Traceback example: After update, kernel panic at boot with error: Unable to mount root fs on unknown-block(0,0)

Solution:
  1. Restart your server and on the boot screen select any other boot option with older kernel
  2. (optional, Leaseweb servers) Install missing dependency
sudo dnf install dracut-network
  1. Navigate to /boot and verify that initramfs-file doesn’t exist for the latest kernel version
  2. Generate it
# 4.18.0-338.el8.x86_64 is kernel version
dracut -f /boot/initramfs-4.18.0-338.el8.x86_64.img 4.18.0-338.el8.x86_64
  1. Regenerate grub files
grub2-mkconfig -o /boot/grub2/grub.cfg
  1. Restart
Sources: