rp3: rebuild from scratch and update the installation instructions

README.md

@@ -175,43 +175,59 @@ router/setup.sh
 
 ## Raspberry Pi 3 Model B
 
-### Raspbian
+### NixOS
+
+The installation instructions are based those from
+[nix.dev](https://nix.dev/tutorials/nixos/installing-nixos-on-a-raspberry-pi.html).
 
-Setup SD card:
+Download the latest aarch64 SD card image from
+[Hydra](https://hydra.nixos.org/search?query=sd_image) and flash it on an SD
+card:
 
 ```
-wget https://downloads.raspberrypi.org/raspbian_lite_latest
-unzip -p raspbian_lite_latest | sudo dd of=/dev/mmcblk0 bs=4M conv=fsync status=progress
-# remove then reinsert SD card
-pmount /dev/mmcblk0p1
-touch /media/mmcblk0p1/ssh
-pumount /dev/mmcblk0p1
+wget https://hydra.nixos.org/build/226381178/download/1/nixos-sd-image-23.11pre500597.0fbe93c5a7c-aarch64-linux.img.zst
+unzstd nixos-sd-image-23.11pre500597.0fbe93c5a7c-aarch64-linux.img
+sudo dd \
+  if=nixos-sd-image-23.11pre500597.0fbe93c5a7c-aarch64-linux.img \
+  of=/dev/mmcblk0 bs=4096 conv=fsync status=progress
 ```
 
-### NixOS
-
-The official NixOS images boot without any problems.  Download the latest
-aarch64 SD card image from
-[Hydra](https://hydra.nixos.org/search?query=sd_image).
-
-Flash the image to an SD card as described in the [previous section](#raspbian).
-
-Boot the system then start an SSH server and set a temporary password for the
-root user:
+Insert the SD card in the Raspberry Pi and power it up.  The installer runs
+already an SSH server. Set a temporary password for the root user:
 
 ```
-systemctl start sshd
 passwd root
 ```
 
 The password is only used for the first time access.  Password authentication
 will be disabled later.  Connect to the freshly booted system using SSH.
 
-If you want to manage Pi using NixOps, there's some extra steps required.
+Folow [these instructions][NixOSBootWifi] to connect to a Wifi network.  When
+connected the system will have the hostname `nixos`.
+
+Using the password authentication, deploy your SSH public keys:
+
+```
+ssh-copy-id root@nixos
+```
+
+On the Raspberry Pi, store the WIFI SSID and password in the file
+`/etc/secrets/wireless.env` with the following format:
+
+```
+WIFI_SSID=...
+WIFI_KEY=...
+```
 
-NixOps compiles all managed systems on the control PC where it runs. Then, it
-copies the binaries to the target systems.  This works well for i686 and amd64
-architectures but it doesn't work for aarch64.
+Finally, build the system with the custom configuration:
+
+```
+nixos-rebuild switch
+    --flake ".#rp3" \
+    --target-host "root@nixos" \
+    --build-host "root@nixos" \
+    --fast
+```
 
 I tried to setup cross-compilation to aarch64, but it didn't work.
 
@@ -298,3 +314,5 @@ dashboard configuration in this repository:
 ```
 nix run .#mqtt-dash-listen > nodemcu/mqtt-dash.json
 ```
+
+[NixOSBootWifi]: https://nixos.org/manual/nixos/stable/#sec-installation-booting-networking

hardware/rp3.nix

@@ -10,29 +10,27 @@ in
   nixpkgs.system = "aarch64-linux";
 
   boot = {
-    initrd = {
-      availableKernelModules = [
-        "bcm2835_dma"
-        "i2c_bcm2835"
-        "usbhid"
-        "vc4"
-      ];
-      kernelModules = [ ];
+    initrd.kernelModules = [ "vc4" "bcm2835_dma" "i2c_bcm2835" ];
+    loader = {
+      grub.enable = false;
+
+      raspberryPi = {
+        enable = true;
+        uboot.enable = true;
+        version = 3;
+      };
     };
+  };
 
-    kernelParams = [ "cma=32M" ];
-
-    extraModulePackages = [ ];
-
-    loader.grub.enable = false;
-
-    loader.raspberryPi = {
-      enable = true;
-      uboot.enable = true;
-      version = 3;
-    };
+  networking.wireless = {
+    enable = true;
+    environmentFile = "/etc/secrets/wireless.env";
+    networks."@WIFI_SSID@".psk = "@WIFI_KEY@";
+    interfaces = [ "wlan0" ];
   };
 
+  hardware.enableRedistributableFirmware = true;
+
   environment.systemPackages = with pkgs; [
     libraspberrypi
   ];

host-rp3.nix

@@ -5,7 +5,8 @@
     ./hardware/rp3.nix
     ./modules/common.nix
     ./modules/remote-builder
+    ./modules/consul/client.nix
   ];
 
-  system.stateVersion = "22.05";
+  system.stateVersion = "23.11";
 }

modules/buildMachines.nix

@@ -9,7 +9,7 @@
 
     rp3 = {
       hostNames = [ "rp3" "rp3.thewagner.home" ];
-      publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILK0illQrUbCmn+UHgM79tDecSItLUVNuWi/Sg+DW2tr";
+      publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJgVezT5bpUOihQmNEV6XC/RsUtFDcd9vcLZ7cUKPp83";
     };
 
     rp4 = {