athenix/docs/USER_CONFIGURATION.md

User Configuration Guide

Comprehensive guide to managing user accounts in Athenix.

Table of Contents

• Overview
• Quick Start
• Defining Users
• Enabling Users on Hosts
• External User Configurations
• Password Management
• SSH Keys
• User Groups
• Examples

Overview

User accounts are defined in users.nix but are not enabled by default. Each host must explicitly enable users in inventory.nix.

Always-enabled users:

• root - System administrator (enable: true)
• engr-ugaif - Innovation Factory default account (enable: true)

All other users are disabled by default and must be explicitly enabled per-host.

Quick Start

1. Define User in users.nix

athenix.users.myuser = {
  description = "John Doe";
  extraGroups = [ "wheel" "networkmanager" ];
  shell = pkgs.zsh;
  hashedPassword = "$6$...";  # Generate with: mkpasswd -m sha-512
  opensshKeys = [ "ssh-ed25519 AAAA..." ];
};

2. Enable on Hosts in inventory.nix

nix-laptop = {
  devices = 5;
  overrides.athenix.users.myuser.enable = true;
};

3. Users can now log in

Users defined and enabled this way are automatically created on the system.

Defining Users

Define users in users.nix under athenix.users:

Inline User Definition

athenix.users.myuser = {
  description = "My Full Name";
  extraGroups = [ "wheel" "networkmanager" ];
  shell = pkgs.zsh;
  hashedPassword = "$6$...";
  opensshKeys = [ "ssh-ed25519 AAAA..." ];
  useZshTheme = true;
  useNvimPlugins = true;
};

External User Configuration

Reference an external Git repository (recommended for personal dotfiles):

athenix.users.myuser.external = builtins.fetchGit {
  url = "https://git.factory.uga.edu/username/dotfiles";
  rev = "abc123...";  # Pin to specific commit
};

The external repository should contain:

• user.nix (required) - User account options AND home-manager configuration
• nixos.nix (optional) - System-level configuration

See External User Configurations section below.

User Account Options

description

Full name or description of the user.

Type: String

athenix.users.myuser.description = "John Doe";

extraGroups

Additional Unix groups for the user. Default is empty.

Type: List of strings

Common groups:

• "wheel" - Sudo access
• "networkmanager" - Network configuration
• "docker" - Docker and Podman access
• "video" - Video device access (GPU, displays)
• "audio" - Audio device access
• "input" - Input devices (keyboards, mice)
• "kvm" - KVM virtual machine access
• "libvirtd" - Libvirt daemon access

athenix.users.myuser.extraGroups = [
  "wheel"
  "networkmanager"
  "docker"
  "video"
];

shell

Login shell for the user.

Type: Package

Default: pkgs.bash

athenix.users.myuser.shell = pkgs.zsh;
# or
athenix.users.myuser.shell = pkgs.fish;

hashedPassword

Password hash for the user. Use ! to disable password login (SSH keys only).

Type: String (SHA-512 hash)

Generation:

# Generate a hashed password
mkpasswd -m sha-512

# Or interactively
mkpasswd -m sha-512 -c

athenix.users.myuser.hashedPassword = "$6$...";

# Disable password login (require SSH keys)
athenix.users.myuser.hashedPassword = "!";

opensshKeys

SSH public keys for remote access. Users without SSH keys require password login.

Type: List of strings

athenix.users.myuser.opensshKeys = [
  "ssh-ed25519 AAAA... user@laptop"
  "ssh-rsa AAAA... user@desktop"
];

Getting your SSH public key:

# Print your public key
cat ~/.ssh/id_ed25519.pub

# Generate a new key if needed
ssh-keygen -t ed25519 -C "user@host"

useZshTheme

Apply system Zsh theme configuration to this user (if using Zsh as shell).

Type: Boolean

Default: true

athenix.users.myuser.useZshTheme = true;

useNvimPlugins

Apply system Neovim configuration and plugins to this user.

Type: Boolean

Default: true

athenix.users.myuser.useNvimPlugins = true;

Enabling Users on Hosts

Users are not enabled by default. Enable them in inventory.nix:

Enable on All Devices in a Group

nix-laptop = {
  devices = 5;
  overrides.athenix.users.myuser.enable = true;
};

Enable on Specific Devices

nix-desktop = {
  devices = {
    "1".athenix.users.admin.enable = true;
    "2".athenix.users.staff.enable = true;
    "3".athenix.users.staff.enable = true;
  };
};

Enable Multiple Users

nix-laptop = {
  devices = 5;
  overrides = {
    athenix.users.student.enable = true;
    athenix.users.teacher.enable = true;
  };
};

Using athenix.forUser Convenience

Quick setup for single-user systems (especially WSL):

nix-wsl = {
  devices = {
    "alice".athenix.forUser = "alice-uga";
    "bob".athenix.forUser = "bob-uga";
  };
};

This automatically enables the user and sets it as the default WSL user.

External User Configurations

External user configurations (dotfiles) allow users to maintain their own home-manager setup in separate repositories.

Repository Structure

my-dotfiles/
├── user.nix      # Required: User options + home-manager config
├── nixos.nix     # Optional: System-level configuration
└── config/       # Optional: Your actual dotfiles
    ├── bashrc
    ├── zshrc
    ├── vimrc
    └── ...

user.nix (Required)

This file must provide BOTH user account options AND home-manager configuration:

{ inputs, ... }:
{ config, lib, pkgs, osConfig ? null, ... }:
{
  # ========== User Account Configuration ==========
  # These options define the user account itself
  athenix.users.myusername = {
    description = "My Full Name";
    extraGroups = [ "wheel" "docker" "networkmanager" ];
    shell = pkgs.zsh;
    hashedPassword = "!";  # SSH keys only
    opensshKeys = [
      "ssh-ed25519 AAAA... user@host"
    ];
    useZshTheme = true;
    useNvimPlugins = true;
  };

  # ========== Home Manager Configuration ==========
  # User environment, packages, and dotfiles
  
  home.packages = with pkgs; [
    vim
    ripgrep
    fzf
  ] ++ lib.optional (osConfig.athenix.sw.type or null == "desktop") firefox;

  programs.git = {
    enable = true;
    userName = "My Name";
    userEmail = "me@example.com";
    extraConfig = {
      init.defaultBranch = "main";
      core.editor = "vim";
    };
  };

  programs.zsh = {
    enable = true;
    initExtra = ''
      # Your Zsh configuration
    '';
  };

  # Manage dotfiles
  home.file.".config/zshrc".source = ./config/zshrc;
  home.file.".config/bashrc".source = ./config/bashrc;
  home.file.".vimrc".source = ./config/vimrc;
}

nixos.nix (Optional)

System-level configuration for this user (rarely needed):

{ inputs, ... }:
{ config, lib, pkgs, ... }:
{
  # System-level configuration for this user
  users.users.myusername.extraGroups = [ "docker" ];
  environment.systemPackages = [ pkgs.docker ];
}

Using External User Configuration

In users.nix:

athenix.users.myuser.external = builtins.fetchGit {
  url = "https://git.factory.uga.edu/username/dotfiles";
  rev = "abc123...";  # Pin to specific commit
};

Then enable on hosts in inventory.nix:

nix-laptop = {
  devices = 5;
  overrides.athenix.users.myuser.enable = true;
};

External Module Parameters

The user.nix module receives:

• inputs - All flake inputs (nixpkgs, home-manager, etc.)
• config - Home-manager configuration
• lib - Nixpkgs library functions
• pkgs - Package set
• osConfig - OS-level configuration (read-only, can be used for conditional setup)

Creating External User Configuration

Use the template:

nix flake init -t git+https://git.factory.uga.edu/UGA-Innovation-Factory/athenix.git#user

Password Management

Generate Password Hash

# Interactive (won't echo)
mkpasswd -m sha-512 -c

# From string
echo "mypassword" | mkpasswd -m sha-512 -s

Disable Password Login

Set hashedPassword = "!" and provide SSH keys:

athenix.users.myuser = {
  description = "SSH-only user";
  hashedPassword = "!";
  opensshKeys = [ "ssh-ed25519 AAAA..." ];
};

Update User Password on Running System

# As the user
passwd

# As root (to change another user's password)
sudo passwd username

SSH Keys

Add SSH Keys to a User

athenix.users.myuser.opensshKeys = [
  "ssh-ed25519 AAAA... user@laptop"
  "ssh-ed25519 BBBB... user@desktop"
];

Get Your SSH Public Key

# Display your public key
cat ~/.ssh/id_ed25519.pub

# Or for RSA
cat ~/.ssh/id_rsa.pub

Generate New SSH Key

# Ed25519 (recommended)
ssh-keygen -t ed25519 -C "user@host"

# RSA (older systems)
ssh-keygen -t rsa -b 4096 -C "user@host"

User Groups

wheel

Allows passwordless sudo access.

athenix.users.myuser.extraGroups = [ "wheel" ];

networkmanager

Configure network connections (requires networkmanager to be enabled):

athenix.users.myuser.extraGroups = [ "networkmanager" ];

docker

Access Docker daemon (must have Docker enabled on system):

athenix.users.myuser.extraGroups = [ "docker" ];

video and audio

Access GPU and audio devices:

athenix.users.myuser.extraGroups = [ "video" "audio" ];

Examples

Example 1: Basic Lab User

# users.nix
athenix.users.student = {
  description = "Student Account";
  extraGroups = [ "networkmanager" ];
  shell = pkgs.bash;
  hashedPassword = "$6$...";
  opensshKeys = [];  # Password login only
};

# inventory.nix
nix-laptop = {
  devices = 20;
  overrides.athenix.users.student.enable = true;
};

Example 2: Developer with SSH Keys

# users.nix
athenix.users.developer = {
  description = "Developer";
  extraGroups = [ "wheel" "docker" "networkmanager" ];
  shell = pkgs.zsh;
  hashedPassword = "!";
  opensshKeys = [
    "ssh-ed25519 AAAA... dev@laptop"
  ];
  useZshTheme = true;
  useNvimPlugins = true;
};

# inventory.nix
nix-desktop = {
  devices = 3;
  overrides.athenix.users.developer.enable = true;
};

Example 3: WSL User with Dotfiles

# users.nix
athenix.users.alice.external = builtins.fetchGit {
  url = "https://git.factory.uga.edu/alice/dotfiles";
  rev = "abc123...";
};

# inventory.nix
nix-wsl = {
  devices = {
    "alice".athenix.forUser = "alice-uga";
  };
};

Example 4: Multiple Users on Single System

# users.nix
athenix.users = {
  admin = {
    description = "System Administrator";
    extraGroups = [ "wheel" ];
    shell = pkgs.bash;
    hashedPassword = "!";
    opensshKeys = [ "ssh-ed25519 AAAA..." ];
  };
  guest = {
    description = "Guest User";
    extraGroups = [];
    shell = pkgs.bash;
    hashedPassword = "$6$...";
  };
};

# inventory.nix
nix-desktop = {
  devices = {
    "admin-station" = {
      athenix.users.admin.enable = true;
    };
    "guest-station" = {
      athenix.users.guest.enable = true;
    };
  };
};

See Also

• INVENTORY.md - Host configuration

• NAMESPACE.md - All configuration options

• EXTERNAL_MODULES.md - External modules in detail

• README.md - Main documentation external = builtins.fetchGit { ... }; # External user module (see below)

  === Theme Integration ===

  useZshTheme = true; # Apply system Zsh theme (default: true) useNvimPlugins = true; # Apply system Neovim config (default: true)

  === System Enablement ===

  enable = false; # Enable on this system (set in inventory.nix) };

## External User Configurations

Users can maintain their dotfiles and home-manager configuration in separate Git repositories.

### Basic External Configuration

In `users.nix`:

```nix
myuser = {
  # Basic options can be set here OR in the external module's user.nix
  description = "My Name";
  extraGroups = [ "wheel" ];
  hashedPassword = "$6$...";
  
  # Point to external configuration repository
  external = builtins.fetchGit {
    url = "https://git.factory.uga.edu/username/dotfiles";
    rev = "abc123...";  # Pin to specific commit
  };
};

External Repository Structure

dotfiles/
├── user.nix     # Required: User options AND home-manager config
├── nixos.nix    # Optional: System-level configuration
└── config/      # Optional: Your dotfiles
    ├── bashrc
    ├── vimrc
    └── ...

At least user.nix should be present for a functional user module.

user.nix (required):

{ inputs, ... }:
{ config, lib, pkgs, osConfig ? null, ... }:
{
  # ========== User Account Configuration ==========
  # These options define the user account itself
  athenix.users.myuser = {
    description = "My Full Name";
    extraGroups = [ "wheel" "docker" ];
    shell = pkgs.zsh;
    hashedPassword = "!";
    opensshKeys = [
      "ssh-ed25519 AAAA... user@host"
    ];
    useZshTheme = true;
    useNvimPlugins = true;
  };

  # ========== Home Manager Configuration ==========
  # User environment, packages, and dotfiles
  
  home.packages = with pkgs; [
    vim
    ripgrep
  ] ++ lib.optional (osConfig.athenix.sw.type or null == "desktop") firefox;

  programs.git = {
    enable = true;
    userName = "My Name";
    userEmail = "me@example.com";
    extraConfig = {
      init.defaultBranch = "main";
    };
  };
  
  home.file.".bashrc".source = ./config/bashrc;
}

nixos.nix (optional):

{ inputs, ... }:
{ config, lib, pkgs, ... }:
{
  # System-level configuration
  users.users.myusername.extraGroups = [ "docker" ];
  environment.systemPackages = [ pkgs.docker ];
}

What External Modules Receive

In user.nix:

• inputs - Flake inputs (nixpkgs, home-manager, etc.)
• config - Configuration (NixOS or home-manager depending on import context)
• lib - Nixpkgs library functions
• pkgs - Package set
• osConfig - (home-manager context only) OS-level configuration

How External Modules Are Loaded

The user.nix module serves a dual purpose and is imported in two contexts:

1. NixOS Module Context (User Options): The module is imported as a NixOS module where athenix.users.<username> options are read to define the user account (description, shell, groups, SSH keys, etc.). These options override any defaults set in users.nix.

2. Home-Manager Context: The same module is imported into home-manager where home.*, programs.*, and services.* options configure the user's environment, packages, and dotfiles.

Key insight: A single user.nix file contains both account configuration AND home environment configuration. The system automatically imports it in the appropriate contexts.

Example: The user account options (like shell, extraGroups) are read during NixOS evaluation, while home-manager options (like home.packages, programs.git) are used when building the user's home environment.

In nixos.nix:

• inputs - Flake inputs
• config - NixOS configuration
• lib - Nixpkgs library functions
• pkgs - Package set

Alternative Configuration Methods

Local path (for testing):

external = /home/username/dev/dotfiles;

Note: User options can be set in users.nix OR in the external module's user.nix file. For custom packages and environment configuration without external modules, create a local module and reference it with extraImports.

Create User Template

nix flake init -t git+https://git.factory.uga.edu/UGA-Innovation-Factory/athenix.git#user

See templates/user/README.md for complete template.

Enabling Users on Hosts

Users must be explicitly enabled on each host in inventory.nix.

Method 1: Enable in Overrides (All Devices)

nix-laptop = {
  devices = 5;
  overrides = {
    athenix.users.student.enable = true;  # All 5 laptops get this user
  };
};

Method 2: Enable per Device

nix-desktop = {
  devices = {
    "1".athenix.users.alice.enable = true;
    "2".athenix.users.bob.enable = true;
    "3" = {
      athenix.users.alice.enable = true;
      athenix.users.bob.enable = true;
    };
  };
};

Method 3: Convenience Option (athenix.forUser)

Quick setup for single-user systems:

nix-wsl = {
  devices = {
    "alice".athenix.forUser = "alice-user";  # Automatically enables alice-user
    "bob".athenix.forUser = "bob-user";
  };
};

This is equivalent to athenix.users.alice-user.enable = true.

Password Management

Generate Hashed Password

mkpasswd -m sha-512
# Enter password when prompted
# Copy the output hash

In users.nix

myuser = {
  hashedPassword = "$6$rounds=656000$...";  # Paste hash here
};

Disable Password Login

myuser = {
  hashedPassword = "!";  # Locks password, SSH key only
  opensshKeys = [ "ssh-ed25519 ..." ];
};

Change Password Later

On the system:

sudo passwd myuser

Or regenerate hash and update users.nix.

SSH Keys

Adding SSH Keys

myuser = {
  opensshKeys = [
    "ssh-ed25519 AAAAC3Nza... user@laptop"
    "ssh-rsa AAAAB3NzaC1... user@desktop"
  ];
};

Generate SSH Key

ssh-keygen -t ed25519 -C "user@hostname"
cat ~/.ssh/id_ed25519.pub  # Copy this

Multiple Keys

Users can have multiple SSH keys for different machines:

opensshKeys = [
  "ssh-ed25519 ... user@work-laptop"
  "ssh-ed25519 ... user@home-desktop"  
  "ssh-ed25519 ... user@tablet"
];

Examples

Basic User

student = {
  description = "Student Account";
  extraGroups = [ "networkmanager" ];
  shell = pkgs.bash;
  hashedPassword = "$6$...";
};

Admin User with SSH

admin = {
  description = "System Administrator";
  extraGroups = [ "wheel" "networkmanager" "docker" ];
  shell = pkgs.zsh;
  hashedPassword = "$6$...";
  opensshKeys = [
    "ssh-ed25519 AAAA... admin@laptop"
  ];
};

User with External Configuration

developer = {
  description = "Developer";
  extraGroups = [ "wheel" "docker" ];
  shell = pkgs.zsh;
  hashedPassword = "$6$...";
  external = builtins.fetchGit {
    url = "https://git.factory.uga.edu/username/dotfiles";
    rev = "abc123def456...";
  };
};

WSL User

wsl-user = {
  description = "WSL User";
  extraGroups = [ "wheel" ];
  shell = pkgs.zsh;
  hashedPassword = "$6$...";
  external = builtins.fetchGit {
    url = "https://git.factory.uga.edu/username/dotfiles";
    rev = "abc123...";
  };
};

Enable in inventory.nix:

nix-wsl = {
  devices."my-wsl".athenix.forUser = "wsl-user";
};

User Without System Themes

For users who want complete control over their shell/editor:

poweruser = {
  description = "Power User";
  extraGroups = [ "wheel" ];
  shell = pkgs.zsh;
  hashedPassword = "$6$...";
  useZshTheme = false;      # Don't apply system theme
  useNvimPlugins = false;   # Don't apply system nvim config
  external = builtins.fetchGit {
    url = "https://github.com/username/custom-dotfiles";
    rev = "abc123...";
  };
};

Theme Integration

System Zsh Theme

When useZshTheme = true (default), the system applies:

• Oh My Posh with custom theme
• History substring search
• Vi mode (for non-root users)
• Zsh plugins (zplug)

Disable if you want full control in your dotfiles.

System Neovim Config

When useNvimPlugins = true (default), the system applies:

• LazyVim distribution
• TreeSitter parsers
• Language servers

Disable if you want to configure Neovim yourself.

Troubleshooting

User Can't Login

Check if enabled on host:

nix eval .#nixosConfigurations.nix-laptop1.config.athenix.users.myuser.enable

Check if user exists:

# On the system
id myuser

SSH Key Not Working

Check key in configuration:

nix eval .#nixosConfigurations.nix-laptop1.config.users.users.myuser.openssh.authorizedKeys.keys

Verify key format:

• Should start with ssh-ed25519, ssh-rsa, or ssh-dss
• Should be all on one line
• Should end with comment (optional)

External Config Not Loading

Check repository access:

git ls-remote https://git.factory.uga.edu/username/dotfiles

Verify structure:

• Must have user.nix at repository root
• nixos.nix is optional
• Check file permissions

Test with local path first:

external = /path/to/local/dotfiles;

See Also

• EXTERNAL_MODULES.md - External module guide
• INVENTORY.md - Host configuration guide
• NAMESPACE.md - Configuration options reference
• templates/user/ - User module template
• README.md - Main documentation