Linux Questions @lemmy.zip Telorand @reddthat.com 5 mo. ago

[Solved] How can I make a custom .service run as root?

cross-posted from: https://reddthat.com/post/21668140

I have a VPN daemon that needs to run before the client will work. Normally, this would have been set up automatically by its install script, but the system is immutable.

I've created the systemd service via sysyemctl edit --force --full daemon.service with the following parameters:
[Unit] 
Description=Blah
After=network-online.target

[Service]
User=root
Group=root
ExecStart=/usr/bin/env /path/to/daemon

[Install]
WantedBy=multi-user.target
I've verified that the daemon is actually executable, and it runs fine when I manually call it via sudo daemon. When I try to run it with sudo systemctl enable --now daemon.service, it exits with error code 126.

What am I missing?

Edit: Typo, and added the relevant user and group to the Service section. Still throwing a 126.

Solution: the system wanted /usr/bin/env in ExecStart to launch the binary. The .service file above has been edited to show the working solution.

19 comments

If that is your full .service file you are missing the directive to tell the daemon what user to run under. Under service try adding

User=root

Group=root

Before the ExecStart command line.
- Is that necessary for processes running as root? AfaIk, root is default.
  
  Keywords should be in CamelCase format, thus the space in Wanted By is wrong.
  
  Honestly can't believe I completely missed the space in Wanted By. This is likely the bigger culprit to the failed to run error. Poster above me is correct should read
  
  WantedBy
  
  Foiled by autocorrect! There's no space in the original file, and I've edited my post to reflect that.
- On that, make sure it's in the root systemd path. Something like /etc/systemd/system/blah.service, placing it in the user systemd service path (~/.config/systemd/user/) will cause permission errors as it'll try accessing the root user from the current user.
  
  Thanks, I verified that it's in the correct place. Still throwing a 126 (see the modifications in the edit).
- I added the relevant user and group, and it's still throwing a 126. I checked the daemon itself, and it looks like it's a pre-compiled binary. Manually running /bin/bash /path/to/daemon gives the same error, but sudo /path/to/daemon starts the daemon.
- Does the command in ExecStart work in a root environment, e.g. sudo -i?

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