diff --git a/general.nix b/general.nix
index eafc173..61c087a 100644
--- a/general.nix
+++ b/general.nix
@@ -3,38 +3,6 @@ with lib;
 let
   cfg = config.aviallon.general;
   desktopCfg = config.aviallon.desktop;
-  buildUserPubKeyFile = ./nix/id_builder.pub;
-  buildUserKeyFile = ./nix/id_builder;
-
-  getSpeed = cores: threads: cores + (threads - cores) / 2;
-
-  mkBuildMachine = {
-    hostName,
-    cores,
-    systems ? [ "x86_64-linux" ] ,
-    threads ? (cores * 2),
-    features ? [ ],
-    x86ver ? 1 ,
-    ...
-  }@attrs: let
-    speedFactor = getSpeed cores threads;
-  in {
-    inherit hostName speedFactor;
-    systems = systems
-      ++ optional (any (s: s == "x86_64-linux") systems) "i686-linux"
-    ;
-    sshUser = "builder";
-    sshKey = toString buildUserKeyFile;
-    maxJobs = myLib.math.log2 cores;
-    supportedFeatures = [ "kvm" "benchmark" ]
-      ++ optional (speedFactor > 8) "big-parallel"
-      ++ optional (x86ver >= 2) "gccarch-x86-64-v2"
-      ++ optional (x86ver >= 3) "gccarch-x86-64-v3"
-      ++ optional (x86ver >= 4) "gccarch-x86-64-v4"
-      ++ features
-    ;
-    
-  };
 in
 {
   imports = [
@@ -117,39 +85,6 @@ in
     };
 
     environment.noXlibs = mkIf (cfg.minimal && (!desktopCfg.enable)) true;
-
-    nix.buildMachines = []
-      # luke-skywalker-nixos
-      ++ optional (config.networking.hostName != "luke-skywalker-nixos") (mkBuildMachine {
-        hostName = "2a01:e0a:18e:8670:ae71:8e51:19af:91a4";
-        cores = 16;
-        threads = 32;
-        x86ver = 3;
-      })
-      ++ optional false (mkBuildMachine {
-        hostName = "cachan.lesviallon.fr";
-        cores = 6;
-        threads = 6;
-      })
-    ;
-
-    programs.ssh.extraConfig = ''
-      Host cachan.lesviallon.fr
-        Port 52222
-    '';
-    
-    users.users.builder = {
-      isSystemUser = true;
-      group = "builder";
-      hashedPassword = mkForce null; # Must not have a password!
-      openssh.authorizedKeys.keys = [
-        (readFile buildUserPubKeyFile)
-      ];
-      shell = pkgs.bashInteractive;
-    };
-    users.groups.builder = {};
-    nix.settings.trusted-users = [ "builder" ];
-    nix.distributedBuilds = mkDefault true;
   };
 
 }
diff --git a/nix/builder.nix b/nix/builder.nix
new file mode 100644
index 0000000..935ff5a
--- /dev/null
+++ b/nix/builder.nix
@@ -0,0 +1,172 @@
+{ config, pkgs, lib, myLib, ... }:
+with lib;
+let
+  cfg = config.aviallon.nix;
+  generalCfg = config.aviallon.general;
+  desktopCfg = config.aviallon.desktop;
+  buildUserPubKeyFile = ./id_builder.pub;
+  buildUserKeyFile = ./id_builder;
+  buildUserKeyFilePath = "/var/lib/nixos/aviallon.id_builder";
+
+  getSpeed = cores: threads: cores + (threads - cores) / 2;
+
+  mkBuildMachine = {
+    hostName,
+    cores,
+    systems ? [ "x86_64-linux" ] ,
+    threads ? (cores * 2),
+    features ? [ ],
+    x86ver ? 1 ,
+    ...
+  }@attrs: let
+    speedFactor = getSpeed cores threads;
+  in {
+    inherit hostName speedFactor;
+    systems = systems
+      ++ optional (any (s: s == "x86_64-linux") systems) "i686-linux"
+    ;
+    sshUser = "builder";
+    sshKey = buildUserKeyFilePath;
+    maxJobs = myLib.math.log2 cores;
+    supportedFeatures = [ "kvm" "benchmark" ]
+      ++ optional (speedFactor > 8) "big-parallel"
+      ++ optional (x86ver >= 2) "gccarch-x86-64-v2"
+      ++ optional (x86ver >= 3) "gccarch-x86-64-v3"
+      ++ optional (x86ver >= 4) "gccarch-x86-64-v4"
+      ++ features
+    ;
+    
+  };
+
+  machineList = filterAttrs (name: value: config.networking.hostName != name && value.enable) cfg.builder.buildMachines;
+in
+{
+  imports = [
+    #(mkRenamedOptionModule [ "aviallon" "general" "flakes" "enable" ] [ "" ] "Flakes are now enabled by default")
+  ];
+
+  options.aviallon.nix.builder = {
+    
+    buildMachines = mkOption {
+      type = types.attrsOf (types.submoduleWith {
+        modules = [
+        ({ config, options, name, ...}:
+        {
+          options = {
+            enable = mkOption {
+              type = types.bool;
+              default = true;
+              description = "Wether to enable or to disable this builder";
+              example = false;
+            };
+            hostName = mkOption {
+              type = types.str;
+              example = "luke-skywalker-nixos";
+              description = lib.mdDoc ''
+                Builder's host name
+              '';
+            };
+            sshConfig = mkOption {
+              type = types.str;
+              default = "";
+              example = ''
+                ProxyJump example.com
+                Port 2222
+              '';
+              description = "Extra ssh config for the builder.";
+            };
+            cores = mkOption {
+              type = with types; ints.unsigned;
+              example = 8;
+              description = "How many physical cores the builder has.";
+            };
+            threads = mkOption {
+              type = with types; addCheck ints.unsigned (n: n >= config.cores);
+              example = 16;
+              description = lib.mdDoc "How many physical _threads_ the builder has.";
+            };
+            x86ver = mkOption {
+              default = 1;
+              type = with types; addCheck ints.positive (n: n >= 1 && n <= 4);
+              example = 3;
+              description = "Maximum x86-64 feature level supported.";
+            };
+          };
+
+        })]; });
+      default = {};
+      example = literalExpression
+        ''
+          {
+            luke-skywalker-nixos = {
+              hostName = "2aXX:e0a:18e:8670::";
+              cores = 16;
+              threads = 32;
+              x86ver = 3;
+            };
+          }
+        '';
+      description = "NixOS builders";
+    };
+  };
+
+  config = {
+    nix.buildMachines = traceValSeqN 3 (mapAttrsToList (name: value:
+      mkBuildMachine {
+        inherit (value) hostName cores threads x86ver;
+      }
+    ) machineList);
+
+    programs.ssh.extraConfig = concatStringsSep "\n" (mapAttrsToList (name: value:
+      (optionalString (value.sshConfig != "")
+        ''
+        Host ${value.hostName}
+          ${value.sshConfig}
+        ''
+      )
+    ) machineList);
+
+    aviallon.nix.builder.buildMachines = {
+      luke-skywalker-nixos = mkDefault {
+        hostName = "2a01:e0a:18e:8670:ae71:8e51:19af:91a4";
+        cores = 16;
+        threads = 32;
+        x86ver = 3;
+      };
+      elrond = mkDefault {
+        enable = false;
+        hostName = "cachan.lesviallon.fr";
+        sshConfig = ''
+          Port 52222
+        '';
+        cores = 6;
+        threads = 6;
+        x86ver = 2;
+      };
+    };
+
+    users.users.builder = {
+      isSystemUser = true;
+      group = "builder";
+      password = mkForce null; # Must not have a password!
+      openssh.authorizedKeys.keys = [
+        (readFile buildUserPubKeyFile)
+      ];
+      shell = pkgs.bashInteractive;
+    };
+    users.groups.builder = {};
+    nix.settings.trusted-users = [ "builder" ];
+
+    boot.enableContainers = mkForce true;
+
+    nix.distributedBuilds = mkDefault true;
+
+    system.activationScripts = {
+      buildUserKeySetup.text = ''
+        cp --force -v ${buildUserKeyFile} ${buildUserKeyFilePath}
+        chmod -v 400 ${buildUserKeyFilePath}
+      '';
+    };
+  };
+
+}
diff --git a/nix/default.nix b/nix/default.nix
index ce62f56..12e2d9e 100644
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -2,5 +2,6 @@
 {
   imports = [
     ./nix.nix
+    ./builder.nix
   ];
 }