Changing Kernel on Next Boot

To choose which kernel version you want to boot into on next reboot, below are the steps

1. Check what kernel version is available

# grep ^menuentry /etc/grub.cfg

2. Choose which kernel that you want to boot from, remember that the list from the above command start from 0. Let's say we want to choose the second kernel

# grub2-set-default 1

3. Rebuild grub.cfg

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

4. Reboot the server

# reboot 

You server will reboot to the kernel version that you choose above.