To remove the default rescue image that gets installed when you install a CentOS/RHEL 7 system. To list out the rescue image under /boot directory :
[root@ucartz ~]# ls -lrt /boot total 135164 -rw-------. 1 root root 3113253 Oct 17 2018 System.map-3.10.0-514.el7.x86_64 -rw-r--r--. 1 root root 137696 Oct 17 2018 config-3.10.0-514.el7.x86_64 -rwxr-xr-x. 1 root root 5392080 Oct 17 2018 vmlinuz-3.10.0-514.el7.x86_64 -rw-r--r--. 1 root root 277953 Oct 17 2018 symvers-3.10.0-514.el7.x86_64.gz drwxr-xr-x. 2 root root 27 Oct 14 19:50 grub -rw-------. 1 root root 64487503 Oct 14 20:00 initramfs-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e.img -rwxr-xr-x. 1 root root 5392080 Oct 14 20:00 vmlinuz-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e -rw-r--r--. 1 root root 10209739 Oct 14 20:00 initrd-plymouth.img -rw-------. 1 root root 30753143 Oct 14 20:02 initramfs-3.10.0-514.el7.x86_64.img drwx------. 6 root root 111 Oct 14 20:02 grub2 -rw-------. 1 root root 18624164 Oct 14 22:10 initramfs-3.10.0-514.el7.x86_64kdump.img
You can not simply do arm on the rescue image in /boot directory. There are other entries such as in the menu entry in grub2 configuration file which needs to be removed as well. Follow the steps below to remove the default rescue image from the system.
Removing rescue image using grubby
1. Remove the rescue image from the /boot directory first.
rm -fr /boot/vmlinuz-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e
2. Locate the rescue menu entry in the GRUB2 configuration file /boot/grub2/grub.cfg which needs to be deleted.
# cat /boot/grub2/grub.cfg
....
menuentry 'CentOS Linux (0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e) 7 (Core)' --class centos --class gnu-linux --class
gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e-advanced-10bac86a-a9be-478c-b63f-46d3ca061e03' {
load_video
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 --hint='hd0,msdos1' a52207e4-01fd-4f12-98b7-681d56f21dc5
else
search --no-floppy --fs-uuid --set=root a52207e4-01fd-4f12-98b7-681d56f21dc5
fi
linux16 /vmlinuz-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e root=/dev/mapper/cl-root ro crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap rhgb quiet
initrd16 /initramfs-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e.img
}
....
3. Remove the rescue image using the grubby command with –remove-kernel option.
# grubby --remove-kernel=/boot/vmlinuz-0-rescue-9cdb9ab3246a4b3f9c0849ecd597f25e
4. Verify that the rescue image menu entry is now removed from the grub2 configuration file.
# cat /boot/grub2/grub.cfg | grep rescue
