Book Image

Mastering Linux Administration

By : Alexandru Calcatinge, Julian Balog
Book Image

Mastering Linux Administration

By: Alexandru Calcatinge, Julian Balog

Overview of this book

Linux plays a significant role in modern data center management and provides great versatility in deploying and managing your workloads on-premises and in the cloud. This book covers the important topics you need to know about for your everyday Linux administration tasks. The book starts by helping you understand the Linux command line and how to work with files, packages, and filesystems. You'll then begin administering network services and hardening security, and learn about cloud computing, containers, and orchestration. Once you've learned how to work with the command line, you'll explore the essential Linux commands for managing users, processes, and daemons and discover how to secure your Linux environment using application security frameworks and firewall managers. As you advance through the chapters, you'll work with containers, hypervisors, virtual machines, Ansible, and Kubernetes. You'll also learn how to deploy Linux to the cloud using AWS and Azure. By the end of this Linux book, you'll be well-versed with Linux and have mastered everyday administrative tasks using workflows spanning from on-premises to the cloud. If you also find yourself adopting DevOps practices in the process, we'll consider our mission accomplished.
Table of Contents (20 chapters)
Section 1: Linux Basic Administration
Section 2: Advanced Linux Server Administration
Section 3: Cloud Administration

Managing groups

Linux uses groups to organize users. Simply put, a group is a collection of users sharing a common attribute. Examples of such groups could be employees, developers, managers, and so on. In Linux, a group is uniquely identified by a GID. Users within the same group share the same GID.

From a user's perspective, there are two types of groups, outlined here:

  • Primary group—The user's initial (default) login group
  • Supplementary groups—A list of groups the user is also a member of; also known as secondary groups

Every Linux user is a member of a primary group. A user can belong to multiple supplementary groups or no supplementary groups at all. In other words, there is one mandatory primary group associated with each Linux user, and a user can have multiple or no supplementary group memberships.

From a practical point of view, we can look at groups as a permissive context of collaboration for a select number of users. Imagine...