Start reworking the server for nix flakes

This removes all existing services as well, in preparation of moving
them to `podman`. These are easier to update to
virtualisation.oci-containers while retaining the "networks" through
pods.

configuration/default.nix

@@ -0,0 +1,57 @@
+{ config, pkgs, ... }:
+
+{
+  imports = [ ];
+
+  nix = {
+    package = pkgs.nixFlakes;
+    extraOptions = ''
+      experimental-features = nix-command flakes
+    '';
+  };
+
+  networking = {
+    hostName = "tlaternet";
+
+    usePredictableInterfaceNames = false;
+    useDHCP = false;
+    interfaces.eth0.useDHCP = true;
+
+    firewall.allowedTCPPorts = [ 80 443 2222 2221 25565 ];
+  };
+
+  time.timeZone = "Europe/London";
+
+  users.users.tlater = {
+    isNormalUser = true;
+    extraGroups = [ "wheel" ];
+    openssh.authorizedKeys.keyFiles = [ ../keys/tlater.pub ];
+  };
+
+  services.openssh = {
+    enable = true;
+    allowSFTP = false;
+    passwordAuthentication = false;
+    permitRootLogin = "no";
+    ports = [ 2222 ];
+    startWhenNeeded = true;
+  };
+
+  services.nginx = {
+    enable = true;
+    recommendedTlsSettings = true;
+    recommendedOptimisation = true;
+    recommendedGzipSettings = true;
+    recommendedProxySettings = true;
+    clientMaxBodySize = "10G";
+  };
+
+  security.acme = {
+    email = "tm@tlater.net";
+    acceptTerms = true;
+  };
+
+  virtualisation.oci-containers.backend = "podman";
+
+  system.stateVersion = "20.09";
+}

configuration/hardware-configuration.nix

@@ -0,0 +1,31 @@
+# Do not modify this file!  It was generated by ‘nixos-generate-config’
+# and may be overwritten by future invocations.  Please make changes
+# to /etc/nixos/configuration.nix instead.
+{ config, lib, pkgs, ... }:
+
+{
+  imports =
+    [ <nixpkgs/nixos/modules/profiles/qemu-guest.nix>
+    ];
+
+  boot.initrd.availableKernelModules = [ "virtio_pci" "ahci" "sd_mod" ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ ];
+  boot.extraModulePackages = [ ];
+
+  fileSystems."/" =
+    { device = "/dev/disk/by-uuid/e541bdc3-79d6-459f-9169-92b13b0a8959";
+      fsType = "ext4";
+    };
+
+  fileSystems."/var" =
+    { device = "/dev/disk/by-uuid/79f8fbbd-476d-4e1a-9675-a8474d98f42f";
+      fsType = "ext4";
+    };
+
+  swapDevices =
+    [ { device = "/dev/disk/by-uuid/45c8ad29-3861-4e68-a566-47e6d9269dca"; }
+    ];
+
+  nix.maxJobs = lib.mkDefault 2;
+}

configuration/linode.nix

@@ -0,0 +1,20 @@
+{ config, lib, pkgs, ... }:
+
+{
+  # Required for the lish console
+  boot.kernelParams = [ "console=ttyS0,19200n8" ];
+
+  boot.loader = {
+    # Timeout to allow lish to connect
+    timeout = 10;
+
+    grub = {
+      device = "nodev";
+      extraConfig = ''
+        serial --speed=19200 --unit=0 --word=8 --parity=no --stop=1;
+        terminal_input serial;
+        terminal_output serial;
+      '';
+    };
+  };
+}