nixos/darwin-builder: add disk space options (#224480)

1 files changed, 86 insertions, 0 deletions

diff --git a/doc/builders/special/darwin-builder.section.md b/doc/builders/special/darwin-builder.section.md
index 3913b692498d..30bf2d095102 100644
--- a/doc/builders/special/darwin-builder.section.md
+++ b/doc/builders/special/darwin-builder.section.md
@@ -61,3 +61,89 @@ builders-use-substitutes = true
 ```ShellSession
 $ sudo launchctl kickstart -k system/org.nixos.nix-daemon
 ```
+
+## Example flake usage
+
+```
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-22.11-darwin";
+    darwin.url = "github:lnl7/nix-darwin/master";
+    darwin.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { self, darwin, nixpkgs, ... }@inputs:
+  let
+
+    inherit (darwin.lib) darwinSystem;
+    system = "aarch64-darwin";
+    pkgs = nixpkgs.legacyPackages."${system}";
+    linuxSystem = builtins.replaceStrings [ "darwin" ] [ "linux" ] system;
+
+    darwin-builder = nixpkgs.lib.nixosSystem {
+      system = linuxSystem;
+      modules = [
+        "${nixpkgs}/nixos/modules/profiles/macos-builder.nix"
+        { virtualisation.host.pkgs = pkgs; }
+      ];
+    };
+  in {
+
+    darwinConfigurations = {
+      machine1 = darwinSystem {
+        inherit system;
+        modules = [
+          {
+            nix.distributedBuilds = true;
+            nix.buildMachines = [{
+              hostName = "ssh://builder@localhost";
+              system = linuxSystem;
+              maxJobs = 4;
+              supportedFeatures = [ "kvm" "benchmark" "big-parallel" ];
+            }];
+
+            launchd.daemons.darwin-builder = {
+              command = "${darwin-builder.config.system.build.macos-builder-installer}/bin/create-builder";
+              serviceConfig = {
+                KeepAlive = true;
+                RunAtLoad = true;
+                StandardOutPath = "/var/log/darwin-builder.log";
+                StandardErrorPath = "/var/log/darwin-builder.log";
+              };
+            };
+          }
+        ];
+      };
+    };
+
+  };
+}
+```
+
+## Reconfiguring the builder
+
+Initially you should not change the builder configuration else you will not be
+able to use the binary cache. However, after you have the builder running locally
+you may use it to build a modified builder with additional storage or memory.
+
+To do this, you just need to set the `virtualisation.darwin-builder.*` parameters as
+in the example below and rebuild.
+
+```
+    darwin-builder = nixpkgs.lib.nixosSystem {
+      system = linuxSystem;
+      modules = [
+        "${nixpkgs}/nixos/modules/profiles/macos-builder.nix"
+        {
+          virtualisation.host.pkgs = pkgs;
+          virtualisation.darwin-builder.diskSize = 5120;
+          virtualisation.darwin-builder.memorySize = 1024;
+          virtualisation.darwin-builder.hostPort = 33022;
+          virtualisation.darwin-builder.workingDirectory = "/var/lib/darwin-builder";
+        }
+      ];
+```
+
+You may make any other changes to your VM in this attribute set. For example,
+you could enable Docker or X11 forwarding to your Darwin host.
+