GRUBBY COMMAND 활용
grubby 라는 명령을 통해 GRUB2 부트로더를 손쉽게 수정 할 수 있습니다.
grubby –help
[root@fastvm-centos-7-6-21 ~]# grubby --help
Usage: grubby [OPTION...]
--add-kernel=kernel-path add an entry for the specified kernel
--add-multiboot=STRING add an entry for the specified multiboot
kernel
--args=args default arguments for the new kernel or
new arguments for kernel being updated
--mbargs=STRING default arguments for the new multiboot
kernel or new arguments for multiboot
kernel being updated
--bad-image-okay don`t sanity check images in boot
entries (for testing only)
--boot-filesystem=bootfs filesystem which contains /boot
directory (for testing only)
--bootloader-probe check which bootloader is installed on
boot sector
-c, --config-file=path path to grub config file to update ("-"
for stdin)
--copy-default use the default boot entry as a template
for the new entry being added; if the
default is not a linux image, or if the
kernel referenced by the default image
does not exist, the first linux entry
whose kernel does exist is used as the
template
--debug print debugging information for failures
--default-kernel display the path of the default kernel
--default-index display the index of the default kernel
--default-title display the title of the default kernel
--elilo configure elilo bootloader
--efi force grub2 stanzas to use efi
--env=path path for environment data
--extlinux configure extlinux bootloader (from
syslinux)
--grub configure grub bootloader
--grub2 configure grub2 bootloader
--info=kernel-path display boot information for specified
kernel
--initrd=initrd-path initrd image for the new kernel
-i, --extra-initrd=initrd-path auxiliary initrd image for things other
than the new kernel
--lilo configure lilo bootloader
--make-default make the newly added entry the default
boot entry
-o, --output-file=path path to output updated config file ("-"
for stdout)
--remove-args=STRING remove kernel arguments
--remove-mbargs=STRING remove multiboot kernel arguments
--remove-kernel=kernel-path remove all entries for the specified
kernel
--remove-multiboot=STRING remove all entries for the specified
multiboot kernel
--set-default=kernel-path make the first entry referencing the
specified kernel the default
--set-default-index=entry-index make the given entry index the default
entry
--set-index=entry-index use the given index when creating a new
entry
--silo configure silo bootloader
--title=entry-title title to use for the new kernel entry
--update-kernel=kernel-path updated information for the specified
kernel
-v, --version print the version of this program and
exit
--yaboot configure yaboot bootloader
--zipl configure zipl bootloader
Help options:
-?, --help Show this help message
--usage Display brief usage message
grubby 를 이용해서 현재 부트로더 설정 확인
# 파라미터 확인
[root@fastvm-centos-7-6-21 ~]# grubby --info=ALL
index=0
kernel=/boot/vmlinuz-3.10.0-957.el7.x86_64
args="ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8 LANG=en_US.UTF-8"
root=/dev/mapper/c7vg-root_lv
initrd=/boot/initramfs-3.10.0-957.el7.x86_64.img
title=CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)
index=1
kernel=/boot/vmlinuz-0-rescue-59c8a0b7323f456ab9d1194e09abca71
args="ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8"
root=/dev/mapper/c7vg-root_lv
initrd=/boot/initramfs-0-rescue-59c8a0b7323f456ab9d1194e09abca71.img
title=CentOS Linux (0-rescue-59c8a0b7323f456ab9d1194e09abca71) 7 (Core)
index=2
non linux entry
grubby 를 이용해서 부트로더에 파라미터 추가
# 파라미터 추가
[root@fastvm-centos-7-6-21 ~]# grubby --update-kernel=ALL --args="spectre_v2=off nopti"
# 추가된 내용 확인
[root@fastvm-centos-7-6-21 ~]# grubby --info=ALL
index=0
kernel=/boot/vmlinuz-3.10.0-957.el7.x86_64
args="ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8 LANG=en_US.UTF-8 spectre_v2=off nopti"
root=/dev/mapper/c7vg-root_lv
initrd=/boot/initramfs-3.10.0-957.el7.x86_64.img
title=CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)
index=1
kernel=/boot/vmlinuz-0-rescue-59c8a0b7323f456ab9d1194e09abca71
args="ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8 spectre_v2=off nopti"
root=/dev/mapper/c7vg-root_lv
initrd=/boot/initramfs-0-rescue-59c8a0b7323f456ab9d1194e09abca71.img
title=CentOS Linux (0-rescue-59c8a0b7323f456ab9d1194e09abca71) 7 (Core)
index=2
non linux entry
[root@fastvm-centos-7-6-21 ~]#
grubby 를 이용해서 부트로더의 파라미터 삭제
# 파라미터 제거
[root@fastvm-centos-7-6-21 ~]# grubby --update-kernel=ALL --remove-args="spectre_v2=off nopti"
# 제거된 내용 확인
[root@fastvm-centos-7-6-21 ~]# grubby --info=ALL
index=0
kernel=/boot/vmlinuz-3.10.0-957.el7.x86_64
args="ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8 LANG=en_US.UTF-8"
root=/dev/mapper/c7vg-root_lv
initrd=/boot/initramfs-3.10.0-957.el7.x86_64.img
title=CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)
index=1
kernel=/boot/vmlinuz-0-rescue-59c8a0b7323f456ab9d1194e09abca71
args="ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8"
root=/dev/mapper/c7vg-root_lv
initrd=/boot/initramfs-0-rescue-59c8a0b7323f456ab9d1194e09abca71.img
title=CentOS Linux (0-rescue-59c8a0b7323f456ab9d1194e09abca71) 7 (Core)
index=2
non linux entry
[root@fastvm-centos-7-6-21 ~]#
상기 --update-kernel= 에 특정 커널을 지정하여 특정 커널에만 부트로더 파라미터를 적용 할 수 있다.
cat /proc/cmdline
grubby 외에도 현재 부팅된 부트로더 파라미터를 확인 하는 방법이 있습니다.
확인 방법은 아래와 같습니다.
[root@fastvm-centos-7-6-21 ~]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/c7vg-root_lv ro crashkernel=128M rd.lvm.lv=c7vg/root_lv rd.lvm.lv=c7vg/swap_lv console=ttyS0,115200n8 LANG=en_US.UTF-8 spectre_v2=off nopti