How to Install PHP 8.1 in Rocky Linux 9

Updated July 13, 2024

Preparing the System

Adding Required Repositories

To install PHP 8.1 on Rocky Linux 9, you need to add the EPEL (Extra Packages for Enterprise Linux) and REMI repositories. These repositories provide extra packages and updates not found in the default Rocky Linux repositories.

EPEL Repository

Install the EPEL repository:

sudo dnf install epel-release

Benefits of EPEL:

  • Access to more software packages
  • Regular updates and security patches
  • Community-maintained repository with good packages

Tip: Verify EPEL Repository

After installing the EPEL repository, you can verify its presence by running:

dnf repolist | grep epel

This command will display the EPEL repository if it's correctly installed.

REMI Repository

Install the REMI repository:

sudo dnf install

Installing DNF Utilities

DNF utilities offer extra functions for managing packages and repositories. To install the dnf-utils package, run:

sudo dnf install dnf-utils

Configuring PHP 8.1

Enabling PHP 8.1 Remi Repository

To enable the PHP 8.1 Remi repository on Rocky Linux 9:

  1. Reset the PHP module:

    sudo dnf module reset php
  2. Install PHP 8.1 module:

    sudo dnf module install php:remi-8.1

Installing PHP 8.1 and Extensions

Install PHP 8.1 and common extensions:

sudo dnf install php php-cli php-fpm php-mysqlnd php-zip php-devel php-gd php-mcrypt php-mbstring php-curl php-xml php-pear php-bcmath php-json

Popular PHP 8.1 extensions and their uses

Extension Use Case
php-mysqlnd MySQL database connection
php-zip ZIP file handling
php-gd Image processing
php-mbstring Multibyte string handling
php-curl Making HTTP requests

Configuring PHP-FPM

  1. Start PHP-FPM service:

    sudo systemctl start php-fpm
  2. Enable PHP-FPM to start on boot:

    sudo systemctl enable php-fpm

PHP-FPM configuration tips

  • Adjust pm.max_children based on server resources
  • Set proper memory_limit in php.ini
  • Configure upload_max_filesize for file uploads

Optimizing PHP 8.1 for Production

Performance tuning

  • Enable OPcache
  • Adjust memory_limit and max_execution_time
  • Configure PHP-FPM process manager

Security considerations

  • Disable expose_php in php.ini
  • Set correct file permissions
  • Keep PHP and extensions updated

Installing PHP 8.1

Core Installation

To install PHP 8.1 on your Rocky Linux 9 web server, run this command:

sudo dnf install php

This command installs the main PHP 8.1 package and its dependencies.

Tip: Check PHP Repository

Before installing PHP, make sure you have the correct repository enabled. You can check available PHP versions with:

sudo dnf module list php

If PHP 8.1 is not listed, you may need to enable the Remi repository:

sudo dnf install epel-release
sudo dnf install
sudo dnf module enable php:remi-8.1

Verifying the Installation

After installation, check the PHP version:

php -v

You should see output like:

PHP 8.1.x (cli) (built: ...) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.x, Copyright (c) Zend Technologies

PHP Configuration

The main PHP config file is at /etc/php.ini. Here are some settings you might want to change:

Memory Limit

memory_limit = 256M

Maximum Upload File Size

upload_max_filesize = 20M
post_max_size = 20M

Error Reporting

error_reporting = E_ALL
display_errors = Off
log_errors = On
error_log = /var/log/php_errors.log

PHP-FPM Configuration

If you're using PHP-FPM (FastCGI Process Manager), you can install it with:

sudo dnf install php-fpm

Start and enable PHP-FPM:

sudo systemctl start php-fpm
sudo systemctl enable php-fpm

Testing PHP Installation

Creating a PHP Info File

To test your PHP installation, create a PHP info file:

  1. Go to the web root directory:

    cd /var/www/html
  2. Create and edit the info.php file:

    sudo nano info.php
  3. Add the phpinfo() function to the file:

  4. Save the file and exit the editor (in nano, press Ctrl+X, then Y, then Enter).

Tip: Backup Before Editing

Before creating or editing any system files, it's a good practice to create a backup. You can use the following command to make a copy of an existing file:

sudo cp /var/www/html/info.php /var/www/html/info.php.bak

This creates a backup file named info.php.bak, allowing you to revert changes if needed.

Accessing the PHP Info Page

To view your PHP configuration through a web browser:

  1. Open a web browser on your local machine.

  2. Enter this URL, replacing your_server_ip with your server's IP address or domain name:

  3. You should see a page showing details about your PHP installation.

Key Information Displayed

The PHP info page provides data about your setup:

  • PHP version
  • Loaded modules
  • Server environment
  • PHP settings


  • Version Check: A developer needs to check if the server supports PHP 8.1 features like enums.
  • Module Verification: A project needs the GD library for image processing.
  • Environment Details: Troubleshooting session issues by checking the session save path.
  • Configuration Review: Adjusting max_execution_time for a long-running script.

Security Precautions

After testing, remove the info.php file:

sudo rm /var/www/html/info.php

This step prevents unauthorized access to your server configuration details.

Finalizing the Installation

Restarting the Web Server

After installing PHP 8.1 and its modules, restart the Apache web server. This step applies the changes and makes PHP work correctly with Apache.

Restart Commands

Use one of these commands to restart the Apache web server:

Command Description
sudo systemctl restart httpd Modern command using systemd
sudo service httpd restart Traditional command for older systems

Both commands restart Apache, but systemctl is more modern and offers more options.

Tip: Using systemctl for Service Management

When using systemctl, you can perform various operations on services:

  • Start a service: sudo systemctl start httpd
  • Stop a service: sudo systemctl stop httpd
  • Restart a service: sudo systemctl restart httpd
  • Check service status: sudo systemctl status httpd These commands provide a consistent interface for managing system services.

Checking Apache Status

After restarting, check if Apache is running:

sudo systemctl status httpd

This command shows the status of the Apache service. Look for "active (running)" in the output.


If you see errors, check the Apache error log:

sudo tail -f /var/log/httpd/error_log

This command displays the last few lines of the error log and updates in real-time.

Common Issues and Solutions

  • Permission Errors: Check file permissions for your web files.
  • Module Conflicts: Check if new modules conflict with existing ones.
  • Port Conflicts: Check if another service is using port 80 or 443.

Enabling Apache on Boot

To make Apache start when your server boots up, run:

sudo systemctl enable httpd

Testing PHP Installation

After restarting Apache, test your PHP 8.1 installation:

  1. Create a test file:

    echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/phpinfo.php
  2. Access the file in your web browser: http://your_server_ip/phpinfo.php

  3. Review the PHP configuration information displayed.

Next Steps

  • Set up virtual hosts for your websites.
  • Install PHP extensions for your projects.
  • Configure PHP settings in php.ini for good performance.
  • Set up a database server if needed (e.g., MySQL, PostgreSQL).

Your PHP 8.1 installation on Rocky Linux 9 is now ready. You can start developing PHP applications or install content management systems that use PHP.