How to start systemd services provided by packages installed through `nix` on an alien distro?

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1

I am on Debain 11. I use home-manager to install and manage apps.

But the app I installed needs a systemd service to be started.

Trying to start using sudo systemctl start service or systemctl --user start service doesn’t work. Obviously because it’s in a different location. So how can I start it?

  • The app I want to run is cloudflare-warp.
  • It creates a VPN of sorts to encrypt internet traffic on my system.
  • Will installing this app through nix encrypt internet traffic for my whole system or only apps in nix setup?

The systemd file is located in

/nix/store/<cloudflare-warp>/lib/systemd/system/warp-svc.service

$ cat lib/systemd/system/warp-svc.service
[Unit]
Description=Cloudflare Zero Trust Client Daemon
After=pre-network.target

[Service]
Type=simple
ExecStart=/nix/store/w1m15pzzpp3fm8i3c8kyyyc1l3cy6fx6-cloudflare-warp-2022.8.936/bin/warp-svc
DynamicUser=no
CapabilityBoundingSet=CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_SYS_PTRACE
AmbientCapabilities=CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_SYS_PTRACE
StateDirectory=cloudflare-warp
RuntimeDirectory=cloudflare-warp
LogsDirectory=cloudflare-warp
Restart=always

[Install]
WantedBy=multi-user.target
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2

You can copy the .service file to /etc/systemd/system/ and then run systemctl daemon-reload

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3

That could lead to unexpected breakage after the next update and gc.

I’ve never used a setup like this but you could create an environment via nix-env that has the service and its etc dir in it and then symlink the unit file from there. This way you can update this managed nix-env as expected.

2 Likes
4

Better yet SYSTEMD_UNIT_PATH. I’ve done this before, at least for user units, and it works really well.

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5

nix-env solution seems more interesting; I will test the feasibility of the solution suggesting soon.

6

Is this option anyway related to the issue?

Home Manager has an option to automatically set some environment variables that will ease usage of software installed with nix on non-NixOS linux (fixing local issues, settings XDG_DATA_DIRS, etc.):

targets.genericLinux.enable = true;

When I included in my home.nix it even said “Activating reloadSystemd” but nothing happened.

7

First one need to create a service file for cloudflare-warp. For inspiration and guidance look at the services directory on the home-manager repo.

For example look at easyeffects.nix:

[...]
    systemd.user.services.easyeffects = {
      Unit = {
        Description = "Easyeffects daemon";
        Requires = [ "dbus.service" ];
        After = [ "graphical-session-pre.target" ];
        PartOf = [ "graphical-session.target" "pipewire.service" ];
      };

      Install.WantedBy = [ "graphical-session.target" ];

      Service = {
        ExecStart =
          "${pkgs.easyeffects}/bin/easyeffects --gapplication-service ${presetOpts}";
        ExecStop = "${pkgs.easyeffects}/bin/easyeffects --quit";
        Restart = "on-failure";
        RestartSec = 5;
      };
    };
[...]

Unfortunately there isn’t one for cloudflare-warp and I am not knowledgeable enough to create on myself (let me know if you do). So I use the app by other means.*

But if there is one it will work like this:

cloudflare-warp needs to be installed as a service like so in your home.nix:

services.cloudflare-warp.enable = true;

and after you switch your configuration:

home-manager switch

you will see a prompt letting you know how to start the systemd service.

*A quick solution for now would be:

$ sudo which(warp-svc)

# on another terminal

$ warp-cli register #for first time
$ warp-cli connect