Book Image

Mastering CentOS 7 Linux Server

By : Mohamed Alibi, BHASKARJYOTI ROY
Book Image

Mastering CentOS 7 Linux Server

By: Mohamed Alibi, BHASKARJYOTI ROY

Overview of this book

Most server infrastructures are equipped with at least one Linux server that provides many essential services, both for a user's demands and for the infrastructure itself. Setting up a sustainable Linux server is one of the most demanding tasks for a system administrator to perform. However, learning multiple, new technologies to meet all of their needs is time-consuming. CentOS 7 is the brand new version of the CentOS Linux system under the RPM (Red Hat) family. It is one of the most widely-used operating systems, being the choice of many organizations across the world. With the help of this book, you will explore the best practices and administration tools of CentOS 7 Linux server along with implementing some of the most common Linux services. We start by explaining the initial steps you need to carry out after installing CentOS 7 by briefly explaining the concepts related to users, groups, and right management, along with some basic system security measures. Next, you will be introduced to the most commonly used services and shown in detail how to implement and deploy them so they can be used by internal or external users. Soon enough, you will be shown how to monitor the server. We will then move on to master the virtualization and cloud computing techniques. Finally, the book wraps up by explaining configuration management and some security tweaks. All these topics and more are covered in this comprehensive guide, which briefly demonstrates the latest changes to all of the services and tools with the recent shift from CentOS 6 to CentOS 7.
Table of Contents (16 chapters)
Mastering CentOS 7 Linux Server
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

SELinux users


As explained before, SELinux users are different from normal Linux users. SELinux users are defined in the policy that's loaded into the memory at boot time, and there are only a few of these users.

After SELinux is enforced, each regular user account is mapped to a SELinux user account. There can be multiple user accounts mapped to the same SELinux user. This enables the normal user account to inherit the permission of its SELinux counterpart.

To view the mapping, we will run the following command:

semanage login -l

Here, we will find that there are only three Login Names as shown in the preceding screenshot representing the Linux user accounts. Any Linux user is mapped to the entry shown as __default__ here. The user root is not mapped to default, instead it has its own entry and there is system_u for the running processes or services. The second column indicates the SELinux user they are mapped to. Normal user accounts and roots are mapped to unconfined_u, whereas the processes...