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

Adjusting kernel scheduling parameters to better manage processes

The Linux kernel is a highly configurable piece of software, so there’s a whole world of tunables that can be used for adjusting its behavior: for processes, network cards, disk, memory, and more.

The most common tunables are the nice process value and the I/O priority, which regulate, respectively, the prioritization versus other processes of the CPU and I/O time.

For interacting with processes we’re about to start, we can use the nice or ionice commands, prepending the command we want to execute with some parameters (remember to check the man contents for each one to get the full available range of options). Just remember that for nice, processes can go from –20 to +19, with 0 being the standard one, -20 the highest priority, and 19 the lowest priority (the higher the value, the nicer the process is).

Each process has a likelihood of getting kernel attention to run. By changing the priority...