flake: add mediaserver-vm host for testing services from scratch

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

HEAD

@@ -0,0 +1 @@
+Subproject commit 11f73e9e6aa6ac3343750590e00b53a6dd70fe2e

flake.nix

@@ -39,7 +39,6 @@
         specialArgs = { inherit inputs; };
         modules = [
           ./hosts/${hostname}.nix
-          ./hosts/hardware/${hostname}.nix
           ./common.nix
           home-manager.nixosModules.home-manager
           stylix.nixosModules.stylix
@@ -49,9 +48,14 @@
     in
     {
       nixosConfigurations = {
-        FredOS-Gaming      = mkHost "FredOS-Gaming"      [];
+        FredOS-Gaming      = mkHost "FredOS-Gaming"      [ ./hosts/hardware/FredOS-Gaming.nix ];
-        FredOS-Mediaserver = mkHost "FredOS-Mediaserver"  [];
+        FredOS-Mediaserver = mkHost "FredOS-Mediaserver" [ ./hosts/hardware/FredOS-Mediaserver.nix ];
-        FredOS-Macbook     = mkHost "FredOS-Macbook"      [];
+        FredOS-Macbook     = mkHost "FredOS-Macbook"     [ ./hosts/hardware/FredOS-Macbook.nix ];
+
+        # Mediaserver's services on fake hardware, for testing from-scratch
+        # bring-up (arr-interconnect especially) in a throwaway VM:
+        #   nixos-rebuild build-vm --flake .#mediaserver-vm
+        mediaserver-vm     = mkHost "FredOS-Mediaserver" [ ./hosts/hardware/vm.nix ];
       };
     };
 }

hosts/hardware/vm.nix

@@ -0,0 +1,48 @@
+#./hosts/hardware/vm.nix
+# Stand-in "hardware" for `nixos-rebuild build-vm --flake .#mediaserver-vm`.
+#
+# Keeps hostName = FredOS-Mediaserver so every hostname-gated module under
+# services/ switches on, but throws away the real disks, NICs and GPU. The
+# point is watching arr-interconnect wire a *fresh* stack from empty state —
+# something the live host can't demonstrate anymore, since its /var/lib is
+# already populated and the script is a reconciler, not an installer.
+{ lib, ... }:
+{
+  networking.hostName = "FredOS-Mediaserver";
+  system.stateVersion = "25.11";
+  nixpkgs.hostPlatform = "x86_64-linux";
+
+  # qemu-vm.nix supplies "/" and the bootloader. Only the media pool has to
+  # exist by hand, so the *arr root folders resolve — contents are throwaway.
+  fileSystems."/mnt/storage" = {
+    device = "tmpfs";
+    fsType = "tmpfs";
+    options = [ "mode=0777" ];
+  };
+
+  # --- Undo router.nix. This VM is not a router. ---
+  # Its networkd units match NIC names pinned to the real MACs, so the VM's
+  # NIC matches nothing and comes up unconfigured; its nft input chain is
+  # policy-drop, which would eat the forwarded ports below. Scripted DHCP on
+  # QEMU's user-mode NIC replaces both.
+  networking.useNetworkd = lib.mkForce false;
+  networking.nftables.tables = lib.mkForce { };
+  services.dnsmasq.enable = lib.mkForce false;
+
+  virtualisation.vmVariant.virtualisation = {
+    memorySize = 8192;
+    cores = 4;
+    diskSize = 32768;   # docker images for shelfarr/profilarr are not small
+    graphics = false;   # serial console; ctrl-a x to quit
+    forwardPorts = [
+      { from = "host"; host.port = 2222; guest.port = 22; }
+      { from = "host"; host.port = 8989; guest.port = 8989; }  # sonarr
+      { from = "host"; host.port = 7878; guest.port = 7878; }  # radarr
+      { from = "host"; host.port = 9696; guest.port = 9696; }  # prowlarr
+      { from = "host"; host.port = 6767; guest.port = 6767; }  # bazarr
+      { from = "host"; host.port = 8080; guest.port = 8080; }  # qbittorrent
+      { from = "host"; host.port = 8096; guest.port = 8096; }  # jellyfin
+      { from = "host"; host.port = 5055; guest.port = 5055; }  # seerr
+    ];
+  };
+}