grub> primer

Today I attempted a leapp upgrade of a CentOS 7 Virtualmin box to AlmaLinux 8. This failed and I saw the grub> menu.

Instead of panicking I decided to delve deeper with Grub. Through  the magic of ChatGPT I don’t have to sit through the Google search spam and I quickly found commands to make me boot the server. In a nutshell:

ls

(hd0) (hd0,msdos1)

ls (hd0,1)/

ls (hd0,1)/boot/grub2/grub.cfg

cat (hd0,1)/boot/grub2/grub.cfg

When I did cat I could see the file is empty.

configfile (hd0,1)/boot/grub2/grub.cfg.rmpsave

This booted the computer!

The running leapp I got this:

Message: Failed to call `grubby` to list available boot entries

As usual Redhat goes and blocks you from your work:

https://access.redhat.com/solutions/7001662

But this got me further:

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

After that and running leapp upgrade again, we get this:

Upgrade has been inhibited due to the following problems:
1. Leapp detected loaded kernel drivers which have been removed in RHEL 8. Upgrade cannot proceed.
2. Newest installed kernel not in use
3. Btrfs has been removed from RHEL8

Again, we remove floppy and pata_acpi. Next we deal with installed Kernel not in use.

Let’s reboot.

Rebooting takes us back to square one. After the first leapp upgrade, we got this error:

random: crng init done

random: 7 urandom warning(s) missed due to ratelimiting

More Redhat nonsense: behind a firewall:

https://access.redhat.com/solutions/5019311

After 20 seconds the first error appeared, after 140 seconds another one:

systemd[1060]: emergency.service: Failed to set up standard input: Inappropriate ioctl for device

 

Next we go big:

rmmod floppy

Warning, dracut is hardcore.

sudo dracut -f -v

Apparently this redoes initramfs

 

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