Security Hardening

Killercoda lab progress 0/4 completed

Interactive labs, not module completion

Protecting Linux systems and containers through kernel-level security.

Overview

Security isn’t just firewalls—it’s defense in depth. This section covers the Linux security mechanisms that protect containers and hosts: kernel tuning, mandatory access controls (AppArmor, SELinux), and system call filtering (seccomp).

Modules

#	Module	Description	Time
4.1	Kernel Hardening & sysctl	Network stack, memory protection, kernel parameters	70–100 min
4.2	AppArmor Profiles	Mandatory access control, profile modes, K8s integration	80–110 min
4.3	SELinux Contexts	Policies, contexts, enforcing mode, troubleshooting	80–110 min
4.4	seccomp Profiles	System call filtering, custom profiles	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 310–430 minutes (about 5 hours 10 minutes–7 hours 10 minutes); individual setup, reading, and practice time will vary.

Why This Section Matters

Linux security features are directly used by Kubernetes:

sysctl — Node hardening, network security
AppArmor — Pod security profiles (Ubuntu/Debian)
SELinux — Pod security profiles (RHEL/CentOS)
seccomp — System call filtering for containers

CKS (Certified Kubernetes Security Specialist) specifically tests these topics.

Prerequisites

Container Primitives — Especially capabilities & LSMs
Networking — For network hardening

Key Takeaways

After completing this section, you’ll understand:

How to harden Linux kernels via sysctl
How AppArmor profiles restrict application behavior
How SELinux provides mandatory access control
How seccomp filters dangerous system calls