nixpkgs/nixos/modules/services/system/nscd.nix
Nikolay Amiantov b451eca621 nscd service: fix ordering and start automatically
During working on #150837 I discovered that `google-oslogin` test
started failing, and so did some of my development machines. Turns out
it was because nscd doesn't start by default; rather it's wanted by
NSS lookup targets, which are not always fired up.

To quote from section on systemd.special(7) on `nss-user-lookup.target`:

> All services which provide parts of the user/group database should be
> ordered before this target, and pull it in.

Following this advice and comparing our unit to official `sssd.service`
unit (which is a similar service), we now pull NSS lookup targets from
the service, while starting it with `multi-user.target`.
2022-01-10 22:45:12 +03:00

88 lines
2.4 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
nssModulesPath = config.system.nssModules.path;
cfg = config.services.nscd;
nscd = if pkgs.stdenv.hostPlatform.libc == "glibc"
then pkgs.stdenv.cc.libc.bin
else pkgs.glibc.bin;
in
{
###### interface
options = {
services.nscd = {
enable = mkOption {
type = types.bool;
default = true;
description = ''
Whether to enable the Name Service Cache Daemon.
Disabling this is strongly discouraged, as this effectively disables NSS Lookups
from all non-glibc NSS modules, including the ones provided by systemd.
'';
};
config = mkOption {
type = types.lines;
default = builtins.readFile ./nscd.conf;
description = "Configuration to use for Name Service Cache Daemon.";
};
};
};
###### implementation
config = mkIf cfg.enable {
environment.etc."nscd.conf".text = cfg.config;
systemd.services.nscd =
{ description = "Name Service Cache Daemon";
before = [ "nss-lookup.target" "nss-user-lookup.target" ];
wants = [ "nss-lookup.target" "nss-user-lookup.target" ];
wantedBy = [ "multi-user.target" ];
environment = { LD_LIBRARY_PATH = nssModulesPath; };
restartTriggers = [
config.environment.etc.hosts.source
config.environment.etc."nsswitch.conf".source
config.environment.etc."nscd.conf".source
];
# We use DynamicUser because in default configurations nscd doesn't
# create any files that need to survive restarts. However, in some
# configurations, nscd needs to be started as root; it will drop
# privileges after all the NSS modules have read their configuration
# files. So prefix the ExecStart command with "!" to prevent systemd
# from dropping privileges early. See ExecStart in systemd.service(5).
serviceConfig =
{ ExecStart = "!@${nscd}/sbin/nscd nscd";
Type = "forking";
DynamicUser = true;
RuntimeDirectory = "nscd";
PIDFile = "/run/nscd/nscd.pid";
Restart = "always";
ExecReload =
[ "${nscd}/sbin/nscd --invalidate passwd"
"${nscd}/sbin/nscd --invalidate group"
"${nscd}/sbin/nscd --invalidate hosts"
];
};
};
};
}