Technology · Ebook

Stacker: Reproducible, Unprivileged OCI Image Builds

by Shriira Press

Stacker is a CNCF Sandbox project that builds Open Container Initiative images from a declarative stacker.yaml file, without a background daemon and without requiring root. It runs as a single binary that uses Linux user namespaces and unprivileged overlay mounts to assemble images inside a hermetically sealed environment, caches every input so only what changed is rebuilt, and writes standard OCI image layouts ready for any registry or runtime. This book covers the problem Stacker solves, the anatomy of a stacker file, the rootless build engine, layers and content-addressed caching, the OCI layout it produces, the command-line workflow, and its place in a signed supply chain alongside zot and cosign.

Contents

1. 1Preface
2. 2Chapter 1 — Why Build Images Differently
3. 3Chapter 2 — The Stacker File
4. 4Chapter 3 — Inside the Build Engine
5. 5Chapter 4 — Layers, Imports, and the Cache
6. 6Chapter 5 — The OCI Image Layout
7. 7Chapter 6 — The Command-Line Workflow
8. 8Chapter 7 — Stacker in Practice