3.2.1.1 Kernel Boot Parameters

The following table lists commonly-used kernel boot parameters.

Option	Description
`1\|2\|3\|4\|5`	Specifies the run level, overriding the value set in `/etc/inittab`.
`KEYBOARDTYPE=kbtype`	Specifies the keyboard type, which is written to `/etc/sysconfig/keyboard` in the `initramfs`.
`KEYTABLE=kbtype`	Specifies the keyboard layout, which is written to `/etc/sysconfig/keyboard` in the `initramfs`.
`LANG=language_territory.codeset`	Specifies the system language and code set, which is written to `/etc/sysconfig/i18n` in the `initramfs`.
`max_loop=N`	Specifies the number of loop devices (`/dev/loop`) that are available for accessing files as block devices. The default and maximum values of `N`* are 8 and 255.
`nouptrack`	Disables Ksplice Uptrack updates from being applied to the kernel.
`quiet`	Reduces debugging output.
`rd_LUKS_UUID=UUID`	Activates an encrypted Linux Unified Key Setup (LUKS) partition with the specified UUID.
`rd_LVM_VG=vg/lv_vol`	Specifies an LVM volume group and volume to be activated.
`rd_NO_LUKS`	Disables detection of an encrypted LUKS partition.
`rhgb`	Specifies that the Red Hat graphical boot display should be used to indicate the progress of booting.
`rn_NO_DM`	Disables Device-Mapper (DM) RAID detection.
`rn_NO_MD`	Disables Multiple Device (MD) RAID detection.
`ro root=/dev/mapper/vg-lv_root`	Specifies that the root file system is to be mounted read only, and specifies the root file system by the device path of its LVM volume (where `vg` is the name of the volume group).
`rw root=UUID=UUID`	Specifies that the root (`/`) file system is to be mounted read-writable at boot time, and specifies the root partition by its UUID.
`selinux=0`	Disables SELinux.
`single`	Boots the computer in single-user mode, without prompting for the `root` password.
`SYSFONT=font`	Specifies the console font, which is written to `/etc/sysconfig/i18n` in the `initramfs`.

The kernel boot parameters that were last used to boot a system are recorded in /proc/cmdline, for example:

# cat /proc/cmdline
ro root=/dev/mapper/VolGroup-lv_root rd_NO_LUKS KEYBOARDTYPE=pc KEYTABLE=us
LANG=en_US.UTF-8 rd_NO_MD rd_LVM_LV=VolGroup/lv_swap SYSFONT=latarcyrheb-sun16
rd_LVM_LV=VolGroup/lv_root rd_NO_DM rhgb quiet selinux=0