# How to add machines

Machines can be added using the following methods

- Editing nix expressions in flake.nix (i.e. via `clan-core.lib.clan`)
- Editing machines/`machine_name`/configuration.nix (automatically included if it exists)
- `clan machines create` (imperative)

See the complete [list](../../guides/more-machines.md#automatic-registration) of auto-loaded files.

## Create a machine

=== "flake.nix (flake-parts)"

    ```{.nix hl_lines=12-15}
    {
        inputs.clan-core.url = "https://git.clan.lol/clan/clan-core/archive/main.tar.gz";
        inputs.nixpkgs.follows = "clan-core/nixpkgs";
        inputs.flake-parts.follows = "clan-core/flake-parts";
        inputs.flake-parts.inputs.nixpkgs-lib.follows = "clan-core/nixpkgs";

        outputs =
            inputs@{ flake-parts, ... }:
            flake-parts.lib.mkFlake { inherit inputs; } {
                imports = [ inputs.clan-core.flakeModules.default ];
                clan = {
                    inventory.machines = {
                        # Define a machine
                        jon = { };
                    };
                };

                systems = [
                    "x86_64-linux"
                    "aarch64-linux"
                    "x86_64-darwin"
                    "aarch64-darwin"
                ];
        };
    }
    ```

=== "flake.nix (classic)"

    ```{.nix hl_lines=11-14}
    {
        inputs.clan-core.url = "https://git.clan.lol/clan/clan-core/archive/main.tar.gz";
        inputs.nixpkgs.follows = "clan-core/nixpkgs";

        outputs =
            { self, clan-core, ... }:
            let
                clan = clan-core.lib.clan {
                    inherit self;

                    inventory.machines = {
                        # Define a machine
                        jon = { };
                    };
                };
            in
            {
                inherit (clan.config)
                    nixosConfigurations
                    nixosModules
                    clanInternals
                    darwinConfigurations
                    darwinModules
                    ;
            };
    }
    ```

=== "CLI (imperative)"

    ```sh
    clan machines create jon
    ```

    The imperative command might create a machine folder in `machines/jon`
    And might persist information in `inventory.json`


### Configuring a machine

!!! Note
    The option: `inventory.machines.<name>` is used to define metadata about the machine
    That includes for example `deploy.targethost` `machineClass` or `tags`

    The option: `machines.<name>` is used to add extra *nixosConfiguration* to a machine

```{.nix .annotate title="flake.nix" hl_lines="3-13 18-22"}
clan = {
    inventory.machines = {
        jon = {
            # Define targetHost here
            # Required before deployment
            deploy.targetHost = "root@jon"; # (1)
            # Define tags here
            tags = [ ];
        };
        sara = {
            deploy.targetHost = "root@sara";
            tags = [ ];
        };
    };
    # Define additional nixosConfiguration here
    # Or in /machines/jon/configuration.nix (autoloaded)
    machines = {
        jon = { config, pkgs, ... }: {
            users.users.root.openssh.authorizedKeys.keys = [
                "ssh-ed25519 AAAAC3NzaC..." # elided (2)
            ];
        };
    };
}
```

1. It is required to define a *targetHost* for each machine before deploying. Best practice has been, to use the zerotier ip/hostname or the ip from the from overlay network you decided to use.
2. Add your *ssh key* here - That will ensure you can always login to your machine via *ssh* in case something goes wrong.

### (Optional): Renaming Machine

For renaming jon to your own machine name, you can use the following command:

```
git mv ./machines/jon ./machines/newname
```

Note that our clan lives inside a git repository.
Only files that have been added with `git add` are recognized by `nix`.
So for every file that you add or rename you also need to run:

```
git add ./path/to/my/file
```

### (Optional): Removing a Machine

If you only want to setup a single machine at this point, you can delete `sara` from `flake.nix` as well as from the machines directory:

```
git rm -rf ./machines/sara
```