Systemd – Fix Per-User Instance Not Starting Service Unit Automatically

debiansystemd

I want the systemd per-user instance to start a following service unit at bootup:

user.name@svr:~$ systemctl --user cat tmux
# /etc/systemd/user/tmux.service
[Unit]
Description=Start tmux in detached session

[Service]
Type=forking
ExecStart=/usr/bin/tmux new-session -s test -d
ExecStop=/usr/bin/tmux kill-session -t test
Restart=always
RestartSec=1

[Install]
WantedBy=default.target
user.name@svr:~$

Lingering is enabled:

user.name@svr:~$ sudo loginctl show-user user.name | grep Linger=
Linger=yes
user.name@svr:~$

However, when I restart the server, then service is not started:

user.name@svr:~$ systemctl --user status tmux
● tmux.service - Start tmux in detached session
   Loaded: loaded (/etc/systemd/user/tmux.service; enabled; vendor preset: enabled)
   Active: inactive (dead)
user.name@svr:~$

I can start the tmux service manually with systemctl --user status tmux without any issues. Also, according to systemctl --user status the systemd per-user instance itself is running:

user.name@svr:~$ systemctl --user status 
● svr
    State: running
     Jobs: 0 queued
   Failed: 0 units
    Since: Tue 2019-12-03 22:02:41 UTC; 15min ago
   CGroup: /user.slice/user-1000.slice/user@1000.service
           └─init.scope
             ├─456 /lib/systemd/systemd --user
             └─462 (sd-pam)
user.name@svr:~$

This should mean that there are no issues with Linux PAM configuration.

Why doesn't systemd per-user instance start a service unit automatically?

Best Answer

I enabled(systemctl --user enable tmux) the tmux.service at the time when I had WantedBy=multi-user.target in the [Install] section of the /etc/systemd/user/tmux.service and later forgot to re-enable the service. Checking the content of the ~/.config/systemd/user/ directory helped me to spot my mistake.

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Why x0vncserver is not starting at boot

As x0vncserver will only start after xsession, and as mine is an LXDE environment, the easier way is to create a script.sh file like following

#!/bin/bash
x0vncserver -display :0 -rfbport 5900 -passwordfile ~/.vnc/passwd

and make it executable by sudo chmod +x script.sh and add a line in ~/.config/lxsession/LXDE/autostart file like following

path_to_the_script_file/script.sh

and the x0vncserver starts as my LXDE desktop session starts and that's what I need.

Why is systemd stopping service immediately after it is started

Environment="USER=ubuntu" "Path=/home/ubuntu/console/bin" 
WorkingDirectory=/home/ubuntu/console/bin
ExecStart=/bin/sh -ec "exec /sbin/start-stop-daemon -S -c ${USER} -d ${Path} --pidfile=/var/run/console.pid --oknodo  --exec consoleExecutable " #2>/dev/null
ExecStop=/bin/sh -ec "exec /sbin/start-stop-daemon -K --quiet -c ${USER} -d ${Path} --pidfile=/var/run/console.pid  --retry=TERM/30/KILL/5 --oknodo --exec consoleExecutable" #2>/dev/null

This is almost worthy of the systemd House of Horror. Were it not the case that there's a horror story already in there that does this.

Do not use start-stop-daemon in a service unit to do all of the things that a service unit already does. With unnecessary PID files and the wrongheaded assumption that ExecStart accepts shell syntax comments, no less.

And do not do what the other answer says and try to bodge it with Type=forking. That makes things worse, not better.

The nonsense with start-stop-daemon is why things are going wrong. Because the process running start-stop-daemon does not become the service, but in fact exits pretty much imediately, systemd is thinking that your service is terminating. In your first systemctl status output, you can see that systemd is in the middle of sending SIGTERM to clean up all left-over running processes after running the ExecStop action, which is what it does when it thinks that a service has terminated.

Just do things simply:

Type=simple
WorkingDirectory=/home/ubuntu/console/bin
User=ubuntu
ExecStart=/home/ubuntu/console/bin/consoleExecutable

No ExecStop nor Environment is actually required.

Best Answer

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Further reading

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