57 lines
1.4 KiB
Markdown
57 lines
1.4 KiB
Markdown
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# NixOS Configurations
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This note covers `21-nixos-configurations/`, which defines a full `nixosConfigurations` output.
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---
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## 1. Module Versus Configuration
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`04-nixos-module/` shows a reusable module. This example shows the next layer up: a full system definition built with `nixpkgs.lib.nixosSystem`.
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The local `module.nix` still matters, but now it is only one input into a named machine configuration.
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---
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## 2. What the Flake Exposes
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The key output is:
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- `nixosConfigurations.demo`
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That is the shape other commands expect when you build, inspect, or deploy a NixOS system from a flake.
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---
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## 3. Why the Example Sets Boot and File System Options
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Even a small NixOS configuration needs a few system-level settings to evaluate cleanly as a full configuration.
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This example sets:
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- a host name,
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- a root file system,
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- a boot loader device, and
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- `system.stateVersion`.
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Those settings are minimal, and they keep the example focused on flake structure rather than real machine setup.
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---
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## 4. What the Check Verifies
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The check reads values from the evaluated configuration and compares them with the expected host name and `/etc` file contents.
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That proves the configuration merges correctly without turning the example into a deployment workflow.
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---
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## 5. Commands to Try
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```bash
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cd 21-nixos-configurations
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nix flake show
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nix eval .#nixosConfigurations.demo.config.networking.hostName --raw
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nix flake check
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```
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