How declarative state, a careful verification step, and an automatic rollback turn host networking from a fragile art into a repeatable practice — on bare metal and across Kubernetes clusters.

Welcome to NMState: Declarative Host Networking.

NMState is a library and command-line tool that manages a host's network the way good infrastructure tooling manages everything else: you describe the network you want as a piece of structured data, and the tool makes the system match it. Instead of issuing a sequence of brittle commands to bring up a bond, stack a VLAN on top, and attach it to a bridge, you write a YAML document describing the desired interfaces, addresses, routes, and DNS, and hand it to nmstatectl, which drives NetworkManager to realize that state — verifying the result and rolling back automatically if anything goes wrong. This book starts from the problem of imperative network configuration and the risk of locking yourself out of a remote box, then builds up the desired-state model and schema, the verify-and-rollback transaction that makes remote changes safe, and the rich catalogue of interface types NMState understands. From there it crosses into Kubernetes, where the kubernetes-nmstate operator turns the same engine into cluster-native custom resources — NodeNetworkConfigurationPolicy, NodeNetworkConfigurationEnactment, and NodeNetworkState — so you can configure node networking declaratively at scale. A closing chapter gathers the operational practices that keep all of this dependable in production.

This title is part of the ShriIra library and is free to read in full, right here — our small contribution to making world-class knowledge easy to reach.

A note on reading it: open the Contents menu at the top of the reader to jump between chapters, use the Aa menu to set a comfortable text size, theme (light, sepia, or night), and single- or two-page layout. Your place is saved automatically, so you can always pick up where you left off.

We hope it serves you well.

— Shriira Press

Contents

1. Chapter 1 — The Trouble with Configuring Networks
2. Chapter 2 — The Desired-State Model
3. Chapter 3 — The State Schema
4. Chapter 4 — Verification, Checkpoints, and Rollback
5. Chapter 5 — Interface Types and Real Topologies
6. Chapter 6 — NMState on Kubernetes
7. Chapter 7 — NMState in Practice