setup octodns for automatic dns records

hosts/freun-dev/configuration.nix

@@ -3,7 +3,10 @@
 # and in the NixOS manual (accessible by running `nixos-help`).
 
 { config, pkgs, ssh, ... }:
-
+let
+  ipv4Address = "65.21.145.150";
+  ipv6Address = "2a01:4f9:c011:9ac1::1";
+in
 {
   nix = {
     settings = {
@@ -25,13 +28,24 @@
   networking.useDHCP = false;
   networking.nftables.enable = true;
 
+  services.octodns.records."" = {
+    A = {
+      ttl = 86400;
+      values = [ ipv4Address ];
+    };
+    AAAA = {
+      ttl = 86400;
+      values = [ ipv6Address ];
+    };
+  };
+
   systemd.network = {
     enable = true;
     networks.static = {
       name = "enp1s0";
       address = [
-        "65.21.145.150/32"
-        "2a01:4f9:c011:9ac1::1/64"
+        "${ipv4Address}/32"
+        "${ipv6Address}/64"
       ];
       routes = [
         { Gateway = "fe80::1"; }

hosts/freun-dev/secrets.nix

@@ -11,6 +11,7 @@
         "vaultwarden"
         "donetick"
         "dnote"
+        "octodns"
       ]
     ) // {
     smtp-password = {

hosts/freun-dev/services.nix

@@ -12,7 +12,6 @@ let
   secrets = config.age.secrets;
 in
 {
-  services.postgresql.package = pkgs.postgresql_16;
   virtualisation.podman.enable = true;
   virtualisation.oci-containers.backend = "podman";
 
@@ -33,6 +32,16 @@ in
   };
 
   services = {
+    postgresql.package = pkgs.postgresql_16;
+    octodns = {
+      enable = true;
+      records."".MX = {
+        ttl = 86400;
+        values = [{ exchange = "${smtp.host}."; }];
+      };
+      defaults.CNAME.ttl = 60;
+    };
+
     hastebin = {
       enable = true;
       subdomain = "bin";