CentOS7 Grub引导故障恢复全过程

grub> ls

grub> ls (hd0,1)/
grub> ls (hd0,2)/

# 设置根设备为/boot分区
grub> set root=(hd0,1)
# 加载Linux内核
grub> linux /vmlinuz-3.10.0-1160.el7.x86_64 ro root=/dev/mapper/centos-root
# 加载initramfs
grub> initrd /initramfs-3.10.0-1160.el7.x86_64.img
# 启动系统
grub> boot

# mount -o remount,rw /

grub2-mkconfig -o /boot/grub2/grub.cfg

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-1160.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-1160.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-xxxx
Found initrd image: /boot/initramfs-0-rescue-xxxx.img
done

# grub2-install /dev/sda

# ls -la /boot/grub2/grub.cfg
-rw-r--r--. 1 root root 6538 Dec  1 10:30 /boot/grub2/grub.cfg

# cat /boot/grub2/grub.cfg | grep menuentry

# 检查磁盘分区
# fdisk -l

# 挂载根分区
# mkdir /mnt/sysimage
# mount /dev/mapper/centos-root /mnt/sysimage

# 挂载boot分区（如果是单独分区）
# mount /dev/sda1 /mnt/sysimage/boot

# 挂载必要的文件系统
# mount --bind /dev /mnt/sysimage/dev
# mount --bind /proc /mnt/sysimage/proc
# mount --bind /sys /mnt/sysimage/sys

# 切换到原系统环境
# chroot /mnt/sysimage

# 重新生成GRUB配置
# grub2-mkconfig -o /boot/grub2/grub.cfg

# 重新安装GRUB
# grub2-install /dev/sda

# 退出chroot并重启
# exit
# reboot

# 备份GRUB配置
# cp /boot/grub2/grub.cfg /boot/grub2/grub.cfg.backup

# 定期检查系统完整性
# rpm -Va | grep grub2