How do you view Grub command line options

https://forums.rockylinux.org/t/how-do-you-view-grub-command-line-options/11625

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Oct 2023 Dec 2023 post by keller_thomas on Oct 18, 2023 post by jlehtone on Oct 18, 2023 post by jbkt23 on Oct 18, 2023

jbkt23 Oct 2023 The “grubby” tool is what you use to modify the kernel parameters in RL9.

man grubby

To see the default kernel parameters you would issue the command thus:

grubby –info=DEFAULT or for all kernels

grubby –info=ALL and for a specific kernel

grubby –info=/boot/vmlinuz-5.14.0-284.18.1.el9_2.x86_64

index=2 kernel=”/boot/vmlinuz-5.14.0-284.18.1.el9_2.x86_64” args=”ro resume=UUID=71da8f2b-df89-4d45-b763-9768884fea6f selinux=0 $tuned_params crashkernel=1G-4G:192M,4G-64G:256M,64G-:512M” root=”UUID=7277c17d-6897-497b-9390-1153c9bff018” initrd=”/boot/initramfs-5.14.0-284.18.1.el9_2.x86_64.img $tuned_initrd” title=”Rocky Linux (5.14.0-284.18.1.el9_2.x86_64) 9.2 (Blue Onyx)” id=”ba3fd5ffa1514c2bb468fa289f69faa0-5.14.0-284.18.1.el9_2.x86_64”

Grubby modifies the boot loader definitions in /boot/loader/entries/ and creates the file /etc/kernel/cmdline that is used to populate your parameters upon new kernel installs.

post by keller_thomas on Oct 18, 2023

keller_thomas

jlehtone Oct 2023 We are using el9. We are still trying to get STIGs for el9 so was trying to figure out how to prove we are setting these and that the options are actually active.

post by quartsize on Oct 25, 2023

quartsize Oct 2023 Checking the actual config Grub’s going to get is trickier now with BLS – you have to believe that the

insmod blscfg blscfg in /boot/grub2/grub.cfg is going to produce what you think it should from /boot/loader/entries/*.conf. If it’s showing up in /proc/cmdline after you reboot, though, that confirms it’s making it that far.

Ultimately however the way of verifying that the kernel actually did something you requested on its command-line is going to be parameter-specific (for example, the kernel may reject an swiotlb= setting for being too large, so even though what you specified shows up in /proc/cmdline it’s not actually in effect). In your case, is audit=1 getting you anything new in dmesg that confirms it’s been enabled? I’m not super familiar with audit=, but it sounds like a full test might involve disabling auditd, rebooting, trying some loggable event, and ensuring auditd receives the log entry when started.

2 months later Closed on Dec 24, 2023

Closed on Dec 24, 2023