How to permanently disable crashkernel?

[embassyrow]

Hi, is there a way to permanently disable crashkernel?

We’ve stopped the service and set “crashkernel=no” in grubby by running the following commands:

systemctl stop kdump
systemctl disable kdump
grubby --update-kernel=ALL --args="crashkernel=no"

Unfortunately, upon kernel update, crashkernel is reactivated.

There was a thread about this last year expressing hope that the issue would be resolved in 9.4 but persists for us still in 9.5.

[iwalker]

This is how I do it:

Edit /etc/kdump.conf and change this from yes to no:

auto_reset_crashkernel no

Stop, disable and mask kdump service:

systemctl stop kdump
systemctl disable kdump
systemctl mask kdump

Upgrade grub config and reboot to recover lost memory
that was reserved for crashkernel:

grub2-mkconfig --update-bls-cmdline -o /boot/grub2/grub.cfg

That should do it.

[embassyrow]

Thank you, this seems to work.

We didn’t mask kdump but made the other changes per your recommendation and memory isn’t being reserved even after updating to a new kernel.

[iwalker]

I masked it because I found the system still starting the service for some bizarre reason. At least by masking it I could guarantee that nothing was going to try and start it. Anyway, glad it worked for you

[embassyrow]

When we tried this on a fresh install (even after masking kdump) and updated to a new kernel, memory was again being reserved for crashkernel.

Turns out we’d already run the following command on the other machines we had tested:

grubby --update-kernel=ALL --args=“crashkernel=no”

Running that before grub2-mkconfig on the new test machine and everything seems fine, even after update.

[iwalker]

Interesting, never had to do that. Usually updating the grub configuration with the bls stuff was enough.