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status indireto da unidade systemd

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status indireto da unidade systemd

Gostaria de saber como posso verificar qual unidade ativa outra com status indireto?

Eu executo o Arch com Gnome e um servidor Debian. Na minha máquina Debian posso ver a saída dos systemctl list-unit-files --type=target --state=enabledshows, conforme esperado:

default.target    enabled
multi-user.target enabled

Mas no desktop Arch, surpreendentemente para mim, isso não acontece, embora ambos: multi-user.targete graphical.target(meu padrão no Arch) estejam ativos. Quando verifico o status desses arquivos de unidades, ambos são: indirect. Quando listo as dependências, graphical.targetele mostra gdm.servicee multi-user.target. No arquivo de unidade gdm não vejo Also=na [Install]seção. Então, o que exatamente ativa graphical.target?

Qual é a razão desta solução “indireta”?

Responder1

De man systemd.special:

gráfico.target 
       A special target unit for setting up a graphical login screen.
       This pulls in multi-user.target.

       Units that are needed for graphical logins shall add Wants= dependencies for their unit to this unit (or multi-user.target) during installation.
       This is best configured via WantedBy=graphical.target in the unit's [Install] section.

Então o conteúdo do seu gdm.serviceexplicaria mais as coisas ...

Abaixo estão as informações desses dois serviços no meu sistema, observe que eles são "estáticos"...

$ systemctl status multi-user.target graphical.target

● multi-user.target - Multi-User System
     Loaded: loaded (/lib/systemd/system/multi-user.target; static)
     Active: active since Mon 2023-09-04 09:34:27 +03; 11h ago
      Until: Mon 2023-09-04 09:34:27 +03; 11h ago
       Docs: man:systemd.special(7)

Sep 04 09:34:27 kubuntu systemd[1]: Reached target multi-user.target - Multi-User System.

● graphical.target - Graphical Interface
     Loaded: loaded (/lib/systemd/system/graphical.target; static)
     Active: active since Mon 2023-09-04 09:34:27 +03; 11h ago
      Until: Mon 2023-09-04 09:34:27 +03; 11h ago
       Docs: man:systemd.special(7)

Sep 04 09:34:27 kubuntu systemd[1]: Reached target graphical.target - Graphical Interface.

$ systemctl cat multi-user.target graphical.target

# /lib/systemd/system/multi-user.target
#  SPDX-License-Identifier: LGPL-2.1-or-later
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=Multi-User System
Documentation=man:systemd.special(7)
Requires=basic.target
Conflicts=rescue.service rescue.target
After=basic.target rescue.service rescue.target
AllowIsolate=yes

# /lib/systemd/system/graphical.target
#  SPDX-License-Identifier: LGPL-2.1-or-later
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=Graphical Interface
Documentation=man:systemd.special(7)
Requires=multi-user.target
Wants=display-manager.service
Conflicts=rescue.service rescue.target
After=multi-user.target rescue.service rescue.target display-manager.service
AllowIsolate=yes

$ ls -la /lib/systemd/system/{multi-user,graphical}.target
-rw-r--r-- 1 root root 606 Jan 26  2023 /lib/systemd/system/graphical.target
-rw-r--r-- 1 root root 540 Jan 26  2023 /lib/systemd/system/multi-user.target

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