1. Go to centos recovery at boot time
2. List your partitions. In case of LVM run
root@localhost:~$ ls /dev/mapper
3. Mount Linux image:
root@localhost:~$ mkdir /mnt/root
root@localhost:~$ mount /dev/mapper/centos-root /mnt/root
4. bind system paths
root@localhost:~$ mount -o bind /dev /mnt/root/dev
root@localhost:~$ mount -o bind /sys /mnt/root/sys
root@localhost:~$ mount -o bind /proc /mnt/root/proc
root@localhost:~$ mount -o bind /proc /mnt/root/boot
4. Chroot and fix boot:
root@localhost:~$ chroot /mnt/root
root@localhost:~$ cd /boot
root@localhost:~$ dracut -f
root@localhost:~$ grub2-mkconfig -o /boot/grub2/grub.cfg
5. Exit And reboot:
root@localhost:~$ exit
root@localhost:~$ reboot