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Complete Guide on How to Install PHP Framework Slim using LAMP Stack on AlmaLinux 8

The PHP Slim framework is a lightweight, fast, and efficient micro-framework for building RESTful-based web applications and APIs. In this guide, we will discuss in a comprehensive, structured, and in-depth way how to install the Slim Framework using LAMP Stack (Linux, Apache, MySQL, PHP) on the AlmaLinux 8 operating system, an enterprise distro that is the successor to CentOS.

Prerequisites​

  • Full root access
  • Domain (optional)
  • Basic Linux Command Line

Preparation​

danger

Make sure the firewall and SELinux have been adjusted or temporarily disabled if you want to avoid problems during the initial installation.

Before starting the Slim installation, make sure your AlmaLinux 8 server is up to date and ready to install the LAMP Stack (Linux, Apache, MariaDB, PHP).

dnf update -y
dnf install epel-release -y

Install Apache​

Apache is a reliable web server and is widely used in production environments. To install it, run the following command:

dnf install httpd -y

Once the installation is complete, enable and start the Apache service with the following command:

systemctl enable --now httpd

To allow access to the server via HTTP and HTTPS, allow the firewall:

firewall-cmd --permanent --add-service={http,https}
firewall-cmd --reload

Install PHP​

PHP (Hypertext Preprocessor) is a server-side programming language that is crucial in this stack. We will install PHP 8 from the Remi Repository to use the latest version of PHP.

Run the following command to install the Remi Repository:

dnf install -y https://rpms.remirepo.net/enterprise/remi-release-8.rpm

Then list the available PHP using the following command:

dnf module list php

Output example:

AlmaLinux 8 - AppStream
Name                            Stream                              Profiles                                              Summary                                         
php                             7.2 [d]                             common [d], devel, minimal                            PHP scripting language                          
php                             7.3                                 common [d], devel, minimal                            PHP scripting language                          
php                             7.4                                 common [d], devel, minimal                            PHP scripting language                          
php                             8.0                                 common [d], devel, minimal                            PHP scripting language                          
php                             8.2                                 common [d], devel, minimal                            PHP scripting language                          

Remi's Modular repository for Enterprise Linux 8 - x86_64
Name                            Stream                              Profiles                                              Summary                                         
php                             remi-7.2                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-7.3                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-7.4                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-8.0                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-8.1                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-8.2                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-8.3                            common [d], devel, minimal                            PHP scripting language                          
php                             remi-8.4                            common [d], devel, minimal                            PHP scripting language                          

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled

Enable the desired PHP module version. For example, for PHP 8.4, run the following command:

dnf module reset php -y
dnf module enable php:remi-8.4 -y

Once the repository is active, we can proceed with installing PHP along with the commonly used essential modules:

dnf install -y php php-cli php-common php-mysqlnd php-fpm php-opcache php-gd php-curl php-mbstring php-xml php-json php-soap php-bcmath

Check the installed PHP version with the following command:

php -v

Install MariaDB​

MariaDB is a replacement for MySQL and is compatible with MySQL-based applications. Run the following command to install it:

dnf module list mariadb

Output example:

AlmaLinux 8 - AppStream
Name                                Stream                               Profiles                                               Summary                                   
mariadb                             10.3 [d]                             client, galera, server [d]                             MariaDB Module                            
mariadb                             10.5                                 client, galera, server [d]                             MariaDB Module                            
mariadb                             10.11                                client, galera, server [d]                             MariaDB Module                            

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled

The output above shows that the default version of MariaDB is 10.11 (the latest version from the OS). However, we'll use MariaDB version 11.4.7 using the official repository at https://mariadb.org/download/ and then reset MariaDB to remove it from the OS's default repository:

dnf module reset mariadb

Run the following command to add the MariaDB version 11.4.7 repository:

nano /etc/yum.repos.d/MariaDB.repo

Add the following parameters:

# MariaDB 11.4 RedHatEnterpriseLinux repository list - created 2025-07-31 14:04 UTC
# https://mariadb.org/download/
[mariadb]
name = MariaDB
# rpm.mariadb.org is a dynamic mirror if your preferred mirror goes offline. See https://mariadb.org/mirrorbits/ for details.
# baseurl = https://rpm.mariadb.org/11.4/rhel/$releasever/$basearch
baseurl = https://mirror.its.dal.ca/mariadb/yum/11.4/rhel/$releasever/$basearch
module_hotfixes = 1
# gpgkey = https://rpm.mariadb.org/RPM-GPG-KEY-MariaDB
gpgkey = https://mirror.its.dal.ca/mariadb/yum/RPM-GPG-KEY-MariaDB
gpgcheck = 1

Then run the following command to install MariaDB:

dnf install MariaDB-server MariaDB-client

Enable and activate the MariaDB service:

systemctl enable --now mariadb
systemctl status mariadb

Before using it for production or testing, it is best to secure the MariaDB installation first by running the following command:

mariadb-secure-installation

Then follow the instructions that appear:

  • Enter current password for root (enter for none) → [ENTER]
  • Switch to unix_socket authentication → Y
  • Change the root password? → Y
  • Remove anonymous users? → Y
  • Disallow root login remotely? Y
  • Remove test database and access to it? Y
  • Reload privilege tables now? Y

Install Slim​

Before installing Slim, we'll first create a virtual host and database (to store Slim's content, configuration, and structure). Run the following command to create a virtual host:

info

Because the Slim Framework is minimalist, it doesn't have a built-in ORM or database connection like Laravel or Symfony.

info

Make sure you're using a valid domain (FQDN) and that the DNS A record is pointed to the server IP address used on your server.

nano /etc/httpd/conf.d/focusnic.biz.id.conf

Fill in the following parameters:

/etc/httpd/conf.d/focusnic.biz.id.conf
<VirtualHost *:80>
    ServerAdmin webmaster@focusnic.biz.id
    ServerName focusnic.biz.id
    ServerAlias www.focusnic.biz.id
    DocumentRoot /var/www/focusnic.biz.id/slimapp/public

    <Directory /var/www/focusnic.biz.id>
        AllowOverride All
        Require all granted
    </Directory>

    ErrorLog /var/log/httpd/focusnic.biz.id-error.log
    CustomLog /var/log/httpd/focusnic.biz.id-access.log combined
</VirtualHost>

Then create a directory on the virtualhost above:

mkdir -p /var/www/focusnic.biz.id

Restart Apache to save changes:

apachectl configtest
systemctl restart httpd

Download Composer and install it with the following command:

info

Composer will be required for Slim management, such as installing dependencies and other requirements during development or production.

curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

Check composer version:

composer --version

Output example:

Composer version 2.8.10 2025-07-10 19:08:33
PHP version 8.4.11 (/usr/bin/php)

Download the Slim file and place it in the directory according to the virtualhost, we will download Slim and create a project with the name slimapp using composer:

cd /var/www/focusnic.biz.id/
composer create-project slim/slim-skeleton slimapp

Adjust permissions on the Slim directory:

find /var/www/focusnic.biz.id/slimapp -type f -exec chmod 644 {} \;
find /var/www/focusnic.biz.id/slimapp -type d -exec chmod 755 {} \;
chown -R apache:apache /var/www/focusnic.biz.id

Access the Slim installation via a browser, for example: http://focusnic.biz.id. If the installation is successful, the following default Slim page will appear.

Troubleshooting​

  1. 404 Not Found
    Ensure Apache's mod_rewrite is enabled and .htaccess is used.

  2. Slim Not Responding
    Ensure the index.php file is written correctly and the dependency via Composer has been successfully installed.

  3. Permission Denied
    Ensure the Apache user's directory is apache:apache or has been chown to your user.

  4. Autoload Error
    Rerun composer install if the vendor file is missing.

Conclusion​

The Slim PHP Framework provides a fast, lightweight, and powerful solution for building web-based applications and APIs. By following this comprehensive guide, we successfully installed the Slim Framework using the LAMP Stack on AlmaLinux 8 with an optimal and secure configuration.

The step-by-step instructions, from installing LAMP and Composer to configuring the Apache virtual host, are explained in detail and systematically so that even beginners can follow along easily.

Q: Is the Slim Framework suitable for large applications?
A: Slim is designed as a micro-framework, but with its modular architecture, it is possible to use it for large applications with the addition of external components.

Q: Can it be used with Nginx?
A: Yes, Slim can run on top of Nginx, but this guide focuses on using Apache as part of a LAMP Stack.

Q: Is Composer mandatory?
A: It is mandatory. Composer is the primary dependency manager in the modern PHP ecosystem, including Slim.

Q: How do I deploy to production?
A: Use a valid domain, enable HTTPS, optimize the Apache configuration, and run the application in production mode.

Q: Is AlmaLinux suitable for production?
A: Absolutely. AlmaLinux is a stable successor to CentOS and is supported by the enterprise community.

Further References: