       <head>
           <title>Caddy Server Install Test</title>
       </head>
       <body>
           <h1>Greetings from Vultr!</h1>
       </body>
   </html>

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   Save and close the file.

4. Create a new /etc/caddy/hosts directory to store the Caddy virtual host configuration files.

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   $ sudo mkdir /etc/caddy/hosts

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5. Open /etc/caddy/Caddyfile, the main Caddy configuration file.

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   $ sudo nano /etc/caddy/Caddyfile

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6. Add the following directive at the end of the /etc/caddy/Caddyfile file.

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   import hosts/*

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   Save and close the file.

   The above import directive instructs Caddy to include additional configuration files from the /etc/caddy/hosts directory.

7. Create a new virtual host configuration file in the /etc/caddy/hosts/ directory. For example, app.example.com.

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   $ sudo nano /etc/caddy/hosts/app.example.com

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8. Add the following configurations to the file.

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

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   Save and close the file.

   The above configuration creates a new virtual host that delivers web applications for the app.example.com domain. Within the configuration:

   • app.example.com: Creates a new virtual host profile that listens for HTTP connections for the app.example.com domain.
   • tls: Sets the email address for validating Let's Encrypt SSL certificates.
   • root: Sets the virtual host web directory.
   • file_server: Enables serving static files.
   • index: Sets the default file to serve when an HTTP client requests your domain.
   • log: Enables and specifies access and error logging.
   • output: Sets the location of the access log file.
   • format: Specifies the log file format.

9. Validate the Caddy configuration for errors.

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   $ caddy validate --config /etc/caddy/hosts/app.example.com --adapter caddyfile

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   If you receive the following warning:

   WARN    Caddyfile input is not formatted; run 'caddy fmt --overwrite' to fix inconsistencies    {"adapter": "caddyfile", "file": "/etc/caddy/hosts/app.example.com", "line": 2}

   Run the following command to correct the configuration file.

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   $ sudo caddy fmt --overwrite /etc/caddy/hosts/app.example.com

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10. Create the Caddy logs directory.

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    $ sudo mkdir /var/log/caddy

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11. Reload the Caddy webserver to apply the configuration changes.

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    $ sudo systemctl reload caddy

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Secure the Caddy Server

Caddy runs under the caddy user and group. The user enables the webserver to read and write configuration files on the server. Follow the steps below to restrict access to the Caddy configuration files and the virtual host web applications directory.

1. Grant Caddy access to the Caddy logs directory.

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   $ sudo chown -R caddy:caddy /var/log/caddy

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2. Grant Caddy access to the /etc/caddy directory.

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

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3. Grant Caddy access to the virtual host web applications directory.

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   $ sudo chown -R caddy:caddy /var/www/app.example.com/html

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Configure SELinux

SELinux is active and blocks specific application operations on Rocky Linux 9 by default. Follow the steps below to configure SELinux and grant the Caddy webserver access to the web applications directory.

1. Enable the webserver file security context on the virtual host web applications directory.

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   $ sudo semanage fcontext -a -t httpd_sys_rw_content_t "/var/www/app.example.com/html(/.*)?"

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2. Apply the SELinux policy.

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   $ sudo restorecon -Rv /var/www/app.example.com/html/

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3. Allow Caddy to create external network connections.

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   $ sudo setsebool -P httpd_can_network_connect 1

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Set Up Firewall Rules

Caddy delivers web applications using the HTTP port 80 and HTTPS port 443 depending on the virtual host configurations. Follow the steps below to enable the default Firewalld utility and enable network connections to all required ports.

1. View the firewall status to ensure the firewall is running.

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   $ sudo firewall-cmd --state

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   Your output should look like the one below when active.

   running

2. Allow HTTP port 80 through the firewall.

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   $ sudo firewall-cmd --permanent --zone=public --add-service=http

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3. Allow HTTPS port 443 through the firewall.

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   $ sudo firewall-cmd --permanent --zone=public --add-service=https

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4. Reload the firewall to apply the new changes.

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   $ sudo firewall-cmd --reload

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5. Open a web browser and access your virtual host domain (For example, app.example.com) to run your web application.

   https://app.example.com

   

Conclusion

You have installed Caddy on Rocky Linux 9 and set up a virtual host configuration to serve web applications. You can also implement Caddy as a reverse proxy or a load balancer. For more information, visit the Caddy documentation.