[SOLVED] How can I delete the last Kernel from CentOS 8

Hanisch · 02-07-2022, 02:13 PM

Hello,
my last Kernel kernel-4.18.0-358.el8.x86_64 does not work in my VirtualBox-Installation.
I have now:

Quote:

$ sudo grubby --default-kernel
/boot/vmlinuz-4.18.0-348.7.1.el8_5.x86_64

Quote:

$ sudo rpm -q kernel
kernel-4.18.0-240.15.1.el8_3.x86_64
kernel-4.18.0-348.7.1.el8_5.x86_64
kernel-4.18.0-358.el8.x86_64

I should like delete the newest Kernel kernel-4.18.0-358.el8.x86_64

In the link https://www.thegeekdiary.com/how-to-...centos-rhel-8/
is show only the Deletion of older Kernels.

How can I Delete the newest Kernel?

With regards
Ch. Hanisch

wpeckham · 02-07-2022, 02:25 PM

Use the commands in that document to boot to find the kernel indexes, boot to an older kernel, and then make that older kernel your default and remove the newer kernel.

After that you will have to freeze your kernel so it will not update, or take other steps to protect yourself form updates changing the kernel.

shruggy · 02-07-2022, 02:55 PM

To list all installed kernel with their indices:

Code:

$ sudo grubby --info=ALL|egrep '^(index|kernel)='
index=0
kernel="/boot/vmlinuz-4.18.0-358.el8.x86_64"
index=1
kernel="/boot/vmlinuz-4.18.0-348.7.1.el8_5.x86_64"
index=2
kernel="/boot/vmlinuz-0-rescue-99f959ba76a9461d95f94cfb1d76f253"

Hanisch · 02-08-2022, 08:25 AM

Hello,
Sorry, I can't remove the newest Kernel from Boot-Menu.

Quote:

$ sudo yum remove kernel-4.18.0-358.el8.x86_64
Keine Übereinstimmung für Argumente: kernel-4.18.0-358.el8.x86_64
Keine Pakete zum Entfernen markiert.
Abhängigkeiten sind aufgelöst.
Nichts zu tun.
Fertig.

Quote:

$ sudo grub2-mkconfig -o /boot/grub2/grub.cfg
GRUB-Konfigurationsdatei wird erstellt …
Hintergrund gefunden: /usr/share/backgrounds/default-mit-Text.tga
erledigt

Quote:

$ sudo rpm -q kernel
kernel-4.18.0-240.15.1.el8_3.x86_64
kernel-4.18.0-348.7.1.el8_5.x86_64

The newest Kernel is always on Top in the Boot-Menu, but it has no function.

with regards
Ch. Hanisch

wpeckham · 02-08-2022, 11:12 AM

do not try to remove it form the grub menu, just change index 0 to the other kernel.
Then reboot and load tha other kernel so that you are not trying to remove the current kernel.
Then remove the kernel that is the problem.
To get the install name, you might have to list installed packages and see if the package name differs from what you expect.

I could probably make this more clear, if only I could read and write German.

Hanisch · 02-09-2022, 04:09 AM

Hello,
why delete the command:

Quote:

sudo yum remove kernel-4.18.0-358.el8.x86_64

this kernel not?

with regards
Ch. Hanisch

shruggy · 02-09-2022, 04:31 AM

What message do you get when trying to remove it?

Code:

No match for argument: kernel-4.18.0-358.el8.x86_64 
No packages marked for removal.

Then that kernel is not installed.

Update. Ah sorry. In your case, the exact messages could be

Code:

Keine Übereinstimmung für Argumente: kernel-4.18.0-358.el8.x86_64
Keine Pakete zum Entfernen markiert.

pan64 · 02-09-2022, 07:53 AM

you do not need to remove it at all, just set the previous one as default. And probably that's all.
The message means there is no such package at all, that is not the name of the package you are looking for. And anyway the next yum update will bring it back.

Hanisch · 02-10-2022, 04:27 AM

Quote:

... And anyway the next yum update will bring it back.

No, I have set:

Quote:

# cat /etc/yum.conf
[main]
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=True
best=True
skip_if_unavailable=False
exclude=kernel*

My problem is, that after manual deleting all /boot/*-4.18.0-358.* the Kernel 4.18.0-358.7.1.el8_5.x86_64 stands always at the top of my Boot-menu.
Where is that written in the system?

with regards
Ch. Hanisch

pan64 · 02-10-2022, 04:33 AM

I guess that is the grub config. Try to reconfigure it and run update-grub.

Hanisch · 02-10-2022, 09:42 AM

Quote:

Originally Posted by pan64

I guess that is the grub config. Try to reconfigure it and run update-grub.

How can I reconfigure grub config?
What mean you with grub config?

with regards
Ch. Hanisch

pan64 · 02-10-2022, 09:53 AM

grub is the boot loader. This is the tool which will show that boot menu. You need to [re]configure it to forget the deleted kernel.
https://www.howtogeek.com/196655/how...ders-settings/

shruggy · 02-10-2022, 09:53 AM

On CentOS, you reconfigure GRUB with grubby.

Hanisch · 02-10-2022, 10:03 AM

Quote:

Originally Posted by pan64

grub is the boot loader. This is the tool which will show that boot menu. You need to [re]configure it to forget the deleted kernel.
https://www.howtogeek.com/196655/how...ders-settings/

Sorry, I can't find the line to disable the TOP-Line in the Boot-menu.

Quote:

$ cat /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true
GRUB_DISABLE_SUBMENU=true
#GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto resume=UUID=0cffd2aa-a2ca-4ec5-aba0-07fc7fbd1a7b rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
GRUB_ENABLE_BLSCFG=true
#GRUB_BACKGROUND="/usr/share/backgrounds/default.png"
GRUB_BACKGROUND="/usr/share/backgrounds/default-mit-Text.tga"

with regards
Ch. Hanisch

pan64 · 02-10-2022, 10:08 AM

Quote:

Originally Posted by Hanisch

Sorry, I can't find the line to disable the TOP-Line in the Boot-menu.

Please follow post #13, that would be better I think