mediumMultiple ChoiceObjective-mapped
XK0-006 Practice Question: A Linux server with systemd is experiencing boot…
A Linux server with systemd is experiencing boot issues after a recent kernel update. Which command sequence should be used to boot into the previous kernel version?
⚠ Common exam trap
A common mix-up: candidates confuse changing the default boot target (runlevel) with selecting a different kernel version, or they assume a package manager command can revert the running kernel without understanding that the bootloader controls which kernel is loaded at startup.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Interrupt the boot process, select 'Advanced options' in GRUB, then choose the previous kernel.
GRUB (Grand Unified Bootloader) stores multiple kernel versions in its menu. By interrupting the boot process and selecting 'Advanced options for Ubuntu' (or similar), you can choose the previous kernel entry, which loads the older kernel and its associated initramfs. This is the standard method to recover from a failed kernel update on systems using systemd and GRUB.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Boot from a live CD and run 'rpm -Uvh --oldkernel' to revert the kernel.
Why it's wrong here
Reinstalling kernel is not a boot-time selection.
- ✓
Interrupt the boot process, select 'Advanced options' in GRUB, then choose the previous kernel.
Why this is correct
Allows selection of a specific kernel version from the GRUB menu.
- ✗
Use 'systemctl set-default multi-user.target' and reboot.
Why it's wrong here
Sets the default target, not kernel version.
- ✗
Use 'grub2-set-default' with the previous kernel entry before rebooting.
Why it's wrong here
Sets default for next boot, but if already booting it's too late; interactive menu is better.
Go deeper
Related to this question
Learn chapter
Linux Fundamentals and History
Key term
Kernel
The kernel is the core program of an operating system that manages hardware resources and provides essential services for all other software to run.
Key term
GRUB
GRUB (Grand Unified Bootloader) is a boot loader package that loads and manages the operating system startup process on Linux and other Unix-like systems.
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