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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
|
{ config, pkgs, ... }:
with pkgs.lib;
let
cfg = config.nix;
inherit (config.environment) nix;
makeNixBuildUser = nr:
{ name = "nixbld${toString nr}";
description = "Nix build user ${toString nr}";
/* For consistency with the setgid(2), setuid(2), and setgroups(2)
calls in `libstore/build.cc', don't add any supplementary group
here except "nixbld". */
uid = builtins.add config.ids.uids.nixbld nr;
group = "nixbld";
extraGroups = [ "nixbld" ];
};
in
{
###### interface
options = {
environment.nix = mkOption {
default = pkgs.nixUnstable;
merge = mergeOneOption;
description = ''
This option specifies the Nix package instance to use throughout the system.
'';
};
nix = {
maxJobs = mkOption {
default = 1;
example = 2;
description = "
This option defines the maximum number of jobs that Nix will try
to build in parallel. The default is 1. You should generally
set it to the number of CPUs in your system (e.g., 2 on a Athlon
64 X2).
";
};
useChroot = mkOption {
default = false;
example = true;
description = "
If set, Nix will perform builds in a chroot-environment that it
will set up automatically for each build. This prevents
impurities in builds by disallowing access to dependencies
outside of the Nix store.
";
};
chrootDirs = mkOption {
default = [];
example = [ "/dev" "/proc" ];
description =
''
Directories from the host filesystem to be included
in the chroot.
'';
};
extraOptions = mkOption {
default = "";
example = "
gc-keep-outputs = true
gc-keep-derivations = true
";
description = "Additional text appended to <filename>nix.conf<filename>.";
};
distributedBuilds = mkOption {
default = false;
description = "
Whether to distribute builds to the machines listed in
<option>nix.buildMachines</option>.
If you know that the <option>buildMachines</option> are not
always available either use nixos
<command>nixos-rebuild --no-build-hook</command>
or consider managing <filename>/etc/nix.machines</filename> manually
by setting <option>manualNixMachines</option>. Then you can comment
unavailable buildmachines.
";
};
manualNixMachines = mkOption {
default = false;
description = "
Whether to manually manage the list of buildmachines used in distributed
builds in /etc/nix.machines.
";
};
daemonNiceLevel = mkOption {
default = 10;
description = "
Nix daemon process priority. This priority propagates to build processes.
0 is the default Unix process priority, 20 is the lowest.
";
};
daemonIONiceLevel = mkOption {
default = 7;
description = "
Nix daemon process I/O priority. This priority propagates to build processes.
0 is the default Unix process I/O priority, 7 is the lowest.
";
};
buildMachines = mkOption {
example = [
{ hostName = "voila.labs.cs.uu.nl";
sshUser = "nix";
sshKey = "/root/.ssh/id_buildfarm";
system = "powerpc-darwin";
maxJobs = 1;
}
{ hostName = "linux64.example.org";
sshUser = "buildfarm";
sshKey = "/root/.ssh/id_buildfarm";
system = "x86_64-linux";
maxJobs = 2;
}
];
description = "
This option lists the machines to be used if distributed
builds are enabled (see
<option>nix.distributedBuilds</option>). Nix will perform
derivations on those machines via SSh by copying the inputs to
the Nix store on the remote machine, starting the build, then
copying the output back to the local Nix store. Each element
of the list should be an attribute set containing the
machine's host name (<varname>hostname</varname>), the user
name to be used for the SSH connection
(<varname>sshUser</varname>), the Nix system type
(<varname>system</varname>, e.g.,
<literal>\"i686-linux\"</literal>), the maximum number of jobs
to be run in parallel on that machine
(<varname>maxJobs</varname>), and the path to the SSH private
key to be used to connect (<varname>sshKey</varname>). The
SSH private key should not have a passphrase, and the
corresponding public key should be added to
<filename>~<replaceable>sshUser</replaceable>/authorized_keys</filename>
on the remote machine.
";
};
proxy = mkOption {
default = "";
description = "
This option specifies the proxy to use for fetchurl. The real effect
is just exporting http_proxy, https_proxy and ftp_proxy with that
value.
";
example = "http://127.0.0.1:3128";
};
# Environment variables for running Nix. !!! Misnomer - it's
# actually a shell script.
envVars = mkOption {
internal = true;
default = {};
type = types.attrs;
description = "Environment variables used by Nix.";
};
nrBuildUsers = mkOption {
default = 10;
description = ''
Number of <literal>nixbld</literal> user accounts created to
perform secure concurrent builds. If you receive an error
message saying that “all build users are currently in use”,
you should increase this value.
'';
};
};
};
###### implementation
config = {
nix.chrootDirs = [ "/dev" "/dev/pts" "/proc" "/bin" ];
environment.etc =
[ { # Nix configuration.
source =
let
# Tricky: if we're using a chroot for builds, then we need
# /bin/sh in the chroot (our own compromise to purity).
# However, since /bin/sh is a symlink to some path in the
# Nix store, which furthermore has runtime dependencies on
# other paths in the store, we need the closure of /bin/sh
# in `build-chroot-dirs' - otherwise any builder that uses
# /bin/sh won't work.
binshDeps = pkgs.writeReferencesToFile config.system.build.binsh;
in
pkgs.runCommand "nix.conf" {extraOptions = cfg.extraOptions; } ''
extraPaths=$(for i in $(cat ${binshDeps}); do if test -d $i; then echo $i; fi; done)
cat > $out <<END
# WARNING: this file is generated.
build-users-group = nixbld
build-max-jobs = ${toString (cfg.maxJobs)}
build-use-chroot = ${if cfg.useChroot then "true" else "false"}
build-chroot-dirs = ${toString cfg.chrootDirs} $(echo $extraPaths)
$extraOptions
END
'';
target = "nix/nix.conf";
}
]
++ optional (cfg.distributedBuilds && !cfg.manualNixMachines)
{ # List of machines for distributed Nix builds in the format expected
# by build-remote.pl.
source = pkgs.writeText "nix.machines"
(concatStrings (map (machine:
"${machine.sshUser}@${machine.hostName} "
+ (if machine ? system then machine.system else concatStringsSep "," machine.systems)
+ " ${machine.sshKey} ${toString machine.maxJobs} "
+ (if machine ? speedFactor then toString machine.speedFactor else "1" )
+ "\n"
) cfg.buildMachines));
target = "nix.machines";
};
boot.systemd.units."nix-daemon.socket" =
{ wantedBy = [ "sockets.target" ];
text =
''
[Unit]
Description=Nix Daemon Socket
Before=multi-user.target
[Socket]
ListenStream=/nix/var/nix/daemon-socket/socket
'';
};
boot.systemd.services."nix-daemon.service" =
{ description = "Nix Daemon";
path = [ nix pkgs.openssl pkgs.utillinux ]
++ optionals cfg.distributedBuilds [ pkgs.openssh pkgs.gzip ];
environment = cfg.envVars;
serviceConfig =
''
ExecStart=${nix}/bin/nix-worker --daemon
KillMode=process
PIDFile=/run/sshd.pid
Nice=${toString cfg.daemonNiceLevel}
IOSchedulingPriority=${toString cfg.daemonIONiceLevel}
LimitNOFILE=4096
'';
};
nix.envVars =
{ NIX_CONF_DIR = "/etc/nix";
# Enable the copy-from-other-stores substituter, which allows builds
# to be sped up by copying build results from remote Nix stores. To
# do this, mount the remote file system on a subdirectory of
# /var/run/nix/remote-stores.
NIX_OTHER_STORES = "/var/run/nix/remote-stores/*/nix";
}
// optionalAttrs cfg.distributedBuilds {
NIX_BUILD_HOOK = "${config.environment.nix}/libexec/nix/build-remote.pl";
NIX_REMOTE_SYSTEMS = "/etc/nix.machines";
NIX_CURRENT_LOAD = "/var/run/nix/current-load";
}
# !!! These should not be defined here, but in some general proxy configuration module!
// optionalAttrs (cfg.proxy != "") {
http_proxy = cfg.proxy;
https_proxy = cfg.proxy;
ftp_proxy = cfg.proxy;
};
environment.shellInit =
''
# Set up the environment variables for running Nix.
${concatMapStrings (n: "export ${n}=\"${getAttr n cfg.envVars}\"\n") (attrNames cfg.envVars)}
# Set up secure multi-user builds: non-root users build through the
# Nix daemon.
if test "$USER" != root; then
export NIX_REMOTE=daemon
else
export NIX_REMOTE=
fi
'';
users.extraUsers = map makeNixBuildUser (range 1 cfg.nrBuildUsers);
system.activationScripts.nix = stringAfter [ "etc" "users" ]
''
# Set up Nix.
chown root:nixbld /nix/store
chmod 1775 /nix/store
# Nix initialisation.
mkdir -m 0755 -p \
/nix/var/nix/gcroots \
/nix/var/nix/temproots \
/nix/var/nix/manifests \
/nix/var/nix/userpool \
/nix/var/nix/profiles \
/nix/var/nix/db \
/nix/var/log/nix/drvs \
/nix/var/nix/channel-cache \
/nix/var/nix/chroots
mkdir -m 1777 -p /nix/var/nix/gcroots/per-user
mkdir -m 1777 -p /nix/var/nix/profiles/per-user
mkdir -m 1777 -p /nix/var/nix/gcroots/tmp
ln -sf /nix/var/nix/profiles /nix/var/nix/gcroots/
ln -sf /nix/var/nix/manifests /nix/var/nix/gcroots/
'';
};
}
|