Changing centos/redhat run level init 3

What is a runlevel ?

Runlevel is the preset state in which a Linux system operates. Below mentioned are the different runlevels of a Linux system in which a linux system can be operated

  • 0-  halt or shutdown
  • 1- single user mode
  • 2- multi user mode without NFS
  • 3- full multi-user mode
  • 4- not used
  • 5- graphical mode
  • 6- reboot

Change run level in centos 6

Method 1 – Change the run level at startup

Under Red Hat Enterprise Linux, it is possible to change the default runlevel at boot time.

To change the runlevel of a single boot session, use the following instructions:

  • When the GRUB menu bypass screen appears at boot time, press any key to enter the GRUB menu (within the first three seconds).
  • Press the a key to append to the kernel command.
  • Add <space><runlevel> at the end of the boot options line to boot to the desired runlevel. For example, the following entry would initiate a boot process into runlevel 3:
    grub append> ro root=/dev/VolGroup00/LogVol00 rhgb quiet 3

Method 2 – Change the run level on Started Server/Desktop

Changing default runlevel in Centos/RHEL 6 is very easy task & requires a change in single file.

  • Firstly, open file /etc/inittab
  • vim /etc/inittab
  • and you will get something like id:5:initdefault: in the file, where 5 is the default runlevel.
  • You must change 5 to desired runlevel, which in this case is 3 (multi-user mode).
  • After making changes to file, save it to change the default runlevel on boot.
  • This will implement after reboot the machine.


Change run level in centos 7

In CentOS 7 / RHEL 7,  systemd uses “targets” instead of run-levels.  /etc/inittab is no more used by systemd to change the run levels.

Change default to runlevel 3 (nothing but a

# systemctl set-default

Confirm the default runlevel.

# systemctl get-default

Reboot and check it out.

# reboot


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