CentOS 7
查看所有 menuentry
# cat /boot/grub2/grub.cfg | grep menuentry
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
menuentry_id_option=""
export menuentry_id_option
menuentry 'CentOS Linux (4.4.34-1.el7.elrepo.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-3d336981-24de-4456-87af-9094e7cdb25c' {
menuentry 'CentOS Linux (3.10.0-327.36.3.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-3d336981-24de-4456-87af-9094e7cdb25c' {
menuentry 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-3d336981-24de-4456-87af-9094e7cdb25c' {
menuentry 'CentOS Linux (0-rescue-66f00fb9b7b84667bc1f1aa321d6569b) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-66f00fb9b7b84667bc1f1aa321d6569b-advanced-3d336981-24de-4456-87af-9094e7cdb25c' {
查看当前默认选项
# grub2-editenv list
saved_entry=CentOS Linux (3.10.0-327.36.3.el7.x86_64) 7 (Core)
更改默认启动选项
grub2-set-default "CentOS Linux (4.4.34-1.el7.elrepo.x86_64) 7 (Core)"
CentOS 8
使用 grubby 配置，一般都默认安装
dnf install grubby
查看默认启动项
grubby --default-kernel
/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64
查看所有内核
grubby --info=ALL
index=0
kernel="/boot/vmlinuz-4.18.0-80.11.2.el8_0.x86_64"
args="ro crashkernel=auto resume=UUID=b9b14ba1-0b5c-49ac-842f-f11fa2081cfd console=ttyS0 $tuned_params"
root="UUID=3db5c437-b4f7-46cf-a20e-0345459003f3"
initrd="/boot/initramfs-4.18.0-80.11.2.el8_0.x86_64.img $tuned_initrd"
title="CentOS Linux (4.18.0-80.11.2.el8_0.x86_64) 8 (Core)"
id="f56bd0e5ce8b45e594c3fb6d1753d61d-4.18.0-80.11.2.el8_0.x86_64"
index=1
kernel="/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64"
args="ro crashkernel=auto resume=UUID=b9b14ba1-0b5c-49ac-842f-f11fa2081cfd console=ttyS0 $tuned_params"
root="UUID=3db5c437-b4f7-46cf-a20e-0345459003f3"
initrd="/boot/initramfs-4.18.0-80.7.1.el8_0.x86_64.img $tuned_initrd"
title="CentOS Linux (4.18.0-80.7.1.el8_0.x86_64) 8 (Core)"
id="f56bd0e5ce8b45e594c3fb6d1753d61d-4.18.0-80.7.1.el8_0.x86_64"
index=2
kernel="/boot/vmlinuz-4.18.0-80.el8.x86_64"
args="ro crashkernel=auto resume=UUID=b9b14ba1-0b5c-49ac-842f-f11fa2081cfd console=ttyS0 $tuned_params"
root="UUID=3db5c437-b4f7-46cf-a20e-0345459003f3"
initrd="/boot/initramfs-4.18.0-80.el8.x86_64.img $tuned_initrd"
title="CentOS Linux (4.18.0-80.el8.x86_64) 8 (Core)"
id="f56bd0e5ce8b45e594c3fb6d1753d61d-4.18.0-80.el8.x86_64"
index=3
kernel="/boot/vmlinuz-0-rescue-f56bd0e5ce8b45e594c3fb6d1753d61d"
args="ro crashkernel=auto resume=UUID=b9b14ba1-0b5c-49ac-842f-f11fa2081cfd console=ttyS0"
root="UUID=3db5c437-b4f7-46cf-a20e-0345459003f3"
initrd="/boot/initramfs-0-rescue-f56bd0e5ce8b45e594c3fb6d1753d61d.img"
title="CentOS Linux (0-rescue-f56bd0e5ce8b45e594c3fb6d1753d61d) 8 (Core)"
id="f56bd0e5ce8b45e594c3fb6d1753d61d-0-rescue"
查看指定内核启动项
grubby --info=/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64
index=1
kernel="/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64"
args="ro crashkernel=auto resume=UUID=b9b14ba1-0b5c-49ac-842f-f11fa2081cfd console=ttyS0 $tuned_params"
root="UUID=3db5c437-b4f7-46cf-a20e-0345459003f3"
initrd="/boot/initramfs-4.18.0-80.7.1.el8_0.x86_64.img $tuned_initrd"
title="CentOS Linux (4.18.0-80.7.1.el8_0.x86_64) 8 (Core)"
id="f56bd0e5ce8b45e594c3fb6d1753d61d-4.18.0-80.7.1.el8_0.x86_64"
修改默认启动
grubby --set-default /boot/vmlinuz-4.18.0-80.11.2.el8_0.x86_64
The default is /boot/loader/entries/f56bd0e5ce8b45e594c3fb6d1753d61d-4.18.0-80.11.2.el8_0.x86_64.conf with index 0 and kernel /boot/vmlinuz-4.18.0-80.11.2.el8_0.x86_64
[root@aikaiyuan ~]# grubby --default-kernel
/boot/vmlinuz-4.18.0-80.11.2.el8_0.x86_64
修改内核启动项参数
grubby --update-kernel=/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64 --args=console=ttyS0,115200
grubby --info=/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64
index=1
kernel="/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64"
args="ro crashkernel=auto resume=UUID=b9b14ba1-0b5c-49ac-842f-f11fa2081cfd $tuned_params console=ttyS0,115200"
root="UUID=3db5c437-b4f7-46cf-a20e-0345459003f3"
initrd="/boot/initramfs-4.18.0-80.7.1.el8_0.x86_64.img $tuned_initrd"
title="CentOS Linux (4.18.0-80.7.1.el8_0.x86_64) 8 (Core)"
id="f56bd0e5ce8b45e594c3fb6d1753d61d-4.18.0-80.7.1.el8_0.x86_64"
–update-kernel=/boot/vmlinuz-4.18.0-80.7.1.el8_0.x86_64
–update-kernel=ALL 也可以更新 所有内核
console=ttyS0,115200
