feat: add unified microvm & container definition; add net, misc, disko lib extension

modules/guests/microvm.nix

@@ -0,0 +1,82 @@
+guestName: guestCfg: {
+  config,
+  inputs,
+  lib,
+  pkgs,
+  ...
+}: let
+  inherit
+    (lib)
+    flip
+    mapAttrsToList
+    mkDefault
+    mkForce
+    ;
+in {
+  specialArgs = guestCfg.extraSpecialArgs;
+  pkgs = inputs.self.pkgs.${guestCfg.microvm.system};
+  inherit (guestCfg) autostart;
+  config = {
+    imports =
+      guestCfg.modules
+      ++ [
+        (import ./common-guest-config.nix guestName guestCfg)
+        ({config, ...}: {
+          # Set early hostname too, so we can associate those logs to this host and don't get "localhost" entries in loki
+          boot.kernelParams = ["systemd.hostname=${config.networking.hostName}"];
+        })
+      ];
+
+    # TODO needed because of https://github.com/NixOS/nixpkgs/issues/102137
+    environment.noXlibs = mkForce false;
+    lib.microvm.mac = guestCfg.microvm.mac;
+
+    microvm = {
+      hypervisor = mkDefault "qemu";
+
+      # Give them some juice by default
+      mem = mkDefault (1024 + 2048);
+
+      # Add a writable store overlay, but since this is always ephemeral
+      # disable any store optimization from nix.
+      writableStoreOverlay = "/nix/.rw-store";
+
+      # MACVTAP bridge to the host's network
+      interfaces = [
+        {
+          type = "macvtap";
+          id = "vm-${guestName}";
+          inherit (guestCfg.microvm) mac;
+          macvtap = {
+            link = guestCfg.microvm.macvtap;
+            mode = "bridge";
+          };
+        }
+      ];
+
+      shares =
+        [
+          # Share the nix-store of the host
+          {
+            source = "/nix/store";
+            mountPoint = "/nix/.ro-store";
+            tag = "ro-store";
+            proto = "virtiofs";
+          }
+        ]
+        ++ flip mapAttrsToList guestCfg.zfs (
+          _: zfsCfg: {
+            source = zfsCfg.hostMountpoint;
+            mountPoint = zfsCfg.guestMountpoint;
+            tag = builtins.substring 0 16 (builtins.hashString "sha256" zfsCfg.hostMountpoint);
+            proto = "virtiofs";
+          }
+        );
+    };
+
+    networking.renameInterfacesByMac.${guestCfg.networking.mainLinkName} = guestCfg.microvm.mac;
+    systemd.network.networks."10-${guestCfg.networking.mainLinkName}".matchConfig = mkForce {
+      MACAddress = guestCfg.microvm.mac;
+    };
+  };
+}