CloudLinux OS 8 Not Booting Latest Kernel? Quick GRUB2 / BLS Fix

Problem (Symptom)

On CloudLinux OS 8 / CentOS 8:

• Server doesn’t boot into the CloudLinux kernel after reboot.
• Setting a default kernel with grub2-set-default has no effect.
• awk -F\' '$1=="menuentry "…' /etc/grub2.cfg shows limited or unexpected entries.

Cause

RHEL 8–based systems (including CloudLinux 8 and CentOS 8) use Boot Loader Specification (BLS) for kernel management. If GRUB2 is outdated or BLS is not enabled/configured correctly, the system may ignore your default kernel and fail to boot the latest CloudLinux kernel.

Quick Fix Steps

1. Update GRUB2 packages

Bashyum update grub2*

2. Enable saved default + BLS

Edit /etc/default/grub:

Bashnano /etc/default/grub

Ensure these lines exist:

iniGRUB_DEFAULT=saved
GRUB_ENABLE_BLSCFG=true

Save and exit.

3. Regenerate GRUB configs

Run the commands that match existing paths on your system (some may not exist; that’s fine):

Bashgrub2-mkconfig -o /etc/grub2.cfg
grub2-mkconfig -o /etc/grub2-efi.cfg
grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg
grub2-mkconfig -o /boot/efi/EFI/almalinux/grub.cfg

4. (Optional) Set CloudLinux kernel as default with grubby

List kernels:

Bashgrubby --info=ALL | grep ^kernel

Set the CloudLinux kernel:

Bashgrubby --set-default /boot/vmlinuz-<cloudlinux-kernel-version>

Check default:

Bashgrubby --default-kernel

5. Reboot and confirm

Bashreboot

After reboot:

Bashuname -r

You should now see the CloudLinux kernel as the running kernel.