nixpkgs/nixos/modules/services/networking/ntp/chrony.nix

124 lines
3.3 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.chrony;
stateDir = "/var/lib/chrony";
keyFile = "${stateDir}/chrony.keys";
configFile = pkgs.writeText "chrony.conf" ''
${concatMapStringsSep "\n" (server: "server " + server + " iburst") cfg.servers}
${optionalString
(cfg.initstepslew.enabled && (cfg.servers != []))
"initstepslew ${toString cfg.initstepslew.threshold} ${concatStringsSep " " cfg.servers}"
}
driftfile ${stateDir}/chrony.drift
keyfile ${keyFile}
${optionalString (!config.time.hardwareClockInLocalTime) "rtconutc"}
${cfg.extraConfig}
'';
chronyFlags = "-n -m -u chrony -f ${configFile} ${toString cfg.extraFlags}";
in
{
options = {
services.chrony = {
enable = mkOption {
type = types.bool;
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 = config.networking.timeServers;
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)
};
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 {
type = types.lines;
default = "";
description = ''
Extra configuration directives that should be added to
<literal>chrony.conf</literal>
'';
};
extraFlags = mkOption {
default = [];
example = [ "-s" ];
type = types.listOf types.str;
description = "Extra flags passed to the chronyd command.";
};
};
};
config = mkIf cfg.enable {
meta.maintainers = with lib.maintainers; [ thoughtpolice ];
environment.systemPackages = [ pkgs.chrony ];
users.groups.chrony.gid = config.ids.gids.chrony;
users.users.chrony =
{ uid = config.ids.uids.chrony;
group = "chrony";
description = "chrony daemon user";
home = stateDir;
};
services.timesyncd.enable = mkForce false;
systemd.services.systemd-timedated.environment = { SYSTEMD_TIMEDATED_NTP_SERVICES = "chronyd.service"; };
systemd.tmpfiles.rules = [
"d ${stateDir} 0755 chrony chrony - -"
"f ${keyFile} 0640 chrony chrony -"
];
systemd.services.chronyd =
{ description = "chrony NTP daemon";
wantedBy = [ "multi-user.target" ];
wants = [ "time-sync.target" ];
before = [ "time-sync.target" ];
after = [ "network.target" ];
conflicts = [ "ntpd.service" "systemd-timesyncd.service" ];
path = [ pkgs.chrony ];
unitConfig.ConditionCapability = "CAP_SYS_TIME";
serviceConfig =
{ Type = "simple";
ExecStart = "${pkgs.chrony}/bin/chronyd ${chronyFlags}";
ProtectHome = "yes";
ProtectSystem = "full";
PrivateTmp = "yes";
};
};
};
}