Oracle Cloud Infrastructure Documentation

Systemd Targets

Describes how systemd targets map to run levels and how to inspect or change the system state.

By using targets, you can control systemd so that it starts only the services that are required for a specific purpose.

For example, you set the default target to multi-user.target on a production server so that the graphical user interface isn't used when the system boots. In a case where you need to troubleshoot or perform diagnostics, you might consider setting the target to rescue.target, where only root logs onto the system to run the minimum number of services.

Each run level defines the services that systemd stops or starts. As an example, systemd starts network services for multi-user.target and the X Window System for graphical.target, and stops both services for rescue.target.

System-State Targets and Equivalent Runlevel Targets shows the commonly used system-state targets and the equivalent runlevel targets.

System-State Targets and Equivalent Runlevel Targets

System-State Targets

Equivalent Runlevel Targets

Description

graphical.target

runlevel5.target

Set up a multiuser system with networking and display manager.

multi-user.target

runlevel2.target

runlevel3.target

runlevel4.target

Set up a nongraphical multiuser system with networking.

poweroff.target

runlevel0.target

Shut down and power off the system.

reboot.target

runlevel6.target

Shut down and reboot the system.

rescue.target

runlevel1.target

Set up a rescue shell.

Note that runlevel* targets are implemented as symbolic links.

For more information, see the systemd.target(5) manual page.

Displaying Default and Active System-State Targets

Shows how to query the system’s default target and list all active targets with systemctl.

To display the default system-state target, use the systemctl get-default command: 

systemctl get-default
graphical.target

To display the active targets on a system, use the systemctl list-units --type target command: 

systemctl list-units --type target [--all]
UNIT                   LOAD   ACTIVE SUB    DESCRIPTION                
basic.target           loaded active active Basic System               
cryptsetup.target      loaded active active Local 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-pre.target     loaded active active Network (Pre)              
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        
rpc_pipefs.target      loaded active active rpc_pipefs.target          
rpcbind.target         loaded active active RPC Port Mapper            
slices.target          loaded active active Slices                     
sockets.target         loaded active active Sockets                    
sound.target           loaded active active Sound Card                 
sshd-keygen.target     loaded active active sshd-keygen.target         
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.

24 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

The output for a system with the graphical target active shows that this target depends on other active targets, including network and sound for networking and sound functionality.

Use the --all option to include inactive targets in the list.

For more information, see the systemctl(1) and systemd.target(5) manual pages.

Changing Default and Active System-State Targets

Explains how to switch the default boot target and isolate a different target while the system is running.

Use the systemctl set-default command to change the default system-state target: 

sudo systemctl set-default multi-user.target
Removed /etc/systemd/system/default.target. 
Created symlink /etc/systemd/system/default.target → /usr/lib/systemd/system/multi-user.target
Note

This command changes the target to which the default target is linked, but doesn't change the state of the system.

To change the current active system target, use the systemctl isolate command, for example: 

sudo systemctl isolate multi-user.target

For more information, see the systemctl(1) manual page.