Aἰθήρ

[Aither] as a whole neither came into being nor admits of destruction, but is one and eternal, with no end or beginning of its total duration, containing and embracing in itself the infinity of time ...

— Aristotle, On the Heavens ¹

Aether is a fully automated web server configured via pure and declarative package management, powered by NixOS. This allows for all aspects of the server's operation, including config files, software dependencies, and site content to be deployed and provisioned automatically.

In short, it's my personal web server. It's also a NixOS codebase to support that server, designed for generic use in other configurations.

Modules

As with all good NixOS configurations, Aether is split into modules. Each is stored as a subdirectory of the modules/ directory and defines an specific function of the server.

Modules are publicly exposed by this flake as nixosModules.<name>, and can be imported to activate their functionality. Any number of modules can be imported independently, and the special nixosModules.all flake output can be used to import every module at once.

Some modules have options that can be used to configure their effects. If a module has options, they can be found in the options.nix file inside the module directory. More general options used by multiple modules are documented in modules/options.nix.

Module Checklist

• basic - Basic Internet support
• ssh - SSH support
• site - Static site hosting
• fail2ban - IP moderation
• forgejo - Code forge
• mail - Mail server
• cachix - Nix build caching
• backup - Automated backup system

Deployment

Aether is designed to separate individual machine details from the abstract specification of the system, allowing for its code to be used for many different types of system. This is handled using deployments in the deploy/ directory.

Each deployment module is exposed as nixosModules.deploy-<name>. Only one deployment should be imported; if Aether detects that more than one is imported, it will prevent the configuration from building.

Currently, I deploy Aether physically to a Raspberry Pi 5 running a modified UEFI bootloader to provide Linux support. The NixOS code for this can be found in deploy/rpi5/, and it is exposed as nixosModules.deploy-rpi5.

[!IMPORTANT] A complete rewrite of the deployment system using NixOps 4 is planned once that project is stabilized. This may result in breaking changes to Aether's public interface.

External Usage

If you use NixOS and are interested in any of these modules, you can import them for your own config!

Flake-Based Configuration

Add this repository as a flake input:

{
  inputs.aether.url = "https://git.tokinanpa.dev/toki/aether/archive/main.tar.gz";
}

Aether's modules can then be accessed as flake outputs. In particular, the specialArgs parameter can be used to expose the modules in your configuration:

nixpkgs.lib.nixosSystem {
  specialArgs = {
    aether = aether.nixosModules;
  };
  modules = [
    ./config.nix
  ];
}

# -- config.nix --
{ aether, ... }:
{
  imports = with aether; [
    # Deployment
    deploy-rpi5
    # Modules
    forgejo
    ssh
  ];

  # Required module option
  aether.domain = "...";
}

For a more complete example of how to use Aether modules, my personal server config can be found in the aether/ directory.

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1. Adapted from Book II.1. ↩︎