The changes made in grub.cfg don't take effect after the hard powering off/on.

Issue

• The changes made in grub.cfg don't take effect after the hard powering off/on with ipmitool.

• Steps to reproduce

  • Delete the cmdline parameter, "intel_iommu=on" from GRUB_CMDLINE_LINUX line in /etc/default/grub

  # cat /etc/default/grub 
      ...
  GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet intel_iommu=on"
      ...
  
  # vim /etc/default/grub 
  
  # cat /etc/default/grub 
      ...
  GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet"
      ...
  

  • Rebuild grub.cfg with grub2-mkconfig and check that the change has been applied

  # grub2-mkconfig -o /boot/grub2/grub.cfg
  
  # cat /boot/grub2/grub.cfg | grep linux16
      linux16 /vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet 
      linux16 /vmlinuz-0-rescue-62d499ded71248fe9e0f179c4aaf4942 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet
  

  • Power off the server with ipmitool power off

  # ipmitool power off
  

  • Power on the server to boot into the kernel with the change being applied
  • After powering on, we can see that the change has been applied to grub.cfg but not applied to cmdline

  # cat /boot/grub2/grub.cfg | grep linux16
      linux16 /vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet 
      linux16 /vmlinuz-0-rescue-62d499ded71248fe9e0f179c4aaf4942 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet 
  
  # cat /proc/cmdline 
  BOOT_IMAGE=/vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet intel_iommu=on
  

  • However, after the subsequent reboot, we can see that the change has been applied to both grub.cfg and cmdline

  # systemctl reboot
  
  # cat /boot/grub2/grub.cfg | grep linux16
      linux16 /vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet 
      linux16 /vmlinuz-0-rescue-62d499ded71248fe9e0f179c4aaf4942 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet 
  
  # cat /proc/cmdline 
  BOOT_IMAGE=/vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/rhel00-root ro crashkernel=auto rd.lvm.lv=rhel00/root rd.lvm.lv=rhel00/swap rhgb quiet