Technology · Ebook

Flatcar Container Linux: The Immutable Container Host

by Shriira Press

Flatcar Container Linux is a minimal, immutable, container-optimized Linux distribution — a purpose-built host OS for running containers, and the community successor to CoreOS Container Linux. This free book teaches it from the ground up: the container-host problem and what Flatcar is, the container host and immutable infrastructure (plus the CoreOS heritage), Flatcar's minimal immutable design (the read-only filesystem), provisioning with Ignition (declarative first-boot config and Butane), automatic atomic updates (the dual-partition scheme, rollback, channels), running containers on Flatcar (the runtime, systemd, everything-is-a-container), Flatcar and Kubernetes (the ideal node OS, immutable nodes), update management at fleet scale (reboot coordination, FLUO/Kured, Nebraska), security (minimal attack surface, immutability, hardening), and operating Flatcar in practice across environments. Ten focused chapters with clear diagrams that demystify the immutable container-host model — a minimal, self-updating, secure OS for running containers reliably at scale.

Contents

1. 1Preface
2. 2Chapter 1 — What Flatcar Container Linux Is
3. 3Chapter 2 — The Container Host and Immutable Infrastructure
4. 4Chapter 3 — The Minimal, Immutable Design
5. 5Chapter 4 — Provisioning with Ignition
6. 6Chapter 5 — Automatic Atomic Updates
7. 7Chapter 6 — Running Containers on Flatcar
8. 8Chapter 7 — Flatcar and Kubernetes
9. 9Chapter 8 — Update Management at Fleet Scale
10. 10Chapter 9 — Security
11. 11Chapter 10 — Operating Flatcar in Practice