PHP 8.x

Install and manage PHP 8.x on Linux VPS, php-fpm, multiple versions, configuration and optimization

PHP 8.x is the modern standard for web applications. This guide covers installation, configuration, and optimization on Ubuntu/Debian and CentOS/AlmaLinux systems.

Installation

Ubuntu / Debian

Add the official Ondrej PHP PPA for latest versions:

apt update
apt install -y software-properties-common
add-apt-repository ppa:ondrej/php
apt update
apt install php8.2 php8.2-fpm php8.2-cli

For PHP 8.3:

apt install php8.3 php8.3-fpm php8.3-cli

CentOS / AlmaLinux

Use the Remi repository:

dnf install -y https://rpms.remirepo.net/enterprise/remi-release-9.rpm
dnf module enable php:remi-8.2
dnf install php php-fpm

Common Extensions

Install essential PHP modules:

apt install php8.2-curl php8.2-mbstring php8.2-xml php8.2-zip php8.2-gd php8.2-mysql php8.2-redis php8.2-opcache php8.2-intl

Verify installed extensions:

php -m
php -i | grep "extension_dir"

Configuration

php.ini Settings

Edit /etc/php/8.2/fpm/php.ini:

memory_limit = 512M
upload_max_filesize = 100M
post_max_size = 100M
max_execution_time = 300
max_input_time = 300

Opcache Optimization

In the same php.ini file:

opcache.enable = 1
opcache.memory_consumption = 256
opcache.interned_strings_buffer = 16
opcache.max_accelerated_files = 10000
opcache.revalidate_freq = 60
opcache.fast_shutdown = 1
opcache.enable_cli = 1

Verify opcache is loaded:

php -i | grep -i opcache

PHP-FPM Management

Pool Configuration

Edit /etc/php/8.2/fpm/pool.d/www.conf:

[www]
user = www-data
group = www-data
listen = /run/php/php8.2-fpm.sock
listen.owner = www-data
listen.group = www-data

pm = dynamic
pm.max_children = 20
pm.start_servers = 5
pm.min_spare_servers = 3
pm.max_spare_servers = 10
pm.max_requests = 1000

Process management modes:

static - Fixed number of processes
dynamic - Adjusts based on load
ondemand - Creates processes only when needed

Service Management

# Start and enable
systemctl start php8.2-fpm
systemctl enable php8.2-fpm

# Check status
systemctl status php8.2-fpm

# Restart after config changes
systemctl reload php8.2-fpm

Multiple PHP Versions

Run PHP 7.4 and 8.2 simultaneously with different sockets:

Install both versions:

apt install php7.4 php7.4-fpm
apt install php8.2 php8.2-fpm

Configure separate pools in /etc/php/7.4/fpm/pool.d/www.conf:

listen = /run/php/php7.4-fpm.sock

And in /etc/php/8.2/fpm/pool.d/www.conf:

listen = /run/php/php8.2-fpm.sock

Start both:

systemctl start php7.4-fpm php8.2-fpm

Nginx + PHP-FPM

Configure Nginx to use PHP-FPM:

server {
    listen 80;
    server_name example.com;
    root /var/www/example.com;

    index index.php index.html;

    location ~ \.php$ {
        fastcgi_pass unix:/run/php/php8.2-fpm.sock;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }

    location ~ /\.ht {
        deny all;
    }
}

Test and reload:

nginx -t
systemctl reload nginx

Useful Commands

# Check PHP version
php -v

# List loaded modules
php -m

# Show php.ini location
php --ini

# Get phpinfo() output
php -i

# Test specific extension
php -r "echo extension_loaded('curl') ? 'Loaded' : 'Not loaded';"

Verification

Create /var/www/example.com/info.php:

<?php
phpinfo();
?>

Access via browser at http://example.com/info.php to verify everything is running.

PHP 7.x reached end-of-life and is no longer supported. Never use PHP 7.x in production. Migrate to PHP 8.2+ for security, performance, and modern features.

Common Issues

If PHP files are downloaded instead of executed, check that the Nginx location block matches .php$ and fastcgi_pass points to the correct socket path.

For "Connection refused" errors, verify PHP-FPM is running:

systemctl status php8.2-fpm
ps aux | grep php-fpm

Check socket exists:

ls -la /run/php/php8.2-fpm.sock

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