How to Install PHP 7.4 on Ubuntu and CentOS/RHEL

PHP (PHP: Hypertext Preprocessor) is a widely-used, open-source server-side scripting language designed specifically for web development. PHP powers millions of websites and web applications worldwide, including popular content management systems like WordPress, Drupal, and Joomla.

This comprehensive guide provides step-by-step instructions for installing PHP 7.4 on both Ubuntu and CentOS/RHEL systems. Whether you're setting up a development environment or deploying a production server, this tutorial covers everything you need to know.

What is PHP?

PHP (PHP: Hypertext Preprocessor) is a popular server-side programming language primarily used for creating dynamic and interactive websites. Originally created by Rasmus Lerdorf in 1994, PHP has evolved into one of the most widely-adopted web programming languages.

Key Features of PHP

• Server-side scripting: Executes on the web server before sending content to the browser
• Cross-platform compatibility: Runs on various operating systems including Linux, Windows, and macOS
• Database integration: Excellent support for MySQL, PostgreSQL, MongoDB, and other databases
• Large community: Extensive documentation, frameworks, and third-party libraries
• Easy to learn: Simple syntax makes it accessible for beginners

PHP 7.4 Features and Benefits

PHP 7.4, released in November 2019, introduced several performance improvements and new features:

• Improved performance: Up to 50% faster than PHP 5.6
• Typed properties: Better type safety for class properties
• Arrow functions: Simplified anonymous function syntax
• Null coalescing assignment operator: Streamlined null value handling
• Foreign Function Interface (FFI): Call C functions directly from PHP

Prerequisites

Before installing PHP 7.4, ensure your system meets the following requirements:

System Requirements

• Ubuntu: 18.04 LTS, 20.04 LTS, or 22.04 LTS
• CentOS/RHEL: Version 7 or 8
• Root or sudo access: Administrative privileges required
• Internet connection: For downloading packages

Recommended Specifications

• RAM: Minimum 1GB (2GB recommended)
• Storage: At least 2GB free space
• CPU: Any modern x86_64 processor

Installing PHP 7.4 on Ubuntu

Method 1: Installing from Default Repository

Ubuntu 20.04 includes PHP 7.4 in its default repositories, making installation straightforward:

Step 1: Update System Packages

sudo apt update && sudo apt upgrade -y

This command updates the package list and upgrades existing packages to their latest versions.

Step 2: Install PHP 7.4

sudo apt install php7.4 -y

Step 3: Install Common PHP Extensions

sudo apt install php7.4-{cli,fpm,mysql,zip,gd,mbstring,curl,xml,bcmath,json} -y

This installs essential PHP extensions commonly required for web applications.

Method 2: Using Ondřej Surý PPA (For Older Ubuntu Versions)

If you're using Ubuntu 18.04 or need specific PHP versions, use the Ondřej Surý PPA:

Step 1: Install Prerequisites

sudo apt install software-properties-common -y

Step 2: Add PHP PPA Repository

sudo add-apt-repository ppa:ondrej/php -y

Step 3: Update Package Lists

sudo apt update

Step 4: Install PHP 7.4

sudo apt install php7.4 php7.4-{cli,fpm,mysql,zip,gd,mbstring,curl,xml,bcmath,json} -y

Configuring PHP with Web Servers on Ubuntu

For Apache Web Server

# Install Apache and PHP module
sudo apt install apache2 libapache2-mod-php7.4 -y

# Enable PHP module
sudo a2enmod php7.4

# Restart Apache
sudo systemctl restart apache2

For Nginx Web Server

# Install Nginx and PHP-FPM
sudo apt install nginx php7.4-fpm -y

# Start and enable services
sudo systemctl start nginx php7.4-fpm
sudo systemctl enable nginx php7.4-fpm

Installing PHP 7.4 on CentOS/RHEL

Step 1: Enable Required Repositories

For CentOS/RHEL 8

# Install EPEL repository
sudo dnf install epel-release -y

# Install Remi repository
sudo dnf install https://rpms.remirepo.net/enterprise/remi-release-8.rpm -y

For CentOS/RHEL 7

# Install EPEL repository
sudo yum install epel-release -y

# Install Remi repository
sudo yum install https://rpms.remirepo.net/enterprise/remi-release-7.rpm -y

Step 2: Configure PHP Repository

For CentOS/RHEL 8

# Reset PHP module
sudo dnf module reset php -y

# Enable PHP 7.4 module
sudo dnf module enable php:remi-7.4 -y

For CentOS/RHEL 7

# Install yum-utils
sudo yum install yum-utils -y

# Enable PHP 7.4 repository
sudo yum-config-manager --enable remi-php74

Step 3: Install PHP 7.4

For CentOS/RHEL 8

sudo dnf install php php-{cli,fpm,mysql,zip,gd,mbstring,curl,xml,bcmath,json} -y

For CentOS/RHEL 7

sudo yum install php php-{cli,fpm,mysql,zip,gd,mbstring,curl,xml,bcmath,json} -y

Configuring PHP with Web Servers on CentOS/RHEL

For Apache Web Server

# Install Apache
sudo yum install httpd -y  # CentOS/RHEL 7
# OR
sudo dnf install httpd -y  # CentOS/RHEL 8

# Start and enable services
sudo systemctl start httpd
sudo systemctl enable httpd

For Nginx Web Server

# Install Nginx
sudo yum install nginx -y  # CentOS/RHEL 7
# OR
sudo dnf install nginx -y  # CentOS/RHEL 8

# Start and enable services
sudo systemctl start nginx php-fpm
sudo systemctl enable nginx php-fpm

PHP Configuration

Basic PHP Configuration

Edit the main PHP configuration file:

sudo nano /etc/php/7.4/apache2/php.ini  # Ubuntu with Apache
sudo nano /etc/php/7.4/fpm/php.ini      # Ubuntu with Nginx
sudo nano /etc/php.ini                   # CentOS/RHEL

Recommended Configuration Settings

# Memory limit (adjust based on your needs)
memory_limit = 256M

# Maximum execution time
max_execution_time = 300

# File upload settings
upload_max_filesize = 50M
post_max_size = 50M

# Maximum number of files that can be uploaded
max_file_uploads = 20

# Timezone setting (adjust to your timezone)
date.timezone = "America/New_York"

# Error reporting (disable in production)
display_errors = Off
log_errors = On
error_log = /var/log/php_errors.log

Verification and Testing

Verify PHP Installation

Check the installed PHP version:

php -v

Expected output:

PHP 7.4.3 (cli) (built: Oct  6 2020 15:47:56) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
    with Zend OPcache v7.4.3, Copyright (c), by Zend Technologies

Check Installed Extensions

php -m

Create a PHP Test File

Create a simple PHP test file to verify web server integration:

# For Apache
sudo nano /var/www/html/info.php

# For Nginx
sudo nano /var/www/html/info.php

Add the following content:

<?php
phpinfo();
?>

Access the file through your web browser:

http://your-server-ip/info.php

Security Note: Remove this file after testing as it exposes system information.

Essential PHP Extensions

Database Extensions

# Ubuntu
sudo apt install php7.4-{mysql,pgsql,sqlite3} -y

# CentOS/RHEL
sudo yum install php-{mysqlnd,pgsql,sqlite} -y

Caching Extensions

# Ubuntu
sudo apt install php7.4-{opcache,apcu,redis,memcached} -y

# CentOS/RHEL
sudo yum install php-{opcache,apcu,redis,memcached} -y

Development Extensions

# Ubuntu
sudo apt install php7.4-{xdebug,dev} -y

# CentOS/RHEL
sudo yum install php-{xdebug,devel} -y

Troubleshooting Common Issues

Issue 1: PHP Not Working with Apache

Solution: Ensure the PHP module is enabled

# Ubuntu
sudo a2enmod php7.4
sudo systemctl restart apache2

# CentOS/RHEL
sudo systemctl restart httpd

Issue 2: Permission Denied Errors

Solution: Check file permissions and ownership

# Set correct ownership
sudo chown -R www-data:www-data /var/www/html  # Ubuntu
sudo chown -R apache:apache /var/www/html      # CentOS/RHEL

# Set correct permissions
sudo chmod -R 755 /var/www/html

Issue 3: PHP-FPM Not Starting

Solution: Check PHP-FPM configuration and logs

# Check PHP-FPM status
sudo systemctl status php7.4-fpm  # Ubuntu
sudo systemctl status php-fpm     # CentOS/RHEL

# Check error logs
sudo journalctl -u php7.4-fpm  # Ubuntu
sudo journalctl -u php-fpm     # CentOS/RHEL

Issue 4: Memory Limit Errors

Solution: Increase PHP memory limit

# Edit PHP configuration
sudo nano /etc/php/7.4/apache2/php.ini  # Ubuntu
sudo nano /etc/php.ini                   # CentOS/RHEL

# Modify memory_limit
memory_limit = 512M

# Restart web server
sudo systemctl restart apache2  # or nginx

Performance Optimization

Enable OPcache

OPcache improves PHP performance by storing precompiled script bytecode in memory:

# Add to php.ini
opcache.enable=1
opcache.memory_consumption=128
opcache.max_accelerated_files=4000
opcache.revalidate_freq=60

PHP-FPM Optimization

For Nginx setups, optimize PHP-FPM settings:

sudo nano /etc/php/7.4/fpm/pool.d/www.conf  # Ubuntu
sudo nano /etc/php-fpm.d/www.conf           # CentOS/RHEL

pm = dynamic
pm.max_children = 50
pm.start_servers = 5
pm.min_spare_servers = 5
pm.max_spare_servers = 35
pm.max_requests = 500

Security Best Practices

Disable Dangerous Functions

disable_functions = exec,passthru,shell_exec,system,proc_open,popen,parse_ini_file,show_source

Hide PHP Version

expose_php = Off

Enable Error Logging

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

Maintenance and Updates

Updating PHP on Ubuntu

sudo apt update && sudo apt upgrade php7.4*

Updating PHP on CentOS/RHEL

# CentOS/RHEL 7
sudo yum update php*

# CentOS/RHEL 8
sudo dnf update php*

Managing Multiple PHP Versions

You can install multiple PHP versions and switch between them:

# Ubuntu - Install multiple versions
sudo apt install php7.4 php8.0 php8.1

# Switch default CLI version
sudo update-alternatives --config php

# Switch Apache module version
sudo a2dismod php7.4 && sudo a2enmod php8.0
sudo systemctl restart apache2

Conclusion

PHP 7.4 remains one of the most popular programming languages for web development due to its ease of use, extensive ecosystem, and robust performance. This guide has provided comprehensive instructions for installing PHP 7.4 on both Ubuntu and CentOS/RHEL systems.

Key Takeaways

• Ubuntu users can install PHP 7.4 directly from default repositories (20.04+) or via PPA for older versions
• CentOS/RHEL users need to enable EPEL and Remi repositories before installation
• Proper configuration is essential for security and performance
• Regular updates help maintain security and stability

Next Steps

After successfully installing PHP 7.4, consider:

1. Installing a PHP framework like Laravel, Symfony, or CodeIgniter
2. Setting up a development environment with tools like Composer and Xdebug
3. Implementing security measures like firewalls and SSL certificates
4. Monitoring performance with tools like New Relic or Datadog

Whether you're building a simple website or a complex web application, PHP 7.4 provides the foundation for creating dynamic, interactive web experiences. With the knowledge gained from this guide, you're ready to start developing with PHP on your preferred Linux distribution.