Book Image

Red Hat Enterprise Linux 9 Administration - Second Edition

By : Pablo Iranzo Gómez, Pedro Ibáñez Requena, Miguel Pérez Colino, Scott McCarty
2 (2)
Book Image

Red Hat Enterprise Linux 9 Administration - Second Edition

2 (2)
By: Pablo Iranzo Gómez, Pedro Ibáñez Requena, Miguel Pérez Colino, Scott McCarty

Overview of this book

With Red Hat Enterprise Linux 9 becoming the standard for enterprise Linux used from data centers to the cloud, Linux administration skills are in high demand. With this book, you’ll learn how to deploy, access, tweak, and improve enterprise services on any system on any cloud running Red Hat Enterprise Linux 9. Throughout the book, you’ll get to grips with essential tasks such as configuring and maintaining systems, including software installation, updates, and core services. You’ll also understand how to configure the local storage using partitions and logical volumes, as well as assign and deduplicate storage. You’ll learn how to deploy systems while also making them secure and reliable. This book provides a base for users who plan to become full-time Linux system administrators by presenting key command-line concepts and enterprise-level tools, along with essential tools for handling files, directories, command-line environments, and documentation for creating simple shell scripts or running commands. With the help of command line examples and practical tips, you’ll learn by doing and save yourself a lot of time. By the end of the book, you’ll have gained the confidence to manage the filesystem, users, storage, network connectivity, security, and software in RHEL 9 systems on any footprint.
Table of Contents (26 chapters)
1
Part 1 – Systems Administration – Software, User, Network, and Services Management
9
Part 2 – Security with SSH, SELinux, a Firewall, and System Permissions
14
Part 3 – Resource Administration – Storage, Boot Process, Tuning, and Containers
21
Part 4 – Practical Exercises

Understanding LVM

LVM uses three layers to manage the storage devices in our systems. These layers are as follows:

  • Physical Volumes (PVs): The first layer of LVM. Assigned to the block devices directly. A physical volume can be either a partition on a disk or a full raw disk itself.
  • Volume Groups (VGs): The second layer of LVM. It groups the physical volumes to aggregate space. This is an intermediate layer and not very visible, but its role is very important.
  • Logical Volumes (LVs): The third layer of LVM. It distributes the space that the volume groups aggregate.

Let’s see the example that we want to implement using the two newly added disks:

Figure 13.4 – An example of LVM using two disks

Let’s explain this example diagram to understand all the layers:

  • We have two disks, which are Disk1 and Disk2 in the diagram.
  • Disk1 is partitioned into two partitions, Part1 and Part2.
  • Disk2 is not partitioned.
  • ...