Red Hat Bugzilla – 2104534 – Confusing warning despite success - "sed: can't read /etc/default/grub: No such file or directory" when running kdumpctl reset-crashkernel --kernel=ALL on s390x
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Confusing warning despite success - "sed: can't read /etc/default/grub: No such file or directory" when running kdumpctl reset-crashkernel --kernel=ALL on s390x
Description of problem:
RHEL 9 documentation "11.1. Configuring kdump memory usage"[1] describes a way to reset the crashkernel size with kdumpctl. This command fails and customers on s390x seem to lack guidance about default values.
Version-Release number of selected component (if applicable):
kexec-tools-2.0.24-4.el9.s390x
How reproducible:
100%
Steps to Reproduce:
1. kdumpctl reset-crashkernel --kernel=ALL
Actual results:
sed: can't read /etc/default/grub: No such file or directory
sed: can't read /etc/default/grub: No such file or directory
Expected results:
The command succeeds; it updates the boot entries' crashkernel setting and runs 'zipl' to update the boot images.
Additional info:
[1]https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_monitoring_and_updating_the_kernel/configuring-kdump-on-the-command-line_managing-monitoring-and-updating-the-kernel
On s390x, per default BLS entries are used. I can successfully set a custom value via:
# grubby --update-kernel ALL --args "crashkernel=<CUSTOM-VALUE>”
# zipl
Note, on s390x, it's important to run 'zipl' after the grubby command (or usually after modifying kernel commandlines); if not the changes in the BLS entries won't be used when booting into the kernel; I verified this but I don't know the reason.
There's no grub support on s390x RHEL.
Customers can obtain the default crashkernel info via 'kdumpctl get-default-crashkernel' (verified on s390x, too).
Thanks for reporting this bug! Despite the warnings of "sed: can't read /etc/default/grub: No such file or directory", kdumpctl has successfully reset default crashkernel value. Note on s390x, /etc/defaut/grub doesn't exist (bz21051180). I'll skip updating /etc/defaut/grub for 390x.
(In reply to Coiby from comment #2)
> Thanks for reporting this bug! Despite the warnings of "sed: can't read
> /etc/default/grub: No such file or directory", kdumpctl has successfully
> reset default crashkernel value. Note on s390x, /etc/defaut/grub doesn't
> exist (bz21051180).
I meant bz2105118. Thanks Jie for correcting me.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (kexec-tools bug fix and enhancement update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2023:2463