Score:3

Ubuntu

Unable to create SystemD user service "Failed to connect to bus: Permission denied"

Gecko

5/30/24, 1:13 PM

Trying to run

systemctl --user start my-service.service

on Ubuntu server 20.04 as a non-root user I get

Failed to connect to bus: Permission denied

Even just

systemctl --user

gives the same error.

The user was created with adduser --disabled-login my-user and is accessed by running su my-user.

Based on what I found researching this issue it seems that some environment variable is not properly initialised when doing su as opposed to "logging in" that causes this.

Show your work:

libpam-systemd as suggested here is already installed
Setting XDG_RUNTIME_DIR as suggested here did not work

526

1 + 2

server

systemd

20.04

steeldriver

5/30/24, 8:39 PM

I'm not really sure how to interpret it, but this seems related [Why isn't a systemd user session started by `su`?](https://unix.stackexchange.com/questions/703410/why-isnt-a-systemd-user-session-started-by-su)

Gecko

6/7/24, 3:33 PM

Looking back at this, running `su --login` instead of just `su` might've also done the trick.

Score:1

Ubuntu

Raffa

5/31/24, 11:47 AM

Your user service is, most likely, not starting because the needed path to the user specific bus socket file at /run/user/$UID/bus(which is part of the user-runtime environment) is not properly set in the environment variable DBUS_SESSION_BUS_ADDRESS ... That should be set to something similar to this:

$ echo "$DBUS_SESSION_BUS_ADDRESS"
unix:path=/run/user/1000/bus

If not set, then set and export it like so:

export DBUS_SESSION_BUS_ADDRESS="unix:path=/run/user/$UID/bus"

Then, try starting your user service again.

Notice: This, however, requires a user-runtime environment which is set mainly by the service user@$UID.service(and company)($UID is the invoking user's ID) ... Which might as well be a culprit in your situation … If it's not running, start it first with sudo(from an administrator user account) (replacing the example 1003 with the actual ID of the user) like so:

sudo systemctl start [email protected]

+ 2

Raffa

5/31/24, 1:26 PM

I started tracing the end user error which lead me to eventually discussing the user-runtime environment at the end of my answer … Now I think I should have written the answer bottom-up :-) … Make sure you read the **notice** part first.

Gecko

6/4/24, 9:46 PM

Running `sudo systemctl start [email protected]` and adding `export DBUS_SESSION_BUS_ADDRESS="unix:path=/run/user/$UID/bus"` seems to have done the trick. Thanks! :D

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Unable to create SystemD user service "Failed to connect to bus: Permission denied"

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