Run Levels in RHEL7

Systemd has replaced sysVinit as the default service manager in RHEL7. Some of the sysVinit commands have been symlinked to their RHEL7 counterparts. However this will eventually be deprecated in favor of the standard commands in the feature.

SysVinit V/s systemd runlevels:

Here is a comparison between SysVinit runlevels V/s systemd targets.

SysVinit/Runlevel	Systemd Target	Function
0	Runlevel0.target, poweroff.target	System Halt/Shutdown
1,s,Single	Runlevel1.target, rescue.target	Single-user mode
2,4	Runlevel2.target, runlevel4.target, multi-user.target	User Defined/Site-Specific runlevels. By default, identical to 3.
3	Runlevel3.target, multi-user.target	Multi-User, Non-graphical mode, text console only
5	Runlevel5.target, graphical.target	Multi-user, graphicalmode
6	Runlevel6.target, reboot.target	Reboot
Emergency	Emergency.target	Emergency mode

Changing runlevels with systemd:

The runlevel target can be changed by using the systemctl isolate command:

# systemctl isolate multi-user.target

To view what targets are available you can issue the list-units option with the type target.

# systemctl list-units --type=target

Run level 3 is  emulated by multi-user.target. This is done by symbolic link and can be used interchangeably.

# systemctl isolate multi-user.target # systemctl isolate runlevel3.target # ls -l /usr/lib/systemd/system/runlevel3.target lrwxrwxrwx 1 root root 17 Oct 18 11:41 /usr/lib/systemd/system/runlevel3.target -> multi-user.target

Run level 5 is emulated by graphical.target. This is also done by symbolic link and can be used interchangeably.

# systemctl isolate graphical.target # systemctl isolate runlevel5.target # ls -l /usr/lib/systemd/system/runlevel5.target lrwxrwxrwx 1 root root 16 Oct 18 11:41 /usr/lib/systemd/system/runlevel5.target -> graphical.target

Changing the default runlevel:

The default runlevel can be changed by using the set-default option.

To get the currently set default, you can use the get-default option.

The default runlevel in systemd can also be set using the below method ( not recommended though).

The default target can also be set in the kernel line during boot by adding the following option: