LPIC-2 Linux Kernel and System Startup Practice Test 2 — 15 Questions

Question 1

During boot, the kernel panics with 'VFS: Unable to mount root fs on unknown-block(0,0)'. Which of the following is the most likely cause?

Accepted Answer

The kernel lacks the driver for the storage controller.. The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates the kernel cannot find a driver for the block device containing the root filesystem. This most commonly occurs when the kernel lacks the necessary storage controller driver (e.g., for SATA, NVMe, or SCSI controllers), often because the driver was built as a module and not included in the initramfs or compiled into the kernel.

Answer

The kernel image is corrupted.

Answer

The init process is missing.

Answer

The root filesystem is formatted with an unsupported filesystem.

Question 2

A technician is troubleshooting a system that fails to boot after adding a new SATA SSD and editing /etc/fstab. The error message is 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,17)'. What is the most likely issue?

Accepted Answer

The root filesystem UUID in /etc/fstab is incorrect.. The error 'unknown-block(8,17)' indicates the kernel cannot find the root filesystem. Block device 8,17 corresponds to /dev/sdb1 (major 8 for SCSI/SATA, minor 17). The most likely cause is an incorrect UUID in /etc/fstab, which prevents the system from mounting the root partition. The kernel can see the device, but the mount fails because the UUID specified does not match any available partition.

Answer

The kernel image is missing.

Answer

The kernel lacks SATA driver support.

Answer

The initramfs was not regenerated after adding the disk.

Question 3

Arrange the steps to configure a Linux server as an NFS client that mounts a remote export.

Accepted Answer

1. Install the nfs-common package
2. Create a mount point directory
3. Add an entry to /etc/fstab
4. Mount the remote export
5. Verify the mount. The NFS client needs the nfs-common package, a mount point, an fstab entry, then mounting and verification.

Answer

1. Install the nfs-common package
2. Add an entry to /etc/fstab
3. Create a mount point directory
4. Mount the remote export
5. Verify the mount

Answer

1. Create a mount point directory
2. Mount the remote export
3. Add an entry to /etc/fstab
4. Install the nfs-common package
5. Verify the mount

Answer

1. Add an entry to /etc/fstab
2. Create a mount point directory
3. Install the nfs-common package
4. Mount the remote export
5. Verify the mount

Question 4

Order the steps to configure a Linux system as an SSH server with key-based authentication.

Accepted Answer

Install SSH server, then configure SSH server, then generate SSH key pair, then copy public key to server, then restart SSH service and test.. Install SSH server, configure it, generate keys, copy public key, restart and test.

Answer

Generate SSH key pair, then install SSH server, then configure SSH server, then copy public key, then restart and test.

Answer

Install SSH server, then generate SSH key pair, then copy public key, then configure SSH server, then restart and test.

Answer

Install SSH server, then configure SSH server, then copy public key, then generate SSH key pair, then restart and test.

Question 5

Match each Linux filesystem feature to its description.

Accepted Answer

ext4: A journaling filesystem that is the default for many Linux distributions, supporting extents and large files.. The correct matches are ext4 (default journaling filesystem), XFS (high-performance parallel I/O), Btrfs (copy-on-write with snapshots), and F2FS (flash-friendly). Common confusions include swapping ext4 with Btrfs and XFS with F2FS.

Answer

ext4: A copy-on-write filesystem with built-in snapshot and compression capabilities.

Answer

XFS: A flash-friendly filesystem designed for NAND flash storage, minimizing write amplification.

Question 6

Match each Linux boot component to its role.

Accepted Answer

GRUB: Bootloader that loads the kernel and initramfs.. The correct matches are: GRUB loads kernel and initramfs; initramfs is a temporary root filesystem; kernel manages hardware and processes; init/systemd is the first process. Common confusions include MBR being mistaken for a kernel loader and initramfs for GRUB config storage.

Answer

MBR: Loads the Linux kernel.

Answer

initramfs: Contains the GRUB configuration.

Question 7

A system administrator needs to include a custom kernel module in the initramfs to support a root filesystem on a USB device. Which command should be used to rebuild the initramfs with the updated kernel?

Accepted Answer

dracut. Dracut is the correct tool for rebuilding the initramfs on modern Red Hat-based distributions (e.g., RHEL, CentOS, Fedora). It automatically detects and includes kernel modules required for the root filesystem, including those for USB storage devices, and regenerates the initramfs image with the updated kernel module.

Answer

update-initramfs

Answer

mkinitrd

Answer

grub-mkconfig

Question 8

During boot, the kernel panics because the root filesystem cannot be mounted. Which kernel parameter should be added at the GRUB prompt to try an alternative root device?

Accepted Answer

root=/dev/sdb1. The kernel parameter 'root=' specifies the device for the root filesystem. When the default root device fails to mount, adding 'root=/dev/sdb1' at the GRUB prompt overrides the compiled-in root and tells the kernel to attempt mounting from that alternative block device. This is the standard method to redirect the root mount during boot troubleshooting.

Answer

init=/bin/sh

Answer

rescue

Answer

single

Question 9

A system administrator compiled a custom kernel module for a new hardware device. After copying the .ko file to /lib/modules/$(uname -r)/, the module is not loading automatically at boot. What is the most likely cause?

Accepted Answer

The module is blacklisted in /etc/modprobe.d/.. A blacklist entry in /etc/modprobe.d/ explicitly prevents the kernel from loading the module at boot, regardless of its presence in /lib/modules/$(uname -r)/. The modprobe system reads these configuration files during early boot and skips any module listed with a 'blacklist' directive, which is the most likely cause when a module is present but fails to load automatically.

Answer

The module needs to be added to /etc/modules.

Answer

The module has a dependency error.

Answer

The kernel version does not match the module.

Question 10

An administrator wants to compile a new kernel module that is not yet in the tree. What file should be referenced to ensure the module is built with the same configuration as the current kernel?

Accepted Answer

/boot/config-5.10.0-9-amd64. /boot/config-5.10.0-9-amd64 contains the exact kernel configuration used to build the currently running kernel. When compiling a new kernel module, referencing this file (typically via 'make oldconfig' or copying it to the source tree as .config) ensures the module is built with the same set of options, such as enabled features, drivers, and module parameters, preventing incompatibilities.

Answer

/proc/config.gz

Answer

/boot/System.map-5.10.0-9-amd64

Answer

/boot/initrd.img-5.10.0-9-amd64

Question 11

Which file is used by GRUB2 to load the kernel and initramfs?

Accepted Answer

/boot/grub/grub.cfg. GRUB2 uses /boot/grub/grub.cfg as its main configuration file, which contains the menu entries, kernel paths, and initramfs locations. This file is generated by update-grub (or grub-mkconfig) based on scripts in /etc/grub.d/ and settings in /etc/default/grub, and it is read directly by the GRUB2 bootloader at boot time to load the kernel and initramfs.

Answer

/etc/lilo.conf

Answer

/etc/default/grub

Answer

/boot/grub/menu.lst

Question 12

An administrator wants to ensure a kernel module is loaded automatically at boot for a hardware device. Which file should be modified to add the module name?

Accepted Answer

/etc/modules-load.d/. The `/etc/modules-load.d/` directory contains configuration files that list kernel module names to be loaded automatically at boot by the `systemd-modules-load.service`. This is the standard mechanism in modern Linux distributions using systemd to ensure specific modules are loaded early in the boot process, before udev or other services handle device detection.

Answer

/etc/modprobe.d/blacklist.conf

Answer

/etc/udev/rules.d/

Answer

/proc/sys/kernel/

Question 13

After upgrading the kernel on a Red Hat Enterprise Linux system, the system fails to boot because the initramfs is missing. Which command can be used to regenerate the initramfs?

Accepted Answer

dracut -f. On Red Hat Enterprise Linux (RHEL) systems, the `dracut` utility is the standard tool for creating and regenerating initial RAM filesystem images (initramfs). The `-f` (force) option overwrites an existing initramfs file, which is necessary after a kernel upgrade to ensure the new kernel has the correct drivers and modules to mount the root filesystem during boot. Without a valid initramfs, the kernel cannot access the root filesystem, causing a boot failure.

Answer

mkinitrd -f

Answer

grub2-mkconfig -o /boot/grub2/grub.cfg

Answer

mkinitramfs -o /boot/initrd.img

Question 14

An administrator wants to disable the graphical splash screen during boot. What change should be made in /etc/default/grub?

Accepted Answer

Remove 'splash' from GRUB_CMDLINE_LINUX_DEFAULT. The graphical splash screen during boot is controlled by the 'splash' kernel parameter. Removing 'splash' from GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub disables the splash screen, allowing verbose boot messages to be displayed. This parameter is passed to the kernel via the bootloader, and its absence prevents the plymouth or similar splash service from activating.

Answer

Set GRUB_CMDLINE_LINUX="nosplash"

Answer

Remove 'quiet' from GRUB_CMDLINE_LINUX_DEFAULT

Answer

Set GRUB_TIMEOUT=0

Question 15

A system has multiple kernels installed. Which command shows the version of the currently booted kernel?

Accepted Answer

uname -r. The `uname -r` command specifically displays the kernel release (version) of the currently running operating system. It reads this information directly from the `/proc/sys/kernel/osrelease` virtual file, which is populated by the kernel at boot time. This makes it the most direct and reliable method to identify the active kernel version.

Answer

rpm -qa | grep kernel

Answer

cat /proc/version

Answer

ls /boot