populate ip address based on hostname and populate the hostfile with other vm ips

nixos/roles/vmNetwork.nix

@@ -6,7 +6,9 @@
   inherit (lib) lists mapAttrsToList;
   inherit (lib.attrsets) foldAttrs concatMapAttrs;
   inherit (lib.asserts) assertMsg;
-  inherit (builtins) elem;
+  inherit (lib.lists) filter last init;
+  inherit (lib.strings) splitString toInt concatStringsSep;
+  inherit (builtins) elem toString;
   hostmap = import ./hostmap.nix;
   myhostName = config.networking.hostName;
   # To turn the hostmap around suitable for networking.hosts the following simple code almost works
@@ -19,14 +21,26 @@
     if (elem myhostName hosts)
     # nixos maps the hostname to the loopback 127.0.0.2 by default, so we exclude it here.
     # there is also a default localhost to 127.0.0.1 in place
-    then {"127.0.0.1" = lists.filter (x: x != myhostName) hosts;}
+    then {"127.0.0.1" = filter (x: x != myhostName) hosts;}
     else {${ip} = hosts;})
   globalhosts;
   myIp = assert (assertMsg (hostmap ? ${myhostName}.ipv4) "${myhostName} has no ip configured in nixos/roles/hostmap.nix"); hostmap.${myhostName}.ipv4;
 in {
-  imports = [
-    ../modules/vmNetwork.nix
-  ];
-  networking.hosts = myhosts;
-  vmNetwork.ipv4 = myIp;
+  networking = {
+    hosts = myhosts;
+    interfaces.enX0.ipv4.addresses = [
+      {
+        address = myIp;
+        prefixLength = 16;
+      }
+    ];
+    defaultGateway = let
+      addr = splitString "." myIp;
+      addrInit = init addr;
+      addrLastInt = toString (toInt (last addr) + 127);
+    in
+      concatStringsSep "." (addrInit ++ [addrLastInt]);
+    # https://www.hrz.tu-darmstadt.de/services/it_services/nameserver_dns/index.de.jsp
+    nameservers = ["130.83.22.63" "130.83.22.60" "130.83.56.60"];
+  };
 }