1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
# darwin.linux-builder {#sec-darwin-builder}
`darwin.linux-builder` provides a way to bootstrap a Linux builder on a macOS machine.
This requires macOS version 12.4 or later.
The builder runs on host port 31022 by default.
You can change it by overriding `virtualisation.darwin-builder.hostPort`.
See the [example](#sec-darwin-builder-example-flake).
You will also need to be a trusted user for your Nix installation. In other
words, your `/etc/nix/nix.conf` should have something like:
```
extra-trusted-users = <your username goes here>
```
To launch the builder, run the following flake:
```ShellSession
$ nix run nixpkgs#darwin.linux-builder
```
That will prompt you to enter your `sudo` password:
```
+ sudo --reset-timestamp /nix/store/…-install-credentials.sh ./keys
Password:
```
… so that it can install a private key used to `ssh` into the build server.
After that the script will launch the virtual machine and automatically log you
in as the `builder` user:
```
<<< Welcome to NixOS 22.11.20220901.1bd8d11 (aarch64) - ttyAMA0 >>>
Run 'nixos-help' for the NixOS manual.
nixos login: builder (automatic login)
[builder@nixos:~]$
```
> Note: When you need to stop the VM, run `shutdown now` as the `builder` user.
To delegate builds to the remote builder, add the following options to your
`nix.conf` file:
```
# - Replace ${ARCH} with either aarch64 or x86_64 to match your host machine
# - Replace ${MAX_JOBS} with the maximum number of builds (pick 4 if you're not sure)
builders = ssh-ng://builder@linux-builder ${ARCH}-linux /etc/nix/builder_ed25519 ${MAX_JOBS} - - - c3NoLWVkMjU1MTkgQUFBQUMzTnphQzFsWkRJMU5URTVBQUFBSUpCV2N4Yi9CbGFxdDFhdU90RStGOFFVV3JVb3RpQzVxQkorVXVFV2RWQ2Igcm9vdEBuaXhvcwo=
# Not strictly necessary, but this will reduce your disk utilization
builders-use-substitutes = true
```
To allow Nix to connect to a builder not running on port 22, you will also need to create a new file at `/etc/ssh/ssh_config.d/100-linux-builder.conf`:
```
Host linux-builder
Hostname localhost
HostKeyAlias linux-builder
Port 31022
```
… and then restart your Nix daemon to apply the change:
```ShellSession
$ sudo launchctl kickstart -k system/org.nixos.nix-daemon
```
## Example flake usage {#sec-darwin-builder-example-flake}
```
{
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 = "${darwin-builder.config.system.build.macos-builder-installer}/bin/create-builder";
serviceConfig = {
KeepAlive = true;
RunAtLoad = true;
StandardOutPath = "/var/log/darwin-builder.log";
StandardErrorPath = "/var/log/darwin-builder.log";
};
};
}
];
};
};
};
}
```
## Reconfiguring the builder {#sec-darwin-builder-reconfiguring}
Initially you should not change the builder configuration else you will not be
able to use the binary cache. However, after you have the builder running locally
you may use it to build a modified builder with additional storage or memory.
To do this, you just need to set the `virtualisation.darwin-builder.*` parameters as
in the example below and rebuild.
```
darwin-builder = nixpkgs.lib.nixosSystem {
system = linuxSystem;
modules = [
"${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.
|