Preface

CentOS (Community Enterprise Operating System) is known as a robust, stable, and generally trouble-free operating system that is particularly well-suited to the role of a server. As a faithful adaption of RHEL, CentOS has been with us since its initial release in May 2004. It is used by a significant number of servers across the world, by an increasing number of individuals and businesses for a variety of needs, and it can be found in many mission critical situations. CentOS is considered to be a favorite among Linux professionals, and if it is configured correctly, serviced, and maintained, in most instances, a CentOS-based server should never give rise to any major complications. However, there are occasions when things do go wrong, and in such a situation, where the old joke of "rebooting the machine" is not the most appropriate form of action, then your only recourse is to consider troubleshooting the system.

Based on the overall theme of troubleshooting a CentOS 7 server, the purpose of this book is to take you on a journey across the whole spectrum of issue-based problem solving. Active processes, the networking environment, package management, users, directories and files, shared resources, security, databases, web-based services, and DNS will all be encountered with the sole purpose of building your knowledge base and enabling you to develop a fresh approach to problem solving.