Book Image

CentOS 7 Linux Server Cookbook - Second Edition

By : Jonathan Hobson
Book Image

CentOS 7 Linux Server Cookbook - Second Edition

By: Jonathan Hobson

Overview of this book

This book will provide you with a comprehensive series of starting points that will give you direct access to the inner workings of the latest CentOS version 7 and help you trim the learning curve to master your server. You will begin with the installation and basic configuration of CentOS 7, followed by learning how to manage your system, services and software packages. You will then gain an understanding of how to administer the file system, secure access to your server and configure various resource sharing services such as file, printer and DHCP servers across your network. Further on, we cover advanced topics such as FTP services, building your own DNS server, running database servers, and providing mail and web services. Finally, you will get a deep understanding of SELinux and you will learn how to work with Docker operating-system virtualization and how to monitor your IT infrastructure with Nagios. By the end of this book, you will have a fair understanding of all the aspects of configuring, implementing and administering CentOS 7 Linux server and how to put it in control.
Table of Contents (22 chapters)
CentOS 7 Linux Server Cookbook Second Edition
About the Authors
About the Reviewer

Troubleshooting SELinux

In this recipe, you will learn how to troubleshoot SELinux policies, which is most often needed when access to some SELinux objects has been denied and you need to find out the reasons for it. In this recipe, we will show you how to work with the sealert tool, which will create human-readable and understandable error messages to work with.

Getting ready

To complete this recipe, you will require a working installation of the CentOS 7 operating system with root privileges. It is assumed that you are working through this chapter recipe by recipe, so by now you should have installed the SELinux tools and applied the Working with policies recipe in this chapter, as we will produce some SELinux denial events in order to show you how to use the log file tools.

How to do it...

  1. To begin, login as root and provoke a SELinux denial event:

    touch /var/www/html/test2.html
    semanage fcontext -a -t user_tmp_t /var/www/html/test2.html
    restorecon -v /var/www/html/test2.html
    curl http:/...