Technology · Ebook

KCL: Typed Configuration for the Cloud-Native World

by Shriira Press

KCL is an open-source configuration and policy language, a CNCF sandbox project, designed to tame the sprawl of YAML and templating that infrastructure teams wrestle with every day. Inspired by Python's readability but built around static typing, immutability, and constraint validation, it lets you describe configuration as schemas the compiler checks before anything reaches a cluster. This book starts with the problem KCL solves, tours its syntax, then goes deep on schemas, the type system, and validation through check blocks and rules. It covers configuration abstraction and merge operators, the OCI-based package manager and module system, KCL's rich Kubernetes integration with CRDs, Helm, and Kustomize, and finally the toolchain, multi-language SDKs, and the KusionStack platform that make KCL pay off in production.

Contents

1. 1Preface
2. 2Chapter 1 — What KCL Is
3. 3Chapter 2 — A Tour of the Language
4. 4Chapter 3 — Schemas and the Type System
5. 5Chapter 4 — Validation and Policy
6. 6Chapter 5 — Configuration Abstraction and Merging
7. 7Chapter 6 — Packages and Modules
8. 8Chapter 7 — KCL and Kubernetes
9. 9Chapter 8 — KCL in Practice