Book Image

Red Hat Enterprise Linux Server Cookbook

By : Jakub Gaj, William Leemans
Book Image

Red Hat Enterprise Linux Server Cookbook

By: Jakub Gaj, William Leemans

Overview of this book

Dominating the server market, the Red Hat Enterprise Linux operating system gives you the support you need to modernize your infrastructure and boost your organization’s efficiency. Combining both stability and flexibility, RHEL helps you meet the challenges of today and adapt to the demands of tomorrow. This practical Cookbook guide will help you get to grips with RHEL 7 Server and automating its installation. Designed to provide targeted assistance through hands-on recipe guidance, it will introduce you to everything you need to know about KVM guests and deploying multiple standardized RHEL systems effortlessly. Get practical reference advice that will make complex networks setups look like child’s play, and dive into in-depth coverage of configuring a RHEL system. Also including full recipe coverage of how to set up, configuring, and troubleshoot SELinux, you’ll also discover how secure your operating system, as well as how to monitor it.
Table of Contents (17 chapters)
Red Hat Enterprise Linux Server Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Introduction


Ansible is an easy-to-use agentless system configuration management tool. It allows us to deploy complex configurations without the hassle of a complex interface or language.

Ansible uses playbooks, which are collections of tasks to deploy configurations and applications to multiple nodes over SSH in a controlled way. However, it doesn't stop there.

Ansible's modules, which are used to execute tasks, are all built to be idempotent in their execution.

The definition of Idempotence, according to Wikipedia, is as follows:

Idempotence (/ˌaɪdɨmˈpoʊtəns/ eye-dəm-poh-təns [citation needed]) is the property of certain operations in mathematics and computer science that can be applied multiple times without changing the result beyond the initial application.

In short, any module will detect the changes to be applied and perform them. If it doesn't need to change anything, it will not reapply the requested changes or interfere with file metadata.

The Ansible company also provides Tower, a paid...