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I had posted this answer to my question sometime ago. Now, due to evolving needs, I would like to make the VNC server available to multiple users. The service should start at startup, and be available.

I tried to pass various arguments to the User= directive (under the [Service] section). I tried User=$USER, User=%u, and few other alternatives. None worked. Per the documentation, User should be a unitary and static. However, the documentation also mentions a DynamicUser just below the User= directive, which is unfortunately beyond my understanding of systemd. (Perhaps I should try User=$USER or User=%u and DynamicUser=true? Doesn't work.)

Is there a way to create a systemd template unit file for multiple users?

Ps. Seems like it could be done with the older init.d

Kartik
  • 301

1 Answers1

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It's not possible to pass multiple parameters to the a systemd template (see related mailing list discussion). However, since we have only two parameters and one is the username, it makes sense to make it a user service instead of a system service.

User services can be run at boot if you enable lingering for those users:

sudo loginctl enable-linger username

From man loginctl:

enable-linger [USER...], disable-linger [USER...]
   Enable/disable user lingering for one or more users. If enabled for
   a specific user, a user manager is spawned for the user at boot and
   kept around after logouts. This allows users who are not logged in
   to run long-running services. Takes one or more user names or
   numeric UIDs as argument. If no argument is specified,
   enables/disables lingering for the user of the session of the
   caller.

You can create a user service at /etc/systemd/user, which would look like (adapting your earlier service): 

[Unit]
Description=Start TigerVNC Server at startup
After=syslog.target network.target

[Service]
Type=forking
PAMName=login
PIDFile=%h/.vnc/%H:%i.pid
ExecStartPre=-/usr/bin/vncserver -kill :%i > /dev/null 2>&1
ExecStart=/usr/bin/vncserver :%i -depth 24 -geometry 1920x1080 -nolisten tcp -localhost
ExecStop=/usr/bin/vncserver -kill :%i

[Install]
WantedBy=default.target

Use the %h specifier for the user home directory. I have omitted the User= field, which doesn't make sense in user sessions. Also note the change to WantedBy in [Install] from multi-user.target (which does not exist in user sessions) to default.target.

The users can then control this service using systemctl --user commands. (Note that you might need to restart after enabling linger if that user hasn't logged in yet, so that a user session is started for them.)

Kartik
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muru
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