How to create user systemd service

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1

Hello!

I just installed NixOS on my laptop and began the adventure. I was trying to create a user service in configuration.nix file. I put this in my file:

  systemd.user.services.onedrive-UMFC = {
    enable = true;
    description = "OneDrive Client for Linux running for jeansib";
    after = [ "network-online.target" ];
    wantedBy = [ "multi-user.target" ];
    serviceConfig = {
      ProtectSystem = "full";
      ProtectHostname = "true";
      ProtectKernelTunables = "true";
      ProtectControlGroups = "true";
      RestrictRealtime = "true";
      ExecStartPre = ''/run/current-system/sw/bin/sleep'';
      ExecStart = ''/run/current-system/sw/bin/onedrive --monitor --confdir=/home/jeansib/.config/oned>
      User = "jeansib";
      Group = "users";
      Restart = "on-failure";
      RestartSec = "3";
      RestartPreventExitStatus = "126";
      TimeoutStopSec = "90";
    };
  };

Then I ran nixos-rebuild switch and didn’t get any error.

But now, where is this service file stored? When I run systemctl status onedrive-UMFC I get an error saying that such unit doesn’t exist.

Can anyone help me please?

Miro

2

Command is missing --user.

3

Thank you, if I understand correctly I had to add --user flag to systemctl command. But when I do, I get this error:

[root@nixos:~]# systemctl --user list-units 
Failed to connect to user scope bus via local transport: No medium found

[root@nixos:~]# systemctl status --user onedrive-UMFC
Failed to connect to user scope bus via local transport: No medium found

[root@nixos:~]#

What can that mean?

4

Did you upgrade systemd recently and not reboot yet?

Also, you need to run this as a user that will run the service, it’s a user unit.

5

systemctl --user shows the user’s services for the current user. You’re running that command as root and I presume you intend for the service to work in a regular user’s scope.

Run this command(systemctl --user list-units ) as your normal user.

About the error message in your post:

If you become root through sudo, systemctl --user will not work at all:

❯ sudo -i       

root in ~ 
❯ systemctl --user status               
Failed to connect to user scope bus via local transport: No medium found

You can get this working if you use machinectl shell <username>@ $(which bash) instead of sudo, but that’s most likely not what you want here.

Just for completeness sake, here's how to call systemctl --user in an interactive shell for a different user 
❯ whoami                     
spacecadet

❯ sudo -i # start login session as root

❯ whoami                     
root

❯ systemctl --user status
Failed to connect to user scope bus via local transport: No medium found

❯ exit # back to the normal user
❯ machinectl shell root@ $(which bash)
# < auth >
❯ whoami                     
root
❯ systemctl --user status
WARNING: terminal is not fully functional
Press RETURN to continue 
● uranium
    State: running
    Units: 177 loaded (incl. loaded aliases)
     Jobs: 0 queued
   Failed: 0 units
    Since: Fri 2024-12-20 11:57:17 PST; 16s ago
  systemd: 256.8
   CGroup: /user.slice/user-0.slice/user@0.service
<the output>

Now from root:

❯ whoami                                                                         
root

❯ machinectl shell spacecadet@ $(which bash)
Connected to the local host. Press ^] three times within 1s to exit session.

❯ systemctl --user status
● uranium
    State: degraded
    Units: 237 loaded (incl. loaded aliases)
     Jobs: 0 queued
   Failed: 1 units
<the output>
2 Likes
6

Thank you very much for your answers, I am deeply grateful.

I didn’t know of the --user option, I always used systemctl enable --now unit-name@user-name.service to enable and start user units.

I changed to unstable channel of Nix, but I rebooted.

Now I can see my unit running:

[jeansib@nixos:~]$ systemctl --user status onedrive-UMFC.service 
● onedrive-UMFC.service - OneDrive Client for Linux running for jeansib
     Loaded: loaded (/home/jeansib/.config/systemd/user/onedrive-UMFC.service; enabled; preset: ignored)
     Active: activating (auto-restart) (Result: exit-code) since Sat 2024-12-21 09:18:33 CET; 1s ago
 Invocation: bb4a32cc3ac7424c88aaebc395976f88
    Process: 10834 ExecStartPre=/run/current-system/sw/bin/sleep (code=exited, status=216/GROUP)
   Mem peak: 1.5M
        CPU: 7ms
[jeansib@nixos:~]$

If you would help me further, I would appreciate that.
I see that there is some kind of group problem with this unit. I was tinkering a little bit with configuration and now it looks like this:

  systemd.user.services.onedrive-UMFC = {
    enable = true;
    description = "OneDrive Client for Linux running for jeansib";
    after = [ "network-online.target" ];
    wantedBy = [ "default.target" ];
    serviceConfig = {
      ProtectSystem = "full";
      ProtectHostname = "true";
      ProtectKernelTunables = "true";
#      ProtectControlGroups = "true";
      RestrictRealtime = "true";
      ExecStartPre = ''/run/current-system/sw/bin/sleep'';
      ExecStart = ''/run/current-system/sw/bin/onedrive --monitor --confdir=/home/jeansib/.config/onedrive/onedrive-UMFC/'';
      User = "jeansib";
#      Group = "jeansib";
      Restart = "on-failure";
      RestartSec = "3";
      RestartPreventExitStatus = "126";
      TimeoutStopSec = "90";
    };
  };

First I changed group from “users” to “jeansib” and then I tried to eliminate all group lines thinking that maybe it somehow broke the unit.
When I run try to start the service I get this error:

[jeansib@nixos:~]$ systemctl --user start onedrive-UMFC.service 
Job for onedrive-UMFC.service failed because the control process exited with error code.
See "systemctl --user status onedrive-UMFC.service" and "journalctl --user -xeu onedrive-UMFC.service" for details.
[jeansib@nixos:~]$

Running journalctl --user -xeu … gives me this:

gru 21 09:27:51 nixos (sleep)[11787]: onedrive-UMFC.service: Failed to determine supplementary groups: Operation not permitted
gru 21 09:27:51 nixos (sleep)[11787]: onedrive-UMFC.service: Failed at step GROUP spawning /run/current-system/sw/bin/sleep: Operation not permitted
7

You cannot set User on a user systemd service. It will necessarily run as your user.

8

Okay, so this whole systemd block should be inside users.users.jeansib{} block?

9

No. Using systemd.user.* hierarchy creates it for all (regular) users on the system. (More accurately it puts it in /run/current-system/sw/lib/systemd/user/ which is used by all systemd user sessions.)

If you want per-user control I believe you have to use something like home-manager at this time.

10

Okay, but can I disable for specific user this unit?

11

You could mask the unit in that user’s systemd directories, but you would still need to do that with home-manager (or - gasp - manually) afaik.

Regardless, they would have permissions to re-enable it - this really looks like the type of unit that should be done with home-manager in your home directory, so your user is the only user with any control over or insight into it.

Also, use %h instead of an absolute path for your home directory in systemd units, that way they are portable, and use ${package}/bin/binary (or add the packages to path and don’t use an absolute path) instead of /run/current-system, otherwise you’re relying on your config just happening to install those binaries.

12

Thank you for your kind answers! I decided to go with home-manager. This is my config:

{config, pkgs, ...}:
{
  home = {
    stateVersion = "24.11";
    username = "jeansib";
    homeDirectory = "/home/jeansib";
  };

  systemd.user.services.onedrive-UMFC = {
    Unit = {
      Description = "OneDrive client for Linux";
    };
    Service = {
      ProtectSystem = "full";
      ProtectHostname = true;
      ProtectKernelTunables = true;
      ProtectControlGroups = true;
      RestrictRealtime = true;
      Group = "users";
      ExecStartPre = "sleep 15";
      ExecStart= ''${pkgs.onedrive}/bin/onedrive --monitor --confdir=/home/jeansib/.config/onedrive/onedrive-UMFC'';
      Restart = "on-failure";
      RestartSec = 3;
      # Do not restart the service if a --resync is required which is done via a 126 exit code
      RestartPreventExitStatus = 126;
      # Time to wait for the service to stop gracefully before forcefully terminating it
      TimeoutStopSec = 90;
    };
    Install = {
      WantedBy = [ "default.target" ];
    };
  };
}

But when I try to switch I get this error:

[jeansib@nixos:~]$ home-manager switch
/nix/store/hiwz93nvmz33h6ccy85ai37dng94dwb0-home-manager-generation
Starting Home Manager activation
Activating checkFilesChanged
Activating checkLinkTargets
Existing file '/home/jeansib/.config/systemd/user/onedrive-UMFC.service' is in the way of '/nix/store/rfg38jpl2msc7kllzvgdgqydrycvv269-home-manager-files/.config/systemd/user/onedrive-UMFC.service'
Please do one of the following:
- Move or remove the above files and try again.
- In standalone mode, use 'home-manager switch -b backup' to back up
  files automatically.
- When used as a NixOS or nix-darwin module, set
    'home-manager.backupFileExtension'
  to, for example, 'backup' and rebuild.
[jeansib@nixos:~]$

What does it mean? I tried to add to /etc/nixos/configuration.nix line:

home-manager.backupFileExtension = "backup";

but that didn’t work…

13

Guys! I did it! I think that there was somewhere still the unit I created with /etc/nixos/configuration.nix file, I had to disable it and run home-manager switch -b backup and now this unit works! But also I had to comment out ExecStartPre:

  systemd.user.services.onedrive-UMFC = {
    Unit = {
      Description = "OneDrive client for Linux";
    };
    Service = {
      ProtectSystem = "full";
      ProtectHostname = true;
      ProtectKernelTunables = true;
      ProtectControlGroups = true;
      RestrictRealtime = true;
      Group = "users";
#      ExecStartPre = ''sleep 15'';
      ExecStart= ''${pkgs.onedrive}/bin/onedrive --monitor --confdir=/home/kazimierzkrauze/.config/onedrive/onedrive-UMFC'';
      Restart = "on-failure";
      RestartSec = 3;
      # Do not restart the service if a --resync is required which is done via a 126 exit code
      RestartPreventExitStatus = 126;
      # Time to wait for the service to stop gracefully before forcefully terminating it
      TimeoutStopSec = 90;
    };
    Install = {
      WantedBy = [ "default.target" ];
    };
  };

I tried to enter ‘’${pkgs.sleep}…‘’ but that didn’t work.

14

Try "${pkgs.coreutils}/bin/sleep 15" instead.

15

Thank you, that helped!

16

This was what fixed it; the error message says you already put a systemd unit in your user’s directory manually, and home-manager refused to overwrite such files in case they contain something important.

Adding the -b flag just renames the file, so you probably have a subtly different, inert copy of the unit in there.

17

Well, that’s strange, I did try to use this command and the output was the same, it was not until I manually disabled this unit that home-manager switch worked. But maybe not… I found that sometimes I have to just try again and it works.

18

The same message would indeed appear if your NixOS config created that file somehow, but I didn’t think NixOS modules touched user directories. Maybe systemd creates a symlink to the system-wide file?

19

But if I declare in /etc/nixos/conf.nix user service then where is it stored?

20

Did you run systemctl enable at any point?