July 3, 2026 / Linux, Servers, Ubuntu

Install PHP-FPM and Common PHP Extensions on Ubuntu

Tags: linux, php, php-fpm, server setup, ubuntu, wordpress

PHP-FPM is the usual way to run PHP behind Nginx on Ubuntu. It gives you a long-running PHP process manager instead of starting PHP from scratch for every request.

This guide walks through installing PHP-FPM, adding common PHP extensions, detecting the installed PHP version, tuning php.ini, and restarting the right PHP-FPM service.

What the Script Does

The deployment script this article is based on:

Installs PHP, PHP-FPM, PHP CLI, and common extensions.
Detects the installed PHP major/minor version.
Finds the matching PHP-FPM service name.
Backs up the PHP-FPM and CLI php.ini files.
Updates upload, post, memory, and execution-time limits.
Enables and restarts PHP-FPM.

Install PHP and Extensions

Run:

sudo apt update

sudo apt install -y \
    php \
    php-fpm \
    php-cli \
    php-common \
    php-mysql \
    php-curl \
    php-gd \
    php-imagick \
    php-mbstring \
    php-xml \
    php-zip \
    php-intl \
    php-bcmath \
    php-redis \
    php-soap \
    php-readline \
    php-bz2 \
    php-gmp \
    php-ldap \
    php-sqlite3 \
    php-tidy \
    php-dev

Those extensions cover many common WordPress and PHP application needs, including MySQL, image handling, XML, ZIP files, Redis, SOAP, and multibyte strings.

Detect the PHP Version

Ubuntu package names include the PHP version in the FPM service name.

Detect it with:

PHP_VERSION="$(php -r 'echo PHP_MAJOR_VERSION.".".PHP_MINOR_VERSION;')"
PHP_FPM_SERVICE="php${PHP_VERSION}-fpm"
PHP_FPM_INI="/etc/php/${PHP_VERSION}/fpm/php.ini"
PHP_CLI_INI="/etc/php/${PHP_VERSION}/cli/php.ini"

echo "PHP version: ${PHP_VERSION}"
echo "PHP-FPM service: ${PHP_FPM_SERVICE}"
echo "PHP-FPM ini: ${PHP_FPM_INI}"
echo "PHP CLI ini: ${PHP_CLI_INI}"

Example output:

PHP version: 8.3
PHP-FPM service: php8.3-fpm
PHP-FPM ini: /etc/php/8.3/fpm/php.ini
PHP CLI ini: /etc/php/8.3/cli/php.ini

Back Up PHP Config Files

Create a backup folder:

sudo mkdir -p /opt/server-backups/php
timestamp="$(date +%Y%m%d%H%M%S)"

Back up both PHP-FPM and PHP CLI settings:

sudo cp "${PHP_FPM_INI}" "/opt/server-backups/php/php.ini.fpm.before.${timestamp}.bak"
sudo cp "${PHP_CLI_INI}" "/opt/server-backups/php/php.ini.cli.before.${timestamp}.bak"

Tune PHP-FPM

This example sets:

upload_max_filesize = 64M
post_max_size = 64M
memory_limit = 256M
max_execution_time = 300

Apply them to the PHP-FPM php.ini:

sudo sed -i "s/^upload_max_filesize = .*/upload_max_filesize = 64M/" "${PHP_FPM_INI}"
sudo sed -i "s/^post_max_size = .*/post_max_size = 64M/" "${PHP_FPM_INI}"
sudo sed -i "s/^memory_limit = .*/memory_limit = 256M/" "${PHP_FPM_INI}"
sudo sed -i "s/^max_execution_time = .*/max_execution_time = 300/" "${PHP_FPM_INI}"

For CLI PHP, a common setup is to keep memory aligned but allow long-running command-line jobs:

sudo sed -i "s/^memory_limit = .*/memory_limit = 256M/" "${PHP_CLI_INI}"
sudo sed -i "s/^max_execution_time = .*/max_execution_time = 0/" "${PHP_CLI_INI}"

Restart PHP-FPM

Enable and restart the detected service:

sudo systemctl enable "${PHP_FPM_SERVICE}"
sudo systemctl restart "${PHP_FPM_SERVICE}"
sudo systemctl is-active --quiet "${PHP_FPM_SERVICE}"

Save after-change backups:

sudo cp "${PHP_FPM_INI}" "/opt/server-backups/php/php.ini.fpm.after.${timestamp}.bak"
sudo cp "${PHP_CLI_INI}" "/opt/server-backups/php/php.ini.cli.after.${timestamp}.bak"

Full Script

Here is the full Bash script used for this PHP-FPM and extension install workflow:

#!/usr/bin/env bash

__show_script_usage() {
  cat <<'__SCRIPT_USAGE__'
# Install-PHP.sh

Installs PHP-FPM and required PHP extensions, then applies common PHP limits.

## Example Usage

```bash
cd /opt/DevOps/Scripts
sudo bash ./Install-PHP.sh
```

## Notes

This modifies PHP CLI/FPM `php.ini` files, writes backups under `/opt/DevOps/Backups/PHP`, and restarts PHP-FPM.
__SCRIPT_USAGE__
}

if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
  case "${1:-}" in
    -h|--help|--usage)
      __show_script_usage
      exit 0
      ;;
  esac
fi

# ============================================================
# Variables
# ============================================================

DEVOPS_BACKUP_DIR="/opt/DevOps/Backups/PHP"

PHP_UPLOAD_MAX_FILESIZE="64M"
PHP_POST_MAX_SIZE="64M"
PHP_MEMORY_LIMIT="256M"
PHP_MAX_EXECUTION_TIME="300"

# ============================================================
# Safety
# ============================================================

set -euo pipefail

echo "Installing PHP and useful extensions..."

if [ "$EUID" -ne 0 ]; then
    echo "ERROR: Run with sudo."
    exit 1
fi

# ============================================================
# Install PHP
# ============================================================

echo "Updating package lists..."
apt update

echo "Installing PHP-FPM, PHP CLI, and useful PHP extensions..."

apt install -y \
    php \
    php-fpm \
    php-cli \
    php-common \
    php-mysql \
    php-curl \
    php-gd \
    php-imagick \
    php-mbstring \
    php-xml \
    php-zip \
    php-intl \
    php-bcmath \
    php-redis \
    php-soap \
    php-readline \
    php-bz2 \
    php-gmp \
    php-ldap \
    php-sqlite3 \
    php-tidy \
    php-dev

# ============================================================
# Detect PHP Version
# ============================================================

PHP_VERSION="$(php -r 'echo PHP_MAJOR_VERSION.".".PHP_MINOR_VERSION;')"
PHP_FPM_SERVICE="php${PHP_VERSION}-fpm"
PHP_FPM_INI="/etc/php/${PHP_VERSION}/fpm/php.ini"
PHP_CLI_INI="/etc/php/${PHP_VERSION}/cli/php.ini"

echo "Detected PHP version: ${PHP_VERSION}"
echo "Detected PHP-FPM service: ${PHP_FPM_SERVICE}"

# ============================================================
# Backup Config
# ============================================================

echo "Creating PHP backup directory..."
mkdir -p "${DEVOPS_BACKUP_DIR}"

TIMESTAMP="$(date +%Y%m%d%H%M%S)"

if [ -f "${PHP_FPM_INI}" ]; then
    cp "${PHP_FPM_INI}" "${DEVOPS_BACKUP_DIR}/php.ini.fpm.before.${TIMESTAMP}.bak"
fi

if [ -f "${PHP_CLI_INI}" ]; then
    cp "${PHP_CLI_INI}" "${DEVOPS_BACKUP_DIR}/php.ini.cli.before.${TIMESTAMP}.bak"
fi

# ============================================================
# Configure PHP-FPM
# ============================================================

echo "Configuring PHP-FPM php.ini..."

sed -i "s/^upload_max_filesize = .*/upload_max_filesize = ${PHP_UPLOAD_MAX_FILESIZE}/" "${PHP_FPM_INI}"
sed -i "s/^post_max_size = .*/post_max_size = ${PHP_POST_MAX_SIZE}/" "${PHP_FPM_INI}"
sed -i "s/^memory_limit = .*/memory_limit = ${PHP_MEMORY_LIMIT}/" "${PHP_FPM_INI}"
sed -i "s/^max_execution_time = .*/max_execution_time = ${PHP_MAX_EXECUTION_TIME}/" "${PHP_FPM_INI}"

# ============================================================
# Configure PHP CLI
# ============================================================

echo "Configuring PHP CLI php.ini..."

sed -i "s/^memory_limit = .*/memory_limit = ${PHP_MEMORY_LIMIT}/" "${PHP_CLI_INI}"
sed -i "s/^max_execution_time = .*/max_execution_time = 0/" "${PHP_CLI_INI}"

# ============================================================
# Backup After Config
# ============================================================

cp "${PHP_FPM_INI}" "${DEVOPS_BACKUP_DIR}/php.ini.fpm.after.${TIMESTAMP}.bak"
cp "${PHP_CLI_INI}" "${DEVOPS_BACKUP_DIR}/php.ini.cli.after.${TIMESTAMP}.bak"

# ============================================================
# Restart PHP-FPM
# ============================================================

echo "Enabling PHP-FPM..."
systemctl enable "${PHP_FPM_SERVICE}"

echo "Restarting PHP-FPM..."
systemctl restart "${PHP_FPM_SERVICE}"

echo "Checking PHP-FPM status..."
systemctl is-active --quiet "${PHP_FPM_SERVICE}"

# ============================================================
# Complete
# ============================================================

echo "PHP install complete."
echo "PHP version: ${PHP_VERSION}"
echo "PHP-FPM service: ${PHP_FPM_SERVICE}"
echo "PHP-FPM ini: ${PHP_FPM_INI}"
echo "PHP CLI ini: ${PHP_CLI_INI}"

Troubleshooting

If PHP-FPM does not restart, check:

sudo systemctl status "${PHP_FPM_SERVICE}"
sudo journalctl -u "${PHP_FPM_SERVICE}" -xe

If Nginx returns 502 Bad Gateway, confirm that the Nginx site config points to the correct PHP-FPM socket for your PHP version.

Quick Reference

PHP_VERSION="$(php -r 'echo PHP_MAJOR_VERSION.".".PHP_MINOR_VERSION;')"
PHP_FPM_SERVICE="php${PHP_VERSION}-fpm"
sudo systemctl restart "${PHP_FPM_SERVICE}"
sudo systemctl status "${PHP_FPM_SERVICE}"

The important habit is to detect the installed PHP version instead of hard-coding one. That makes the script work across different Ubuntu releases.

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