Andy

Administrator
#1
Prefer to see what’s actually happening in the background when your CentOS Linux is booting up?

Edit /etc/default/grub with your favourite editor, such as nano or vi.

[andy@av ~]# cat /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos_ba-eraappl-v/root rd.lvm.lv=centos_ba-eraappl-v/swap rhgbquiet net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
[andy@av ~]#

Basically we want to remove both rhgb and quiet above.

If you are curious what are them:
  • rhgb is the red hat graphical boot – This is a GUI mode
    booting screen with most of the information hidden while the user sees a
    rotating activity icon spinning and brief information as to what the
    computer is doing.
  • quiet hides the majority of boot messages before rhgb
    starts. These are supposed to make the common user more comfortable.
    They get alarmed about seeing the kernel and initialising messages, so
    they hide them for their comfort.
I personally prefer a faster bootloader wait time, hence I lowered my GRUB_TIMEOUT from 5 seconds to 1 seconds.

This is my /etc/default/grub output after I removed both rhgb and quiet option:

[andy@av ~]# cat /etc/default/grub
GRUB_TIMEOUT=1
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos_ba-eraappl-v/root rd.lvm.lv=centos_ba-eraappl-v/swap net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
[andy@av ~]#

After removed rhgb and quiet option, we need to update our grub2 boot configuration file by issuing this command:

[andy@av ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-862.14.4.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.14.4.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-514.2.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-514.2.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-327.36.3.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-327.36.3.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-06d71e1cb34f47898c320b96609134c6
Found initrd image: /boot/initramfs-0-rescue-06d71e1cb34f47898c320b96609134c6.img
done
[andy@av ~]#

Restart your system and you will notice that your system is now booting faster as well as you will be able to see all the boot processes in detailed ?
 
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