start set up for multi-location nixos flake

nixos/hosts/olympus/wireguard/configuration.nix

@@ -0,0 +1,62 @@
+# Edit this configuration file to define what should be installed on
+# your system.  Help is available in the configuration.nix(5) man page
+# and in the NixOS manual (accessible by running ‘nixos-help’).
+
+{ lib, config, pkgs, inputs, ... }:
+let vs = config.vault-secrets.secrets; in
+{
+  imports = [ ];
+
+  networking.hostName = "wireguard";
+
+  # This value determines the NixOS release from which the default
+  # settings for stateful data, like file locations and database versions
+  # on your system were taken. It‘s perfectly fine and recommended to leave
+  # this value at the release version of the first install of this system.
+  # Before changing this value read the documentation for this option
+  # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
+  system.stateVersion = "21.11"; # Did you read the comment?
+
+  # Additional packages
+  environment.systemPackages = with pkgs; [ wireguard-tools ];
+
+  environment.noXlibs = lib.mkForce false;
+
+  networking.firewall.allowedUDPPorts = [
+    config.networking.wireguard.interfaces.wg0.listenPort
+  ];
+
+  vault-secrets.secrets.wireguard = {
+    services = [ "wireguard-wg0" ];
+  };
+
+  networking.nat = {
+    enable = true;
+    internalInterfaces = [ "wg0" ];
+    externalInterface = "eth0";
+  };
+
+  services.prometheus.exporters.wireguard = {
+    enable = true;
+    openFirewall = true;
+  };
+
+  networking.wireguard.interfaces.wg0 = {
+    ips = [ "10.100.0.1/24" ];
+    listenPort = 51820;
+    privateKeyFile = "${vs.wireguard}/privateKey";
+
+    peers = [
+      {
+        # Phone
+        publicKey = "K+99mvSYs4urcclreQDLA1pekD4xtu/mpS2uVWw8Bws=";
+        allowedIPs = [ "10.100.0.2/32" ];
+      }
+      {
+        # Laura's laptop
+        publicKey = "ZWIaDGrASlTkEK75j10VeGCvrIGfpk4GPobmqcYX2D0=";
+        allowedIPs = [ "10.100.0.3/32" ];
+      }
+    ];
+  };
+}