Create Raspberry Pi Host

Create a new Raspberry Pi host for the RPC (Raspberry Pi Cluster).

Parameter Handling

If parameters are missing from $ARGUMENTS, use mcp_question to gather them:

mcp_question({
  questions: [
    {
      question: "Which Raspberry Pi model is this?",
      header: "Model",
      options: [
        { label: "Pi 5 (Recommended)", description: "Raspberry Pi 5" },
        { label: "Pi 4", description: "Raspberry Pi 4" }
      ]
    },
    {
      question: "What NATO phonetic name for this cluster member?",
      header: "Name",
      options: [
        { label: "alpha", description: "First letter" },
        { label: "bravo", description: "Second letter" },
        { label: "charlie", description: "Third letter" },
        { label: "delta", description: "Fourth letter" },
        { label: "echo", description: "Fifth letter" },
        { label: "foxtrot", description: "Sixth letter" },
        { label: "golf", description: "Seventh letter" },
        { label: "hotel", description: "Eighth letter" },
        { label: "Enter other...", description: "india, juliet, kilo, lima, etc." }
      ]
    }
  ]
})

Expected $ARGUMENTS format: rpc-<model>-<name>

• Example: rpc-5-alpha (Pi 5, first member)
• Example: rpc-4-echo (Pi 4, fifth member)

Alternative format: <model> <name> which will be combined to rpc-<model>-<name>

• Example: 5 india → rpc-5-india

Naming Convention

• rpc = Raspberry Pi Cluster prefix
• <model> = Pi model: 4 for Pi 4, 5 for Pi 5
• <name> = NATO phonetic alphabet (alpha, bravo, charlie, delta, echo, foxtrot, golf, hotel, india, juliet, kilo, lima, mike, november, oscar, papa, quebec, romeo, sierra, tango, uniform, victor, whiskey, xray, yankee, zulu)

Steps

1. Parse and validate the hostname from $ARGUMENTS

- Must match pattern rpc-[45]-(alpha|bravo|charlie|delta|echo|foxtrot|golf|hotel|india|juliet|kilo|lima|mike|november|oscar|papa|quebec|romeo|sierra|tango|uniform|victor|whiskey|xray|yankee|zulu) - Extract the model number (4 or 5) - Extract the member name (NATO phonetic alphabet) - If invalid, ask the user to provide a valid hostname

1. Check if host already exists:

``bash ls hosts/$HOSTNAME 2>/dev/null `` If exists, warn user and ask to confirm overwrite

1. Create directory structure:

``bash mkdir -p hosts/$HOSTNAME/users/jmeskill ``

1. Create configuration.nix at hosts/$HOSTNAME/configuration.nix:

```nix { flake, inputs, lib, pkgs, ... }: { imports = [ flake.nixosModules.default flake.nixosModules.server

./hardware-configuration.nix ];

networking.hostName = "$HOSTNAME";

# Use the recommended "kernel" bootloader for Raspberry Pi boot.loader.raspberryPi.bootloader = "kernel";

# Resolve nixpkgs registry conflict between main nixpkgs and nixos-raspberrypi's nixpkgs nix.registry.nixpkgs.to = lib.mkForce { type = "path"; path = inputs.nixpkgs.outPath; };

# Disable UPS monitoring (no UPS connected to this Pi) power.ups.enable = lib.mkForce false;

# Enable SSH for remote access services.openssh = { enable = true; settings = { PasswordAuthentication = false; PermitRootLogin = "prohibit-password"; }; };

# User configuration users.users.jmeskill = { uid = 1000; isNormalUser = true; description = "Jade Meskill"; extraGroups = ["wheel"]; openssh.authorizedKeys.keys = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIL8rjXP/sjewv6kM1aTtNWkVZKJpZvIAXIRqL81IyEsm [email protected]" ]; shell = pkgs.fish; };

security.sudo.wheelNeedsPassword = false; users.mutableUsers = lib.mkForce true; users.defaultUserShell = lib.mkForce pkgs.fish;

system.stateVersion = "25.11"; } ```

1. Create hardware-configuration.nix at hosts/$HOSTNAME/hardware-configuration.nix:

```nix {lib, ...}: { # Hardware configuration for Raspberry Pi $MODEL # Most hardware config is handled by nixos-raspberrypi modules

hardware.enableRedistributableFirmware = true;

# File system configuration for SD card boot # NOTE: Update these labels after imaging if needed fileSystems."/" = { device = "/dev/disk/by-label/NIXOS_SD"; fsType = "ext4"; };

fileSystems."/boot/firmware" = { device = "/dev/disk/by-label/FIRMWARE"; fsType = "vfat"; options = ["noatime"]; };

swapDevices = [];

networking.useDHCP = lib.mkDefault true;

nixpkgs.hostPlatform = "aarch64-linux"; } ```

1. Create user home-configuration.nix at hosts/$HOSTNAME/users/jmeskill/home-configuration.nix:

``nix {flake, ...}: { imports = [ flake.homeModules.default ]; } ``

1. Add to piHosts in flake.nix:

Find the piHosts = { section and add the new host entry. Use the correct modules based on model:

For Pi 5: ``nix $HOSTNAME = inputs.nixos-raspberrypi.lib.nixosSystem { specialArgs = { inherit inputs; flake = inputs.self; nixos-raspberrypi = inputs.nixos-raspberrypi; perSystem = { self = blueprintOutputs.packages.aarch64-linux; }; }; modules = [ inputs.nixos-raspberrypi.nixosModules.raspberry-pi-5.base inputs.nixos-raspberrypi.nixosModules.raspberry-pi-5.display-vc4 inputs.nixos-raspberrypi.nixosModules.sd-image ./hosts/$HOSTNAME/configuration.nix ]; }; ``

For Pi 4: ``nix $HOSTNAME = inputs.nixos-raspberrypi.lib.nixosSystem { specialArgs = { inherit inputs; flake = inputs.self; nixos-raspberrypi = inputs.nixos-raspberrypi; perSystem = { self = blueprintOutputs.packages.aarch64-linux; }; }; modules = [ inputs.nixos-raspberrypi.nixosModules.raspberry-pi-4.base inputs.nixos-raspberrypi.nixosModules.raspberry-pi-4.display-vc4 inputs.nixos-raspberrypi.nixosModules.sd-image ./hosts/$HOSTNAME/configuration.nix ]; }; ``

1. Update hosts/raspberry-pi/README.md - Add the new host to the "Cluster Members" table

1. Verify the configuration builds:

``bash nix eval .#nixosConfigurations.$HOSTNAME.config.system.build.toplevel.outPath ``

1. Output summary:

``` Created new Raspberry Pi host: $HOSTNAME

Files created: - hosts/$HOSTNAME/configuration.nix - hosts/$HOSTNAME/hardware-configuration.nix - hosts/$HOSTNAME/users/jmeskill/home-configuration.nix

Build SD image: nix build .#nixosConfigurations.$HOSTNAME.config.system.build.sdImage \ --builders "ssh://armistice.meskill.farm aarch64-linux" --max-jobs 0

Flash to SD card: zstd -d result/sd-image/*.img.zst -o nixos-$HOSTNAME.img sudo dd if=nixos-$HOSTNAME.img of=/dev/sdX bs=4M status=progress ```

Example Usage

/create-pi-host rpc-5-alpha
/create-pi-host rpc-4-bravo
/create-pi-host rpc-5-charlie