Perché la mia unità utente systemd non si avvia all'avvio?

Sto cercando di creare un'unità utente systemd e farla avviare all'avvio del sistema. Il servizio si avvia manualmente, tuttavia non si avvia all'avvio.

Dalla ricerca in Internet ho appreso che per avviare le unità utente all'avvio, presumibilmente ho bisogno di funzionare loginctl enable-linger <username>, ma questo sembra non aver avuto alcun effetto. In effetti, la pagina man dice:

       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.

Nonostante esegua questo comando, il mio servizio non si avvia all'avvio.

loginctl enable-linger error

L'unità:

$ cat ~/.config/systemd/user/thin\@.service
[Unit]
Description=A fast and very simple Ruby web server

[Service]
Type=simple
EnvironmentFile=/home/error/.config/thin/%i
ExecStart=/usr/bin/bash /home/error/.rvm/wrappers/%i/thin start -a $THIN_BIND -p $THIN_PORT
WorkingDirectory=/srv/www/%i
PrivateTmp=true

[Install]
WantedBy=multi-user.target

Al riavvio, non è in esecuzione:

$ systemctl --user status thin@redmine -l
● thin@redmine.service - A fast and very simple Ruby web server
   Loaded: loaded (/home/error/.config/systemd/user/thin@.service; enabled; vendor preset: enabled)
   Active: inactive (dead)

# systemctl status user@1000 -l
● user@1000.service - User Manager for UID 1000
   Loaded: loaded (/usr/lib/systemd/system/user@.service; static; vendor preset: disabled)
   Active: active (running) since Wed 2015-12-23 19:43:27 GMT; 13s ago
 Main PID: 613 (systemd)
   Status: "Startup finished in 38ms."
   CGroup: /user.slice/user-1000.slice/user@1000.service
           ├─613 /usr/lib/systemd/systemd --user
           └─615 (sd-pam)                                                          

Dec 23 19:43:27 redmine systemd[613]: Reached target Sockets.
Dec 23 19:43:27 redmine systemd[613]: Starting Sockets.
Dec 23 19:43:27 redmine systemd[613]: Reached target Timers.
Dec 23 19:43:27 redmine systemd[613]: Starting Timers.
Dec 23 19:43:27 redmine systemd[613]: Reached target Basic System.
Dec 23 19:43:27 redmine systemd[613]: Starting Basic System.
Dec 23 19:43:27 redmine systemd[613]: Reached target Default.
Dec 23 19:43:27 redmine systemd[613]: Startup finished in 38ms.
Dec 23 19:43:27 redmine systemd[613]: Starting Default.
Dec 23 19:43:27 redmine systemd[1]: Started User Manager for UID 1000.

Posso avviarlo manualmente e funziona:

$ systemctl --user start thin@redmine
$ systemctl --user status thin@redmine -l
● thin@redmine.service - A fast and very simple Ruby web server
   Loaded: loaded (/home/error/.config/systemd/user/thin@.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2015-12-23 19:43:50 GMT; 5s ago
 Main PID: 1265 (ruby)
   CGroup: /user.slice/user-1000.slice/user@1000.service/thin.slice/thin@redmine.service
           └─1265 ruby /home/error/.rvm/gems/ruby-2.2.1@redmine/bin/thin start -a ::1 -p 8008

Dec 23 19:43:50 redmine systemd[613]: Started A fast and very simple Ruby web server.
Dec 23 19:43:50 redmine systemd[613]: Starting A fast and very simple Ruby web server...
Dec 23 19:43:52 redmine bash[1265]: /home/error/.rvm/gems/ruby-2.2.1@redmine/gems/htmlentities-4.3.1/lib/htmlentities/mappings/expanded.rb:465: warning: duplicated key at line 466 ignored: "inodot"

# systemctl status user@1000 -l
● user@1000.service - User Manager for UID 1000
   Loaded: loaded (/usr/lib/systemd/system/user@.service; static; vendor preset: disabled)
   Active: active (running) since Wed 2015-12-23 19:43:27 GMT; 40s ago
 Main PID: 613 (systemd)
   Status: "Startup finished in 38ms."
   CGroup: /user.slice/user-1000.slice/user@1000.service
           ├─613 /usr/lib/systemd/systemd --user
           ├─615 (sd-pam)                                                       
           └─thin.slice
             └─thin@redmine.service
               └─1265 ruby /home/error/.rvm/gems/ruby-2.2.1@redmine/bin/thin start -a ::1 -p 8008                                                               

Dec 23 19:43:27 redmine systemd[613]: Startup finished in 38ms.
Dec 23 19:43:27 redmine systemd[613]: Starting Default.
Dec 23 19:43:27 redmine systemd[1]: Started User Manager for UID 1000.
Dec 23 19:43:50 redmine systemd[613]: Created slice -.slice.
Dec 23 19:43:50 redmine systemd[613]: Starting -.slice.
Dec 23 19:43:50 redmine systemd[613]: Created slice thin.slice.
Dec 23 19:43:50 redmine systemd[613]: Starting thin.slice.
Dec 23 19:43:50 redmine systemd[613]: Started A fast and very simple Ruby web server.
Dec 23 19:43:50 redmine systemd[613]: Starting A fast and very simple Ruby web server...
Dec 23 19:43:52 redmine bash[1265]: /home/error/.rvm/gems/ruby-2.2.1@redmine/gems/htmlentities-4.3.1/lib/htmlentities/mappings/expanded.rb:465: warning: duplicated key at line 466 ignored: "inodot"

Come faccio a capire perché questo servizio non si avvia all'avvio e farlo funzionare?

Il sistema operativo è Fedora 23 x86_64, systemd 222-10.

Figure che avrei capito da solo.

L'indizio era qui, nell'output del servizio utente:

Dec 23 19:43:27 redmine systemd[613]: Reached target Default.

La mia unità stava chiedendo di essere caricata multi-user.target, ma non esiste tale destinazione nel sistema dell'utente.

Ho cambiato questo in default.targetnel file dell'unità, disabilitato e riattivato il servizio, e ora inizia all'avvio.

[Install]
WantedBy=default.target

e poi

$ systemctl --user disable thin@redmine
Removed symlink /home/error/.config/systemd/user/multi-user.target.wants/thin@redmine.service.
$ systemctl --user daemon-reload
$ systemctl --user enable thin@redmine
Created symlink from /home/error/.config/systemd/user/default.target.wants/thin@redmine.service to /home/error/.config/systemd/user/thin@.service.