Change:
Describe the bug The following snippet: results in services failing to start due to missing config files etc. : : ( fails too, but that could be down to the fact that I haven't plugged the UPS in yet -- but for the record, it complains ) Expected behavior I'd expect the services to start successfully (and probably complain about the missing actual UPS). Notify maintainers (The UPS module appears to have received only drive-by changes for the last several years, so no idea who to bug personally). Metadata system: host os: multi-user?: sandbox: version: channels(root): nixpkgs: Maintainer information:
OK, should've read the whole module: I'm supposed to supply the missing /etc/nut files myself because it's unwise to keep them in the store (they could contain passwords and whatnot, I guess?). Declaring (in the service definitions) the state directory to be but creating for the purpose appears to be a real bug, though :)
Also (sorry for the semi-off-topic) what are best practices for referencing hand-written config files without their contents winding up in the store? Double-symlinking? If this is documented somewhere, then I haven't found where.
I was struggling with the same problem as until I noticed this bug report. After copying and editing , , and from to (and setting on all those files), I was able to get it to work. I think this should be more discoverable. If it's not appropriate to copy those sample files to on the users behalf, there should at least be detailed instructions on the option to explain what else needs to be done.
I marked this as stale due to inactivity. &rarr;
Agreed this should be more discoverable. Perhaps at least could be defaulted to empty and written, since I seem to be getting away without anything in there. In case it helps anyone, I got it working with something like this:
I was hit this bug today, too. Maybe we can fix it by using a startup unit that handles the secrets and setup the state directories like nextcloud or syncthing do
Been working on today and wanted to put some notes here. Using version 2.7.4. First, isn't used by for PIDs and it will try to write to . flags , , may be needed instead of environment variables until a 2.7.5 release. Ref: Using for debug makes it non-forking, requiring a change to the systemd unit . I was able to get to run as non-root: I'm still working on understanding how to manage state directories in NixOS but this was needed:
I set out to get my UPS (cyberpower CP1500 AVR UPS) working with NixOS today. This was the first issue I came across, I figured this was the best place to share my configuration. I probably made this more complex than it needed to be because I have no idea what I am doing, and it is definitely not secure; one problem at a time.
Not stale; still relevant
Thanks for providing your standalone config! I learned a ton tweaking it into a netserver config! The below config creates a working NUT netserver that other machines on your local network can be connected to. The only thing I have yet to figure out is a secure way to include passwords in .nix files that won't show up if I push my local copy to github. Any ideas? If you want to tweak when NUT shuts down your computers you can modify the values of " = <percentage" and " = <seconds" under "directives". SHUTDOWNCMD will be triggered when both conditions are met. The "ignorelb" directive is necessary to have NUT ignore the UPS's defaults. Anyone using this config may want to make sure SHUTDOWNCMD and NOTIFYCMD point to the correct binaries in their filesystem. One other thing of note is to check the value of the "schedulerRules" field under below. You must give it the path to your file. I just put a copy of it inside my /etc/nixos. Could probably add another variable to hold the path for convenience. `
For secrets in nix config, I think the current recommendation is to put it in a separate file and not include it in the repo. See also
I have been using sops-nix to commit encrypted passwords to my NixOS repo, but I have yet to put in the elbow grease to make this work with my upsmon password.
is my attempt at making generate the config files necessary for basic operation. If you are using , could you try out the changes and leave a review? Thanks!

Discussion:
<!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. --> <ins> - The `power.ups` module now generates `upsd.conf`, `upsd.users` and `upsmon.conf` automatically from a set of new configuration options. This breaks compatibility with existing `power.ups` setups where these files were created manually. Back up these files before upgrading NixOS. </ins> - `mkosi` was updated to v19. Parts of the user interface have changed. Consult the [release notes](https://github.com/systemd/mkosi/releases/tag/v19) for a list of changes.

let cfg = config.power.ups; <del> in </del> <ins> defaultPort = 3493; nutFormat = { type = with lib.types; let singleAtom = nullOr (oneOf [ bool int float str ]) // { description = "atom (null, bool, int, float or string)"; }; in attrsOf (oneOf [ singleAtom (listOf (nonEmptyListOf singleAtom)) ]); generate = name: value: let normalizedValue = lib.mapAttrs (key: val: if lib.isList val then forEach val (elem: if lib.isList elem then elem else [elem]) else if val == null then [] else [[val]] ) value; mkValueString = concatMapStringsSep " " (v: let str = generators.mkValueStringDefault {} v; in # Quote the value if it has spaces and isn't already quoted. if (hasInfix " " str) && !(hasPrefix """ str && hasSuffix """ str) then ""${str}"" else str ); in pkgs.writeText name (lib.generators.toKeyValue { mkKeyValue = generators.mkKeyValueDefault { inherit mkValueString; } " "; listsAsDuplicateKeys = true; } normalizedValue); }; installSecrets = source: target: secrets: pkgs.writeShellScript "installSecrets.sh" '' install -m0600 -D ${source} "${target}" ${concatLines (forEach secrets (name: '' ${pkgs.replace-secret}/bin/replace-secret  '@${name}@'  "$CREDENTIALS_DIRECTORY/${name}"  "${target}" ''))} chmod u-w "${target}" ''; upsmonConf = nutFormat.generate "upsmon.conf" cfg.upsmon.settings; upsdUsers = pkgs.writeText "upsd.users" (let # This looks like INI, but it's not quite because the # 'upsmon' option lacks a '='. See: man upsd.users userConfig = name: user: concatStringsSep "n      " (concatLists [ [ "[${name}]" "password = "@upsdusers_password_${name}@"" ] (optional (user.upsmon != null) "upsmon ${user.upsmon}") (forEach user.actions (action: "actions = ${action}")) (forEach user.instcmds (instcmd: "instcmds = ${instcmd}")) ]); in concatStringsSep "nn" (mapAttrsToList userConfig cfg.users)); </ins> <del> let </del> upsOptions = {name, config, ...}: { options = {

}; }; <ins> listenOptions = { options = { address = mkOption { type = types.str; description = lib.mdDoc '' Address of the interface for `upsd` to listen on. See `man upsd.conf` for details. ''; }; port = mkOption { type = types.port; default = defaultPort; description = lib.mdDoc '' TCP port for `upsd` to listen on. See `man upsd.conf` for details. ''; }; }; }; upsdOptions = { options = { enable = mkOption { type = types.bool; defaultText = literalMD "`true` if `mode` is one of `standalone`, `netserver`"; description = mdDoc "Whether to enable `upsd`."; }; listen = mkOption { type = with types; listOf (submodule listenOptions); default = []; example = [ { address = "192.168.50.1"; } { address = "::1"; port = 5923; } ]; description = lib.mdDoc '' Address of the interface for `upsd` to listen on. See `man upsd` for details`. ''; }; extraConfig = mkOption { type = types.lines; default = ""; description = lib.mdDoc '' Additional lines to add to `upsd.conf`. ''; }; }; config = { enable = mkDefault (elem cfg.mode [ "standalone" "netserver" ]); }; }; monitorOptions = { name, config, ... }: { options = { system = mkOption { type = types.str; default = name; description = lib.mdDoc '' Identifier of the UPS to monitor, in this form: `<upsname>[@<hostname>[:<port>]]` See `upsmon.conf` for details. ''; }; powerValue = mkOption { type = types.int; default = 1; description = lib.mdDoc '' Number of power supplies that the UPS feeds on this system. See `upsmon.conf` for details. ''; }; user = mkOption { type = types.str; description = lib.mdDoc '' Username from `upsd.users` for accessing this UPS. See `upsmon.conf` for details. ''; }; passwordFile = mkOption { type = types.str; defaultText = literalMD "power.ups.users.${user}.passwordFile"; description = lib.mdDoc '' The full path to a file containing the password from `upsd.users` for accessing this UPS. The password file is read on service start. See `upsmon.conf` for details. ''; }; type = mkOption { type = types.str; default = "master"; description = lib.mdDoc '' The relationship with `upsd`. See `upsmon.conf` for details. ''; }; }; config = { passwordFile = mkDefault cfg.users.${config.user}.passwordFile; }; }; upsmonOptions = { options = { enable = mkOption { type = types.bool; defaultText = literalMD "`true` if `mode` is one of `standalone`, `netserver`, `netclient`"; description = mdDoc "Whether to enable `upsmon`."; }; monitor = mkOption { type = with types; attrsOf (submodule monitorOptions); default = {}; description = lib.mdDoc '' Set of UPS to monitor. See `man upsmon.conf` for details. ''; }; settings = mkOption { type = nutFormat.type; default = {}; defaultText = literalMD '' { MINSUPPLIES = 1; RUN_AS_USER = "root"; NOTIFYCMD = "''${pkgs.nut}/bin/upssched"; SHUTDOWNCMD = "''${pkgs.systemd}/bin/shutdown now"; } ''; description = mdDoc "Additional settings to add to `upsmon.conf`."; example = literalMD '' { MINSUPPLIES = 2; NOTIFYFLAG = [ [ "ONLINE" "SYSLOG+EXEC" ] [ "ONBATT" "SYSLOG+EXEC" ] ]; } ''; }; }; config = { enable = mkDefault (elem cfg.mode [ "standalone" "netserver" "netclient" ]); settings = { RUN_AS_USER = "root"; # TODO: replace 'root' by another username. MINSUPPLIES = mkDefault 1; NOTIFYCMD = mkDefault "${pkgs.nut}/bin/upssched"; SHUTDOWNCMD = mkDefault "${pkgs.systemd}/bin/shutdown now"; MONITOR = flip mapAttrsToList cfg.upsmon.monitor (name: monitor: with monitor; [ system powerValue user ""@upsmon_password_${name}@"" type ]); }; }; }; userOptions = { options = { passwordFile = mkOption { type = types.str; description = lib.mdDoc '' The full path to a file that contains the user's (clear text) password. The password file is read on service start. ''; }; actions = mkOption { type = with types; listOf str; default = []; description = lib.mdDoc '' Allow the user to do certain things with upsd. See `man upsd.users` for details. ''; }; instcmds = mkOption { type = with types; listOf str; default = []; description = lib.mdDoc '' Let the user initiate specific instant commands. Use "ALL" to grant all commands automatically. For the full list of what your UPS supports, use "upscmd -l". See `man upsd.users` for details. ''; }; upsmon = mkOption { type = with types; nullOr str; default = null; description = lib.mdDoc '' Add the necessary actions for a upsmon process to work. See `man upsd.users` for details. ''; }; }; }; </ins> in

# powerManagement.powerDownCommands power.ups = { <del> enable = mkOption { default = false; type = with types; bool; description = lib.mdDoc '' Enables support for Power Devices, such as Uninterruptible Power Supplies, Power Distribution Units and Solar Controllers. ''; }; </del> <ins> enable = mkEnableOption (lib.mdDoc '' Enables support for Power Devices, such as Uninterruptible Power Supplies, Power Distribution Units and Solar Controllers. ''); </ins> <del> # This option is not used yet. </del> mode = mkOption { default = "standalone"; <del> type = types.str; </del> <ins> type = types.enum [ "none" "standalone" "netserver" "netclient" ]; </ins> description = lib.mdDoc '' The MODE determines which part of the NUT is to be started, and which configuration files must be modified.

''; }; <ins> openFirewall = mkOption { type = types.bool; default = false; description = lib.mdDoc '' Open ports in the firewall for `upsd`. ''; }; </ins> maxStartDelay = mkOption { default = 45;

''; }; <ins> upsmon = mkOption { default = {}; description = lib.mdDoc '' Options for the `upsmon.conf` configuration file. ''; type = types.submodule upsmonOptions; }; upsd = mkOption { default = {}; description = lib.mdDoc '' Options for the `upsd.conf` configuration file. ''; type = types.submodule upsdOptions; }; </ins> ups = mkOption { default = {}; # see nut/etc/ups.conf.sample

type = with types; attrsOf (submodule upsOptions); }; <ins> users = mkOption { default = {}; description = lib.mdDoc '' Users that can access upsd. See `man upsd.users`. ''; type = with types; attrsOf (submodule userOptions); }; </ins> }; }; config = mkIf cfg.enable { <ins> assertions = [ (let totalPowerValue = foldl' add 0 (map (monitor: monitor.powerValue) (attrValues cfg.upsmon.monitor)); minSupplies = cfg.upsmon.settings.MINSUPPLIES; in mkIf cfg.upsmon.enable { assertion = totalPowerValue >= minSupplies; message = '' `power.ups.upsmon`: Total configured power value (${toString totalPowerValue}) must be at least MINSUPPLIES (${toString minSupplies}). ''; }) ]; </ins> environment.systemPackages = [ pkgs.nut ]; <del> systemd.services.upsmon = { </del> <ins> networking.firewall = mkIf cfg.openFirewall { allowedTCPPorts = if cfg.upsd.listen == [] then [ defaultPort ] else unique (forEach cfg.upsd.listen (listen: listen.port)); }; systemd.services.upsmon = let secrets = mapAttrsToList (name: monitor: "upsmon_password_${name}") cfg.upsmon.monitor; createUpsmonConf = installSecrets upsmonConf "/run/nut/upsmon.conf" secrets; in { enable = cfg.upsmon.enable; </ins> description = "Uninterruptible Power Supplies (Monitor)"; after = [ "network.target" ]; wantedBy = [ "multi-user.target" ]; <del> serviceConfig.Type = "forking"; script = "${pkgs.nut}/sbin/upsmon"; environment.NUT_CONFPATH = "/etc/nut/"; environment.NUT_STATEPATH = "/var/lib/nut/"; </del> <ins> serviceConfig = { Type = "forking"; ExecStartPre = "${createUpsmonConf}"; ExecStart = "${pkgs.nut}/sbin/upsmon"; ExecReload = "${pkgs.nut}/sbin/upsmon -c reload"; LoadCredential = mapAttrsToList (name: monitor: "upsmon_password_${name}:${monitor.passwordFile}") cfg.upsmon.monitor; }; environment.NUT_CONFPATH = "/etc/nut"; environment.NUT_STATEPATH = "/var/lib/nut"; </ins> }; <del> systemd.services.upsd = { </del> <ins> systemd.services.upsd = let secrets = mapAttrsToList (name: user: "upsdusers_password_${name}") cfg.users; createUpsdUsers = installSecrets upsdUsers "/run/nut/upsd.users" secrets; in { enable = cfg.upsd.enable; </ins> description = "Uninterruptible Power Supplies (Daemon)"; after = [ "network.target" "upsmon.service" ]; wantedBy = [ "multi-user.target" ]; <del> serviceConfig.Type = "forking"; # TODO: replace 'root' by another username. script = "${pkgs.nut}/sbin/upsd -u root"; environment.NUT_CONFPATH = "/etc/nut/"; environment.NUT_STATEPATH = "/var/lib/nut/"; </del> <ins> serviceConfig = { Type = "forking"; ExecStartPre = "${createUpsdUsers}"; # TODO: replace 'root' by another username. ExecStart = "${pkgs.nut}/sbin/upsd -u root"; ExecReload = "${pkgs.nut}/sbin/upsd -c reload"; LoadCredential = mapAttrsToList (name: user: "upsdusers_password_${name}:${user.passwordFile}") cfg.users; }; environment.NUT_CONFPATH = "/etc/nut"; environment.NUT_STATEPATH = "/var/lib/nut"; restartTriggers = [ config.environment.etc."nut/upsd.conf".source ]; </ins> }; systemd.services.upsdrv = { <ins> enable = cfg.upsd.enable; </ins> description = "Uninterruptible Power Supplies (Register all UPS)"; after = [ "upsd.service" ]; wantedBy = [ "multi-user.target" ]; <del> # TODO: replace 'root' by another username. script = "${pkgs.nut}/bin/upsdrvctl -u root start"; </del> serviceConfig = { Type = "oneshot"; RemainAfterExit = true; <ins> # TODO: replace 'root' by another username. ExecStart = "${pkgs.nut}/bin/upsdrvctl -u root start"; </ins> }; <del> environment.NUT_CONFPATH = "/etc/nut/"; environment.NUT_STATEPATH = "/var/lib/nut/"; </del> <ins> environment.NUT_CONFPATH = "/etc/nut"; environment.NUT_STATEPATH = "/var/lib/nut"; </ins> }; environment.etc = {

'' maxstartdelay = ${toString cfg.maxStartDelay} <del> ${flip concatStringsSep (forEach (attrValues cfg.ups) (ups: ups.summary)) " "} </del> <ins> ${concatStringsSep "nn" (forEach (attrValues cfg.ups) (ups: ups.summary))} ''; "nut/upsd.conf".source = pkgs.writeText "upsd.conf" '' ${concatStringsSep "n" (forEach cfg.upsd.listen (listen: "LISTEN ${listen.address} ${toString listen.port}"))} ${cfg.upsd.extraConfig} </ins> ''; "nut/upssched.conf".source = cfg.schedulerRules; <del> # These file are containing private information and thus should not # be stored inside the Nix store. /* "nut/upsd.conf".source = ""; "nut/upsd.users".source = ""; "nut/upsmon.conf".source = ""; */ </del> <ins> "nut/upsd.users".source = "/run/nut/upsd.users"; "nut/upsmon.conf".source = "/run/nut/upsmon.conf"; </ins> }; power.ups.schedulerRules = mkDefault "${pkgs.nut}/etc/upssched.conf.sample"; systemd.tmpfiles.rules = [ "d /var/state/ups -" <ins> "d /var/lib/nut 700" </ins> ];