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