Specifying Kernel Boot Parameters

1. Kernel command line
   

   [root@kvm4 ~]# cat /proc/cmdline 
   ro root=/dev/mapper/vg_kvmusb-root rd_LVM_LV=vg_kvmusb/root rd_LVM_LV=vg_kvmusb/swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us
   

2. bootparam man pages
   

   [root@kvm4 ~]# man 7 bootparam  # 7 Miscellanea
   .... 
   ’panic=N’
                 By  default  the  kernel will not reboot after a panic, but this
                 option will cause a kernel reboot  after  N  seconds  (if  N  is
                 greater than zero).  This panic timeout can also be set by "echo
                 N > /proc/sys/kernel/panic".
   ....
   

3. Change the default behavior th the kernel comman line
   

   [root@kvm4 ~]# vi /boot/grub/menu.lst 
   ....
   title KVM CentOS (2.6.32-71.el6.x86_64)
           root (hd0,0)
           kernel /vmlinuz-2.6.32-71.el6.x86_64 ro root=/dev/mapper/vg_kvmusb-root rd_LVM_LV=vg_kvmusb/root rd_LVM_LV=vg_kvmusb/swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto panic=30
   ...
   

4. Show the effects of the changes
   

   [root@kvm4 ~]# reboot
   
   [root@kvm4 ~]# cat /proc/cmdline
   ro root=/dev/mapper/vg_kvmusb-root rd_LVM_LV=vg_kvmusb/root rd_LVM_LV=vg_kvmusb/swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto panic=30