System Essentials

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Interactive labs, not module completion

The foundation of Linux knowledge. Understanding these concepts makes everything else click.

Overview

This section covers the core building blocks of Linux that every DevOps/SRE professional needs to understand. These aren’t just theoretical concepts—they’re the reality you interact with every time you run a command or debug an issue.

Modules

#	Module	Description	Time
1.1	Module 1.1: Kernel & Architecture	Kernel vs userspace, modules, why containers share kernels	140–170 min
1.2	Module 1.2: Processes & systemd	PIDs, process lifecycle, signals, systemctl, units	90–120 min
1.3	Module 1.3: Filesystem Hierarchy	/etc, /var, /proc, /sys, inodes, mount points	80–110 min
1.4	Module 1.4: Users & Permissions	UIDs, groups, rwx, setuid, sudo, least privilege	80–110 min

These are planning estimates copied from the four module headers, not measured learner completion times. Their arithmetic gives an aggregate range of 390–510 minutes (about 6 hours 30 minutes–8 hours 30 minutes); individual setup, reading, and practice time will vary.

Why This Section Matters

Every single thing you do on Linux touches these concepts:

Running a container? The kernel provides process isolation
Debugging a crash? Understanding processes helps you investigate
Checking configuration? You need to know where files live
Running kubectl? Permissions determine what you can do

Prerequisites

Everyday Use — Shell commands, navigation, process tools, and daily workflows

Key Takeaways

After completing this section, you’ll understand:

How the Linux kernel manages everything (and why containers share it)
What processes are and how they’re managed by systemd
Where everything lives in Linux (and why it’s organized that way)
How users and permissions protect systems