Tech Tutorial: Deploy, Configure, and Maintain Systems for RHCE Certification #

Introduction #

The Red Hat Certified Engineer (RHCE) exam is a prestigious certification that proves an individual’s expertise in handling Red Hat Enterprise Linux (RHEL) systems. One of the key objectives of the RHCE exam is to demonstrate the ability to deploy, configure, and maintain systems effectively. This tutorial will guide you through the essential commands and procedures specific to RHEL, focusing on real-world applications and scenarios.

Step-by-Step Guide #

1. Deploying Systems #

Deployment in RHEL often starts with the installation of the operating system and its configuration for the first use. We’ll use a Kickstart file to automate the installation process.

Creating a Kickstart File #

A Kickstart file allows you to automate the RHEL installation. It can specify settings for the bootloader, partitioning, network configurations, software package installations, and scripts to be run after installation.

# Sample Kickstart configuration for a basic RHEL installation
lang en_US.UTF-8
keyboard us
timezone UTC
rootpw --plaintext RedHat123
bootloader --location=mbr
text
skipx
zerombr
clearpart --all --initlabel
autopart
auth --useshadow --passalgo=sha512
selinux --enforcing
firewall --enabled
network --bootproto=dhcp --device=eth0
url --url="http://mirror.centos.org/centos/8/BaseOS/x86_64/os/"
%packages
@core
%end

You would store this file on a network accessible server and point the installer to this file during the boot process by appending inst.ks=http://<server>/<path> to the boot options.

2. Configuring Systems #

Post-installation, systems need to be configured to match the operational requirements. This involves setting up network configurations, managing services, and configuring security settings.

Network Configuration #

RHEL uses NetworkManager for network configuration. Here is how to configure a static IP address on an Ethernet interface using the nmcli tool:

nmcli con mod eth0 ipv4.addresses 192.168.1.100/24
nmcli con mod eth0 ipv4.gateway 192.168.1.1
nmcli con mod eth0 ipv4.dns 8.8.8.8
nmcli con mod eth0 ipv4.method manual
nmcli con up eth0

Managing Services with systemctl #

Systemd is the initialization system on RHEL. It’s used to manage system services. For example, to start and enable the Apache web server:

sudo systemctl start httpd
sudo systemctl enable httpd

3. Maintaining Systems #

Maintaining systems includes updating packages, monitoring system performance, and ensuring security compliance.

Updating Packages #

Use yum or dnf (RHEL 8) to update your system packages:

sudo dnf update

Monitoring System Performance #

The top command provides a dynamic real-time view of a running system. It can display system summary information and a list of tasks currently managed by the Linux kernel.

top

Configuring Firewall #

Firewalld is the default firewall management tool on RHEL. Here’s how to allow HTTP traffic:

sudo firewall-cmd --permanent --add-service=http
sudo firewall-cmd --reload

Detailed Code Examples #

Let’s consider a scenario where you need to set up a LAMP stack on your RHEL server:

1. Install Apache, MariaDB, and PHP:

   sudo dnf install httpd mariadb-server php php-mysqlnd
   

2. Configure and start services:

   sudo systemctl start httpd
   sudo systemctl enable httpd
   sudo systemctl start mariadb
   sudo systemctl enable mariadb
   mysql_secure_installation
   

3. Test PHP processing on the web server:

   Create a file named info.php in /var/www/html with the following content:

   <?php phpinfo(); ?>
   

   Access this file via a web browser to see all PHP configuration settings.

Conclusion #

Deploying, configuring, and maintaining RHEL systems requires a deep understanding of available tools and best practices. This tutorial has covered the basics of these tasks, providing a solid foundation for your preparations for the RHCE exam. Practice these commands and procedures to build confidence and ensure you are well-prepared for the exam scenarios. Good luck!