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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
    



2015-04-13