nixpkgs/nixos/modules/services/networking/chrony.nix
Eelco Dolstra 29027fd1e1 Rewrite ‘with pkgs.lib’ -> ‘with lib’
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
2014-04-14 16:26:48 +02:00

119 lines
2.5 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
inherit (pkgs) chrony;
stateDir = "/var/lib/chrony";
chronyUser = "chrony";
cfg = config.services.chrony;
configFile = pkgs.writeText "chrony.conf" ''
${toString (map (server: "server " + server + "\n") cfg.servers)}
${optionalString cfg.initstepslew.enabled ''
initstepslew ${toString cfg.initstepslew.threshold} ${toString (map (server: server + " ") cfg.initstepslew.servers)}
''}
driftfile ${stateDir}/chrony.drift
${optionalString (!config.time.hardwareClockInLocalTime) "rtconutc"}
${cfg.extraConfig}
'';
chronyFlags = "-m -f ${configFile} -u ${chronyUser}";
in
{
###### interface
options = {
services.chrony = {
enable = mkOption {
default = false;
description = ''
Whether to synchronise your machine's time using chrony.
Make sure you disable NTP if you enable this service.
'';
};
servers = mkOption {
default = [
"0.pool.ntp.org"
"1.pool.ntp.org"
"2.pool.ntp.org"
];
description = ''
The set of NTP servers from which to synchronise.
'';
};
initstepslew = mkOption {
default = {
enabled = true;
threshold = 1000; # by default, same threshold as 'ntpd -g' (1000s)
servers = cfg.servers;
};
description = ''
Allow chronyd to make a rapid measurement of the system clock error at
boot time, and to correct the system clock by stepping before normal
operation begins.
'';
};
extraConfig = mkOption {
default = "";
description = ''
Extra configuration directives that should be added to
<literal>chrony.conf</literal>
'';
};
};
};
###### implementation
config = mkIf config.services.chrony.enable {
# Make chronyc available in the system path
environment.systemPackages = [ pkgs.chrony ];
users.extraUsers = singleton
{ name = chronyUser;
uid = config.ids.uids.chrony;
description = "chrony daemon user";
home = stateDir;
};
jobs.chronyd =
{ description = "chrony daemon";
wantedBy = [ "ip-up.target" ];
partOf = [ "ip-up.target" ];
path = [ chrony ];
preStart =
''
mkdir -m 0755 -p ${stateDir}
chown ${chronyUser} ${stateDir}
'';
exec = "chronyd -n ${chronyFlags}";
};
};
}