Come verificare il target attivo corrente in RHEL7 / CentOS 7

In RHEL 6 possiamo eseguire runlevelper controllare il runlevel corrente del mio sistema.

In RHEL 7 abbiamo il comando systemctl get-defaultper verificare la destinazione predefinita ma come verificare la destinazione attiva corrente?

systemctl list-units --type target

Come da documentazione qui: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sect-Managing_Services_with_systemd-Targets.html

Ecco l'output di esempio (non viene fornita una risposta di una riga):

[root@ ~]# systemctl list-units --type target
UNIT                   LOAD   ACTIVE SUB    DESCRIPTION
basic.target           loaded active active Basic System
cryptsetup.target      loaded active active Encrypted Volumes
getty.target           loaded active active Login Prompts
graphical.target       loaded active active Graphical Interface
local-fs-pre.target    loaded active active Local File Systems (Pre)
local-fs.target        loaded active active Local File Systems
multi-user.target      loaded active active Multi-User System
network-online.target  loaded active active Network is Online
network.target         loaded active active Network
nfs-client.target      loaded active active NFS client services
nss-user-lookup.target loaded active active User and Group Name Lookups
paths.target           loaded active active Paths
remote-fs-pre.target   loaded active active Remote File Systems (Pre)
remote-fs.target       loaded active active Remote File Systems
slices.target          loaded active active Slices
sockets.target         loaded active active Sockets
sound.target           loaded active active Sound Card
swap.target            loaded active active Swap
sysinit.target         loaded active active System Initialization
timers.target          loaded active active Timers

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

20 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
[root@ ~]# systemctl isolate multi-user.target
[root@ ~]# systemctl list-units --type target
UNIT                  LOAD   ACTIVE SUB    DESCRIPTION
basic.target          loaded active active Basic System
cryptsetup.target     loaded active active Encrypted Volumes
getty.target          loaded active active Login Prompts
local-fs-pre.target   loaded active active Local File Systems (Pre)
local-fs.target       loaded active active Local File Systems
multi-user.target     loaded active active Multi-User System
network-online.target loaded active active Network is Online
network.target        loaded active active Network
nfs-client.target     loaded active active NFS client services
paths.target          loaded active active Paths
remote-fs-pre.target  loaded active active Remote File Systems (Pre)
remote-fs.target      loaded active active Remote File Systems
slices.target         loaded active active Slices
sockets.target        loaded active active Sockets
swap.target           loaded active active Swap
sysinit.target        loaded active active System Initialization
timers.target         loaded active active Timers

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

17 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
[root@ ~]# cat /etc/redhat-release 
CentOS Linux release 7.3.1611 (Core) 
[root@ ~]# 

Iniziamo con graphical.target e la prima volta che viene eseguito il comando, possiamo vedere sia multi-user.target che graphical.target. Questo perché graphical.target richiede multi-user.target.

Successivamente passiamo a multi-user.target. Se vedi multi-user.target ma non vedi graphical.target, allora siamo nella destinazione multiutente.

Gli altri due obiettivi comuni sono rescue.target e emergency.target.

• Se vedi rescue.target, allora sei nella destinazione di salvataggio.
• Se vedi emergency.target, allora sei nel target di emergenza.