fix distributed setup local

flake.lock

@@ -487,11 +487,11 @@
     },
     "nix-secrets": {
       "locked": {
-        "lastModified": 1736337009,
-        "narHash": "sha256-5seeOYCOJrvhbKIj64bAzeSJN80hdVp08ufArlBf+qg=",
+        "lastModified": 1736339437,
+        "narHash": "sha256-Em8E6Ml2whMU1IoEB3OI3eKhjSu2J/xbXdlIt+8x61U=",
         "ref": "refs/heads/master",
-        "rev": "bd63772717581b787f1f2aaac3fb909eaae2c2b7",
-        "revCount": 193,
+        "rev": "7c6042a975808186934e012ad32ae0e03ab60bff",
+        "revCount": 194,
         "type": "git",
         "url": "ssh://git@git.bitlab21.com/sam/nix-secrets.git"
       },

hosts/common/optional/distributed_builds/local-machine.nix

@@ -1,4 +1,33 @@
+{ pkgs, configVars, ... }:
+let
+  remoteMachineIp = configVars.networking.addresses.remote-builder.ip;
+in
 {
+  nix.distributedBuilds = true;
+  nix.settings.builders-use-substitutes = true;
+  nix.settings.max-jobs = 0;
+  nix.settings.trusted-substituters = ["ssh://${remoteMachineIp}"];
+  nix.settings.substituters = ["ssh://${remoteMachineIp}"];
+
+  nix.buildMachines = [
+    {
+      hostName = remoteMachineIp;
+      sshUser = "remotebuild";
+      speedFactor = 1;
+      maxJobs = 10;
+      sshKey = "/root/.ssh/remotebuild";
+      system = pkgs.stdenv.hostPlatform.system;
+      supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
+    }
+  ];
+
+  # TODO: set known host here when have static ip on main server
+  # programs.ssh.knownHosts = {
+  #   "merlin" = {
+  #     publicKey = "server pubkey";
+  #   };
+  # };
+
   sops.secrets = {
     "ssh_keys/root/remotebuild" = {
       path = "/root/.ssh/remotebuild";

hosts/semita/default.nix

@@ -59,6 +59,8 @@ in {
 
     ../common/optional/restic-backup.nix
     ../common/optional/nixos-containers/backup-server.nix
+
+    ../common/optional/distributed_builds/local-machine.nix
   ];
 
   fileSystems."/media/main-ssd" = {