CCNA System Architecture Questions — Page 1 of 2

MCQmedium

Refer to the exhibit. How many physical disks are detected by the kernel, and what are their sizes?

A.Two disks: sda 10.0 GiB, sdb 2.00 GiB

B.Two disks: sda 10.7 GB, sdb 2.15 GB

C.Three disks: sda, sdb, and an unknown device

D.One disk: sda 10.7 GB

AnswerA

Correctly matches the output sizes in GiB.

Why this answer

The output shows two disks: sda with 20971520 logical blocks of 512 bytes = 10737418240 bytes = 10.0 GiB, and sdb with 4194304 blocks = 2147483648 bytes = 2.00 GiB. The sizes are given in GiB in the output.

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MCQeasy

Which command shows the amount of free and used memory in the system, including swap?

A.top

B.free -h

C.df -h

D.vmstat

AnswerB

free -h specifically shows memory usage with swap.

Why this answer

free -h displays memory and swap usage in human-readable format. It shows total, used, free, and buffers/cache.

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MCQeasy

A small office server running Ubuntu 20.04 experiences a gradual time drift. The system clock loses about 2 minutes per week. The hardware clock (RTC) is maintained by the motherboard battery and appears accurate when checked manually. The sysadmin wants to ensure the system clock stays synchronized automatically. Which single action should be taken? Options: A) Run 'timedatectl set-ntp true' to enable systemd-timesyncd, B) Add 'hwclock --hctosys' to /etc/rc.local, C) Install and configure the ntp package with a pool server, D) Use 'cron' to run ntpdate every minute.

A.Install and configure the ntp package with a pool server

B.Add 'hwclock --hctosys' to /etc/rc.local

C.Use 'cron' to run ntpdate every minute

D.Run 'timedatectl set-ntp true' to enable systemd-timesyncd

AnswerD

Enables a lightweight SNTP client that keeps time synchronized.

Why this answer

Option A enables the integrated SNTP client in systemd, which is the simplest solution for most desktops/servers. Option B only syncs at boot, not continuously. Option C is valid but overkill for 2 minutes/week drift; the simpler solution works.

Option D is inefficient and may cause rapid clock adjustments. Thus A is best.

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MCQeasy

Which hardware component uses a unique address to identify itself on the network at the data link layer?

A.IP address

B.MAC address

C.Hostname

D.Port number

AnswerB

MAC addresses are used for communication within a local network segment.

Why this answer

The MAC address (Media Access Control) is a unique 48-bit identifier burned into the network interface controller (NIC) by the manufacturer. It operates at Layer 2 (data link layer) of the OSI model, enabling devices on the same local network segment to communicate directly using protocols like Ethernet or Wi-Fi.

Exam trap

The trap here is that candidates often confuse the MAC address with the IP address because both are used for network identification, but the question specifically asks for the data link layer, where only the MAC address (not the IP address) operates.

How to eliminate wrong answers

Option A is wrong because an IP address operates at Layer 3 (network layer) and is used for logical addressing and routing across networks, not for hardware identification at the data link layer. Option C is wrong because a hostname is a human-readable alias resolved to an IP address via DNS or local hosts files, and it has no role in data link layer addressing. Option D is wrong because a port number is a Layer 4 (transport layer) identifier used by TCP or UDP to distinguish application services on a host, not for hardware-level network identification.

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MCQmedium

On a systemd-based system, which file is NOT used for system initialization?

A./etc/fstab

B./etc/systemd/system/default.target

C./etc/inittab

D./lib/systemd/system/sysinit.target

AnswerC

Inittab is for SysV init, not systemd.

Why this answer

The correct option is D: /etc/inittab is used by SysV init, not systemd. Option A (/etc/systemd/system/default.target) is a symlink to the default target. Option B (/lib/systemd/system/sysinit.target) is a systemd target used early in boot.

Option C (/etc/fstab) is used by systemd to mount filesystems.

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MCQhard

After a system upgrade, the server fails to boot with the error: 'ERROR: Failed to mount the real root device.' The root filesystem is on an LVM logical volume. Which recovery step is most appropriate?

A.Boot from a live CD, chroot, and run 'update-initramfs -u -k all' to regenerate the initramfs with lvm2 support

B.Run 'lvchange -ay' to activate all LVs

C.Reinstall GRUB to the MBR

D.Use 'fsck' on the root LV

AnswerA

This rebuilds the initramfs including necessary LVM modules.

Why this answer

Option A (reinstall GRUB) does not address missing LVM modules. Option B (regenerate initramfs with lvm2 hook) ensures the initramfs contains LVM tools and modules. Option C (check LVM metadata) is a later step.

Option D (use fsck) may corrupt LVM if run on an LV. Thus B is correct.

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MCQhard

A sysadmin wants to ensure a specific kernel module is automatically loaded at boot. Which method is considered best practice?

A.Use systemd-modules-load.service

B.All of the above are valid methods

C.Add module name to /etc/modules

D.Add a line to /etc/modprobe.d/

AnswerB

All three are valid and best practices for loading modules at boot.

Why this answer

Correct: D. All three methods (adding a line to /etc/modprobe.d/, using systemd-modules-load.service, or adding the module name to /etc/modules) are valid ways to load a module at boot. Options A, B, C are each correct individually, but D encompasses all.

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MCQeasy

A system administrator is troubleshooting a Linux server that fails to boot. The server has a software RAID 1 configuration using mdadm, with the root filesystem located on /dev/md0. During boot, the system halts with the following error: 'VFS: Unable to mount root fs on unknown-block(0,0)'. The admin verifies that the BIOS recognizes all disks and that the RAID array was properly assembled prior to the last shutdown. The system was working after a recent kernel update, but now fails. Which of the following actions is the most likely solution?

A.Use a live CD to run fsck on /dev/md0.

B.Rebuild the initramfs to include the mdadm module and the RAID metadata.

C.Check the /etc/fstab file for incorrect root device.

D.Reinstall the bootloader on the MBR.

AnswerB

Rebuilding the initramfs adds the necessary RAID support, allowing the kernel to assemble and mount /dev/md0.

Why this answer

Option D is correct because the error indicates the kernel cannot find the root filesystem device. After a kernel update, the initramfs may not contain the necessary mdadm modules and RAID metadata support. Rebuilding the initramfs with mdadm support (e.g., using mkinitramfs or dracut) includes the required modules and fixes the boot issue.

Option A is incorrect because the bootloader already loads the kernel; the problem occurs after that. Option B is incorrect because /etc/fstab is read after the root filesystem is mounted. Option C is incorrect because /dev/md0 is not available at the point of the error, so fsck cannot be run.

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MCQeasy

A system administrator notices that after updating the kernel, the system fails to boot. The administrator wants to boot the previous kernel. Which GRUB menu option should be selected?

A.Memory test

B.Advanced options for Ubuntu

C.Recovery mode

D.Boot from first hard disk

AnswerB

This option often lists previous kernel versions.

Why this answer

The correct option is A: 'Advanced options for Ubuntu' typically lists older kernels available for boot. Option B (Recovery mode) is for recovery, not selecting a different kernel. Option C (Memory test) is unrelated.

Option D (Boot from first hard disk) boots the default entry, not a specific kernel.

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MCQhard

A kernel module fails to load with the error 'modprobe: FATAL: Module xyz not found in directory /lib/modules/$(uname -r)'. What is the most likely cause?

A.The module is blacklisted in /etc/modprobe.d/.

B.The kernel version has changed and modules need to be rebuilt.

C.The module has dependencies that are missing.

D.The module is not installed on the system.

AnswerB

After a kernel update, modules for the new kernel may not be present; they need to be rebuilt or reinstalled.

Why this answer

The error indicates that the module is not present for the currently running kernel version. This often happens after a kernel update without rebuilding the modules.

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Multi-Selecteasy

Which THREE of the following are valid runlevels in a traditional SysV init system? (Choose three.)

Select 3 answers

A.9

B.6

C.7

D.1

E.0

AnswersB, D, E

Runlevel 6 is reboot.

Why this answer

Standard runlevels are 0 (halt), 1 (single-user), 2 (multi-user without NFS), 3 (full multi-user), 4 (unused), 5 (graphical), 6 (reboot). Options 7 and 9 are not standard runlevels.

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MCQhard

A production server running CentOS 7 has multiple SCSI disks (sda, sdb, sdc) configured in a RAID5 array managed by mdadm (md0). The root filesystem is on md0. After a power failure, the server boots but drops into a rescue shell with the error: 'md: md0: cannot run array. Not enough devices online.' The admin checks with 'cat /proc/mdstat' and sees that only sda and sdb are spares (marked as (S)), sdc is missing. Which sequence of commands should the admin use to attempt recovery and bring the system to a functional state? Options: A) First run 'mdadm --manage /dev/md0 --add /dev/sdc', then 'mdadm --run /dev/md0'. B) Boot from a live CD, then run 'mdadm --assemble --scan' to reassemble. C) Run 'mdadm --stop /dev/md0', then 'mdadm --assemble /dev/md0 /dev/sda /dev/sdb /dev/sdc'. D) Run 'mdadm --run /dev/md0' to force start the array in degraded mode, then add sdc with 'mdadm --add' after system is up.

A.Run 'mdadm --run /dev/md0' to force start the array in degraded mode, then add sdc with 'mdadm --add' after system is up

B.Boot from a live CD, then run 'mdadm --assemble --scan' to reassemble

C.Run 'mdadm --manage /dev/md0 --add /dev/sdc', then 'mdadm --run /dev/md0'

D.Run 'mdadm --stop /dev/md0', then 'mdadm --assemble /dev/md0 /dev/sda /dev/sdb /dev/sdc'

AnswerA

Starts the array with 2 devices (degraded), then adds the missing disk for rebuild.

Why this answer

Option D is correct: the array is not started because not enough devices are online. Forcing start (--run) activates the array in degraded mode (with two devices, RAID5 needs at least 3? Actually RAID5 with 3 devices can tolerate 1 missing disk, so 2 devices online is enough for degraded mode). Then adding the missing disk rebuilds.

Option A attempts add before array is running; --add only works on active arrays. Option B is possible but unnecessary if rescue shell has mdadm. Option C is correct if the disks are present but not assembled; however, the missing disk sdc is not present, so assembly will fail.

The best immediate step is to start the array in degraded mode. So D is correct.

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Multi-Selectmedium

Which TWO commands can be used to display information about the CPU(s) in a Linux system? (Choose two.)

Select 2 answers

A.uname -m

B.lsusb

C.cpufreq-info

D.cat /proc/cpuinfo

E.lscpu

AnswersD, E

cat /proc/cpuinfo shows detailed per-CPU information.

Why this answer

lscpu and cat /proc/cpuinfo both provide comprehensive CPU information. lsusb shows USB devices, cpufreq-info shows CPU frequency scaling, and uname -m shows machine hardware architecture.

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MCQhard

A server configured with UEFI firmware and GPT partitioning fails to boot after a GRUB package update. The administrator suspects the bootloader is not correctly installed. Which command should be used to reinstall GRUB to the EFI system partition?

A.grub2-install /dev/sda1

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

C.grub-install /dev/sda

D.grub-install --target=x86_64-efi --efi-directory=/boot/efi

AnswerD

Correctly installs GRUB for UEFI, targeting the EFI system partition mounted at /boot/efi.

Why this answer

For UEFI systems, grub-install must include the target and efi-directory. Option B specifies x86_64-efi target and the EFI directory /boot/efi, which is correct.

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MCQmedium

A Linux system using systemd fails to reach the default target after a recent change. The administrator wants to boot into a minimal environment to troubleshoot. Which kernel parameter should be added at the GRUB prompt?

A.single

B.systemd.unit=rescue.target

C.init=/bin/bash

D.systemd.unit=emergency.target

AnswerB

Rescue target provides a minimal environment with root read-write and basic services.

Why this answer

The correct option is C: systemd.unit=rescue.target boots into a minimal environment with basic services. Option A (systemd.unit=emergency.target) is even more minimal but does not mount filesystems read-write. Option B (init=/bin/bash) bypasses systemd entirely.

Option D (single) is a SysV init parameter, not systemd.

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MCQmedium

A Linux system administrator is tasked with setting up a new server that will host multiple virtual machines using KVM. The server has 64 GB of RAM and two physical CPUs, each with 8 cores (16 threads). The administrator needs to allocate resources efficiently. The VMs will have varying workloads. The administrator wants to ensure that the host system has enough resources for itself and that VMs can use all available CPU cores. Which approach should the administrator take to configure CPU allocation for the host and VMs?

A.Use QEMU emulation instead of KVM to reduce CPU overhead.

B.Pin all physical CPU cores to the VMs using virsh vcpupin, and leave no cores for the host.

C.Use CPU pinning to reserve two physical cores for the host and distribute the remaining cores among VMs using host-passthrough mode.

D.Overcommit CPU resources by assigning 32 vCPUs to each VM, relying on the hypervisor to schedule.

AnswerC

This ensures host responsiveness and allows VMs to use all available CPU features.

Why this answer

Option C is correct because it reserves two physical cores for the host system to ensure its stability and performance, while distributing the remaining cores among VMs using CPU pinning and host-passthrough mode. This approach allows VMs to access the full CPU feature set and all available cores efficiently, balancing host overhead with VM resource needs in a KVM environment.

Exam trap

The trap here is that candidates may assume overcommitting CPU resources is always safe (Option D) or that QEMU emulation is a performance improvement (Option A), when in fact KVM's hardware acceleration and proper pinning are critical for efficient virtualization.

How to eliminate wrong answers

Option A is wrong because QEMU emulation adds significant CPU overhead compared to KVM's hardware-assisted virtualization, which would degrade performance rather than reduce it. Option B is wrong because pinning all physical cores to VMs leaves no CPU resources for the host, causing the host to starve and potentially crash or become unresponsive. Option D is wrong because overcommitting CPU resources by assigning 32 vCPUs per VM (exceeding the total 32 threads) can lead to severe contention and performance degradation, as the hypervisor cannot efficiently schedule such an extreme overcommitment without proper resource limits.

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MCQhard

After modifying the /etc/fstab file, an administrator runs the command mount -a and receives the error 'mount: /data: special device /dev/sdb1 does not exist'. What is the most likely issue?

A.There is a typo in the device path in /etc/fstab.

B.The /dev/sdb1 device file is missing or corrupted.

C.The entry in /etc/fstab has an incorrect filesystem type.

D.The filesystem on /dev/sdb1 is not formatted.

AnswerA

A typo would cause the kernel to not find the device at the specified path, resulting in the 'does not exist' error.

Why this answer

The error states the special device (block device) does not exist. This typically means the device path specified in fstab is incorrect or the device itself is absent. After fstab modification, a typo in the device path is the most plausible cause.

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MCQhard

Refer to the exhibit. The system has multiple SAS drives attached to this controller, but one of them is not detected during boot. Which command is most likely to provide information about the device detection order?

A.cat /proc/scsi/scsi

B.lsblk

C.dmesg | grep -i scsi

D.lsscsi

AnswerC

dmesg displays kernel messages with timestamps, revealing the order of SCSI device detection.

Why this answer

Option B is correct because dmesg shows kernel ring buffer messages with timestamps, allowing you to see the order in which devices were detected. Option A (lsblk) shows block devices but not detection order. Option C (lsscsi) lists SCSI devices currently present but not their order.

Option D (cat /proc/scsi/scsi) shows attached SCSI devices but not detection order.

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Multi-Selectmedium

Which TWO of the following are valid methods to view kernel messages on a systemd-based system?

Select 2 answers

A.lsmod

B.journalctl -k

C.cat /var/log/syslog

D.grub-mkconfig

E.dmesg

AnswersB, E

Shows kernel messages from the systemd journal for the current boot.

Why this answer

Correct options are A and B. dmesg displays the kernel ring buffer (current boot). journalctl -k shows kernel messages from the systemd journal (current boot by default). Option C (cat /var/log/syslog) may contain kernel messages but is not kernel-specific. Option D (lsmod) lists loaded modules.

Option E (grub-mkconfig) generates GRUB config.

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Multi-Selectmedium

Which TWO commands can be used to set the default boot target (runlevel) in systemd?

Select 2 answers

A.ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target

B.systemctl isolate multi-user.target

C.systemctl default multi-user.target

D.systemctl enable multi-user.target

E.systemctl set-default multi-user.target

AnswersA, E

Manually creates the symlink for default target.

Why this answer

Options A and D are correct: 'systemctl set-default' changes the default target, and manually creating a symlink to the desired target in /etc/systemd/system/ also sets it. Option B is not a valid command, C enables a service, not default target, and E changes the current target temporarily.

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MCQeasy

Based on the exhibit, which statement is true?

A.The disk has write protection enabled

B.The disk has 5 partitions

C.The disk is 1 TB

D.The disk uses GPT partitioning

AnswerC

The log explicitly states 1.00 TB.

Why this answer

Correct: C. The log shows '1953525168 512-byte logical blocks: (1.00 TB/931 GiB)', confirming the disk is 1 TB. Option A is false because only sda1 and sda2 partitions are detected; B is not indicated; D is false because Write Protect is off.

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MCQeasy

A junior admin is tasked with configuring network bonding on a Debian server with two Ethernet interfaces, eth0 and eth1. The goal is to provide link redundancy using active-backup mode. The admin edits /etc/network/interfaces and adds configuration for bond0 with slaves eth0 eth1, then runs 'ifup bond0'. However, the bond interface fails to come up and the error message indicates that the 'bond' kernel module is not loaded. The admin checks with 'lsmod | grep bonding' and finds no output. Which additional step is required to successfully bring up the bond interface? Options: A) Run 'modprobe bonding' before ifup, B) Add 'auto bond0' in /etc/network/interfaces, C) Use ifenslave directly after ifup, D) Reboot the system to load the module.

A.Run 'modprobe bonding' before ifup

B.Use ifenslave directly after ifup

C.Reboot the system to load the module

D.Add 'auto bond0' in /etc/network/interfaces

AnswerA

Loads the bonding kernel module, enabling bond interface creation.

Why this answer

Option A is correct because the bonding module must be loaded before the bond interface can be created. 'modprobe bonding' loads the kernel module. Option B is irrelevant; 'auto' ensures interface starts at boot but doesn't load the module. Option C is unnecessary if bonding is configured via interfaces; ifenslave is for manual bonding.

Option D is overkill; rebooting may load the module if configured, but loading manually is quicker. So A is correct.

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MCQhard

After connecting a USB device, the system does not create a device node in /dev. Which command can be used to trigger udev to re-evaluate the device?

A.modprobe

B.udevadm control --reload

C.udevadm settle

D.udevadm trigger

AnswerD

This command generates uevents for existing devices, causing udev to process them again.

Why this answer

The correct option is A: udevadm trigger forces udev to re-evaluate all devices. Option B (udevadm control --reload) reloads rules but does not trigger events. Option C (udevadm settle) waits for pending events.

Option D (modprobe) loads kernel modules, not udev event processing.

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Multi-Selecthard

Which THREE of the following are valid sources to configure GRUB?

Select 3 answers

A./boot/grub/menu.lst

B./etc/grub.conf

C./boot/grub/grub.cfg

D./etc/default/grub

E./etc/grub.d/

AnswersC, D, E

The actual boot configuration file read by GRUB.

Why this answer

Options A, B, and C are correct: /etc/default/grub contains user settings, /boot/grub/grub.cfg is the generated configuration, and /etc/grub.d/ contains scripts that generate grub.cfg. Options D and E are legacy locations for older GRUB versions.

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MCQhard

A system administrator needs to blacklist the kernel module 'pcspkr' to disable the PC speaker. Which is the correct method?

A.Add 'blacklist pcspkr' to /etc/modprobe.d/blacklist.conf

B.Add 'load pcspkr' to /etc/modules

C.Add 'install pcspkr /bin/true' to /etc/modprobe.d/blacklist.conf

D.Remove the module from /lib/modules/$(uname -r)/kernel/drivers

AnswerA

The blacklist directive in modprobe configuration prevents the module from loading.

Why this answer

The correct option is B: Add 'blacklist pcspkr' to a file in /etc/modprobe.d/. Option A removes the module file, which is excessive and may break dependencies. Option C adds a dummy install command, but the 'blacklist' directive is the standard method.

Option D loads the module, not blacklist it.

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MCQeasy

Which file is used by GRUB to load the kernel at boot time?

A./etc/grub.d/

B./etc/default/grub

C./boot/vmlinuz

D./boot/grub/grub.cfg

AnswerD

This is the generated configuration file used by GRUB at boot.

Why this answer

Option A is the actual configuration file that GRUB reads. Option B contains default settings, C is the kernel image, D are scripts that generate the config.

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MCQmedium

A Linux administrator manages a server that runs a custom application requiring a specific kernel module to be loaded at boot. The server uses SysV init and has the module listed in /etc/modules. However, after a recent kernel update, the module fails to load automatically at boot. The administrator can manually load the module with 'modprobe <module>' after the system is running. The application depends on this module being loaded before any network services start. Which of the following actions should the administrator take to ensure the module loads automatically at the correct time during boot?

A.Create a SysV init script that loads the module and place it in /etc/init.d/ with appropriate symlinks in /etc/rc?.d/ to ensure it runs before network services.

B.Add the module name to /etc/modules-load.d/ directory.

C.Add an install directive in /etc/modprobe.d/ for the module.

D.Add a blacklist entry for the module in /etc/modprobe.d/blacklist.conf.

AnswerA

This ensures the module is loaded early in the boot process, before network services that depend on it.

Why this answer

Option A is correct because SysV init systems use init scripts in /etc/init.d/ with symlinks in /etc/rc?.d/ to control the order of service startup. By creating a custom init script that loads the module via modprobe and placing it with a symlink that has a lower number (e.g., S01module) than network services (e.g., S10network), the module will be loaded before network services start, satisfying the application's dependency.

Exam trap

The trap here is that candidates confuse the systemd-based /etc/modules-load.d/ mechanism with SysV init's /etc/modules file, assuming both are equivalent, when in fact SysV init requires explicit init scripts to control boot order.

How to eliminate wrong answers

Option B is wrong because /etc/modules-load.d/ is used by systemd's modules-load service, not by SysV init; on a SysV init system, this directory is ignored. Option C is wrong because an install directive in /etc/modprobe.d/ controls how modprobe handles module dependencies or custom commands when the module is requested, but it does not trigger automatic loading at boot; it only modifies modprobe behavior when the module is explicitly loaded. Option D is wrong because adding a blacklist entry would prevent the module from loading automatically, which is the opposite of what the administrator needs.

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Multi-Selecthard

Which TWO files are used to configure kernel boot parameters in GRUB?

Select 2 answers

A./sys/kernel/cmdline

B./etc/default/grub

C./etc/grub.d/

D./proc/cmdline

E./boot/grub/grub.cfg

AnswersB, E

Main configuration file for GRUB 2.

Why this answer

Correct: A and B. /etc/default/grub is the configuration file for GRUB 2; /boot/grub/grub.cfg is the generated boot menu file. Option C /proc/cmdline shows current parameters but is not config; D /sys/kernel/cmdline is not a config; E /etc/grub.d/ contains scripts that generate grub.cfg, but not directly.

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MCQmedium

A Linux system has two network interfaces: eth0 and eth1. The administrator wants to bond them for increased throughput. Which kernel module is required for bonding?

A.aggregation

B.bonding

C.team

D.bond

AnswerB

The bonding kernel module provides network interface bonding.

Why this answer

The bonding driver in Linux allows multiple network interfaces to be aggregated into a single logical interface for increased throughput or redundancy. The correct kernel module is named 'bonding' (loaded via modprobe bonding or compiled into the kernel), which implements the IEEE 802.3ad Link Aggregation standard and other bonding modes. Option B is correct because 'bonding' is the exact module name used in the Linux kernel.

Exam trap

The trap here is that candidates confuse the interface name (bond0) with the kernel module name (bonding), or think 'team' is a synonym for bonding, when in fact they are separate technologies with different kernel modules.

How to eliminate wrong answers

Option A is wrong because 'aggregation' is a generic term for combining links, not a specific Linux kernel module; the actual module is 'bonding'. Option C is wrong because 'team' refers to the libteam project, which is a separate user-space-based teaming solution that uses the 'team' kernel module, not the standard bonding driver. Option D is wrong because 'bond' is a common abbreviation but not the exact kernel module name; the module is loaded as 'bonding' (e.g., modprobe bonding), and the resulting interface is named bond0, bond1, etc.

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MCQmedium

The system administrator wants to use the entire sdb disk as a single partition. Which command will partition sdb with a single partition occupying the whole disk?

A.fdisk /dev/sdb, then create a new primary partition accepting all defaults

B.dd if=/dev/zero of=/dev/sdb bs=1M count=1

C.mkfs.ext4 /dev/sdb

D.parted /dev/sdb mklabel gpt && parted /dev/sdb mkpart primary 0% 100%

AnswerD

Correctly creates a GPT label and a partition spanning the entire disk.

Why this answer

Correct: B. The parted command 'mklabel gpt' creates a GPT partition label, then 'mkpart primary 0% 100%' creates a partition that uses the entire disk. Option A requires multiple steps; C zeroes the first MB; D attempts to create a filesystem directly on the disk without a partition.

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MCQmedium

An administrator wants to add a kernel parameter 'quiet splash' to the default boot entry. Which file should be edited?

A./etc/default/grub

B./etc/grub.d/00_header

C./etc/grub.conf

D./boot/grub/grub.cfg

AnswerA

This is the configuration file where kernel parameters are set and then applied by running update-grub.

Why this answer

The correct option is B: /etc/default/grub contains the GRUB_CMDLINE_LINUX_DEFAULT variable where parameters like 'quiet splash' are added. Option A (/boot/grub/grub.cfg) is auto-generated and should not be edited directly. Option C (/etc/grub.d/00_header) is a script.

Option D (/etc/grub.conf) is used by older GRUB legacy.

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MCQmedium

The system administrator wants to add a new swap partition on /dev/sdb2. After creating the partition, which command should be used to initialize it as swap?

A.mkfs.ext4 /dev/sdb2

B.fsck /dev/sdb2

C.mkswap /dev/sdb2

D.swapon /dev/sdb2

AnswerC

mkswap sets up a Linux swap area.

Why this answer

The correct option is A: mkswap initializes a partition as swap space. Option B (swapon) activates an existing swap partition. Option C (mkfs.ext4) creates an ext4 filesystem, not swap.

Option D (fsck) checks filesystems.

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MCQmedium

A technician is troubleshooting a system that fails to boot with the error 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. What is the most likely cause?

A.The init binary is missing or corrupted.

B.The root filesystem is corrupted and needs fsck.

C.The kernel lacks the necessary driver for the storage controller.

D.The boot loader is not installed correctly.

AnswerC

Kernel cannot access the root device due to missing storage driver.

Why this answer

The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates that the kernel cannot locate or access the root filesystem. This typically occurs because the kernel lacks the necessary driver (module) for the storage controller (e.g., SATA, SCSI, NVMe) that the root device is connected to, so it cannot read the partition table or mount the root filesystem.

Exam trap

The trap here is that candidates often confuse a root filesystem corruption error with a missing storage driver error, because both can prevent booting, but the specific 'unknown-block(0,0)' message uniquely points to the kernel's inability to identify the block device, not a filesystem issue.

How to eliminate wrong answers

Option A is wrong because a missing or corrupted init binary would cause a different error, such as 'Kernel panic - not syncing: No init found' or 'Failed to execute /sbin/init', not a VFS mount failure on unknown-block(0,0). Option B is wrong because a corrupted root filesystem would typically produce filesystem-specific errors (e.g., 'EXT4-fs error') or a kernel panic with a different message, not the unknown-block(0,0) error which indicates the device itself is unrecognized. Option D is wrong because an incorrectly installed boot loader would prevent the kernel from being loaded at all (e.g., 'Missing operating system' or 'GRUB error'), not cause the kernel to fail mounting the root filesystem after it has already started executing.

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MCQeasy

Which directory contains information about hardware devices in a hierarchical structure, such as PCI devices and USB devices?

A./sys

B./dev

C./etc

D./proc

AnswerA

/sys (sysfs) provides detailed device hierarchy and attributes.

Why this answer

/sys is the sysfs filesystem that exposes information about devices and drivers in a hierarchical manner.

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MCQeasy

The administrator wants the sshd service to start automatically at boot. Which command should be used?

A.systemctl start sshd.service

B.systemctl daemon-reload

C.systemctl set-default multi-user.target

D.systemctl enable sshd.service

AnswerD

Enables the service to start automatically at boot.

Why this answer

The correct option is B: systemctl enable sshd.service creates symlinks to start the service at boot. Option A (systemctl start) starts the service now but does not enable boot start. Option C (systemctl set-default multi-user.target) changes default target, unrelated.

Option D (systemctl daemon-reload) reloads systemd configuration.

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MCQmedium

Which command can be used to check whether a specific kernel module is currently loaded?

A.modinfo <module>

B.lsmod | grep <module>

C.depmod -a

D.insmod <module>

AnswerB

lsmod lists loaded modules; grep filters.

Why this answer

Correct: B. The command 'lsmod | grep <module>' lists loaded modules and filters for the desired module. Option A (modinfo) shows information about a module but not whether it's loaded; C (insmod) loads a module; D (depmod) generates module dependencies.

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Multi-Selectmedium

Which TWO commands can display the UUID of block devices?

Select 2 answers

A.blkid

B.lsblk -f

C.df -T

D.fdisk -l

E.parted /dev/sda print

AnswersA, B

blkid displays block device attributes including UUID.

Why this answer

Correct: A and B. 'blkid' shows UUID of all block devices; 'lsblk -f' also shows UUID. Option C 'fdisk -l' does not show UUID; D 'parted' show partition table but not UUID; E 'df -T' shows filesystem type but not UUID.

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MCQeasy

Which command displays information about currently loaded kernel modules?

A.insmod

B.modinfo

C.lsmod

D.modprobe -l

AnswerC

Lsmod shows currently loaded kernel modules from /proc/modules.

Why this answer

The correct option is B: lsmod lists loaded modules. Option A (modprobe -l) lists available modules, not loaded. Option C (modinfo) shows information about a specific module.

Option D (insmod) loads a module.

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MCQmedium

Refer to the exhibit. The system has a single disk with three partitions. Which partition contains the root filesystem?

A.sda

B.sda1

C.sda2

D.sda3

AnswerD

sda3 is mounted at / (root).

Why this answer

The root filesystem is mounted from the partition that contains the / (root) directory. In Linux, partitions are numbered starting from 1 (e.g., sda1, sda2, sda3). The device sda itself refers to the entire disk, not a partition.

Since the system has three partitions and the correct answer is sda3, partition sda3 must be the one designated as the root filesystem, typically identified by the mount point '/' in /etc/fstab or by the kernel boot parameter root=.

Exam trap

The trap here is that candidates often confuse the entire disk device (sda) with a partition (sda1, sda2, sda3), or assume the root filesystem is always on the first partition (sda1), ignoring that it can be on any numbered partition based on system design.

How to eliminate wrong answers

Option A is wrong because sda refers to the entire disk device, not a partition; the root filesystem must reside on a partition, not the raw disk. Option B is wrong because sda1 is a partition, but it is typically used for /boot or swap, not the root filesystem, unless explicitly configured; the question indicates sda3 is correct, so sda1 is not the root. Option C is wrong because sda2 is a partition, but it is often used for swap or extended partitions, and the correct answer is sda3, meaning sda2 does not contain the root filesystem in this scenario.

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MCQmedium

An administrator is migrating a legacy service from a SysV init system to a systemd unit. The service is a long-running daemon that forks once. The admin writes a unit file of Type=forking, sets PIDFile correctly, and enables the service. On the next reboot, the service starts but systemd reports that the service entered 'failed' state shortly after start, even though the process is running. The log shows: 'PID file /var/run/myservice.pid not readable (yet?) after start.' What is the most likely cause? Options: A) The service does not write its PID file quickly enough, B) The PIDFile path is wrong, C) The unit file should use Type=simple instead, D) The service needs a TimeoutStartSec increase.

A.The PIDFile path is wrong

B.The service does not write its PID file quickly enough

C.The service needs a TimeoutStartSec increase

D.The unit file should use Type=simple instead

AnswerB

Systemd expects the PID file shortly after the forking process exits; a delay causes failure.

Why this answer

Option A is correct: systemd waits for the PID file to appear after the forking process exits. If the daemon writes the PID file after a delay, systemd may time out. Option B is unlikely because the error mentions the file not readable, not missing.

Option C (simple) would not expect a PID file but would track the main process directly. Option D may help but the core issue is timing of PID file creation. Usually, increasing TimeoutStartSec is a workaround; the real fix is ensuring the daemon writes PID file early.

So A is most direct.

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MCQeasy

Which directory contains the kernel modules for the currently running kernel?

A./boot

B./etc/modprobe.d

C./usr/src

D./lib/modules/$(uname -r)

AnswerD

Standard location for kernel modules.

Why this answer

Option B is correct: the modules are stored under /lib/modules/ with the kernel version. Option A contains kernel images, C source code, D module configuration.

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MCQhard

An administrator needs to ensure that a specific kernel module is loaded automatically at boot. Which file should be used to permanently load the module?

A./etc/modprobe.d/modules.conf

B./etc/sysconfig/modules

C./etc/modules

D./etc/conf.modules

AnswerC

Modules listed in /etc/modules are loaded at boot.

Why this answer

Option C is correct because on modern Linux systems using a standard init system, the file /etc/modules (or /etc/modules-load.d/*.conf on systemd-based distributions) is read at boot to load specified kernel modules automatically. This file lists module names one per line, and the kernel's module loading mechanism processes it early in the boot sequence to ensure the module is available before services that depend on it start.

Exam trap

The trap here is that candidates confuse the configuration file for module options (/etc/modprobe.d/*.conf) with the file that lists modules to load at boot (/etc/modules), or they mistakenly recall the obsolete /etc/conf.modules from older Linux distributions.

How to eliminate wrong answers

Option A is wrong because /etc/modprobe.d/modules.conf is not a standard file; the correct directory is /etc/modprobe.d/ where files like *.conf are used for modprobe configuration (e.g., aliases, options, blacklists), not for specifying modules to load at boot. Option B is wrong because /etc/sysconfig/modules is not a standard path; on Red Hat-based systems, /etc/sysconfig/modules/ is a directory for custom module-loading scripts, but the primary mechanism for permanent module loading is /etc/modules or /etc/modules-load.d/. Option D is wrong because /etc/conf.modules is an obsolete file from older kernel versions (pre-2.6) and is not used by modern modprobe or systemd; it has been replaced by /etc/modprobe.d/ and /etc/modules.

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MCQeasy

A technician needs to output only the kernel release number. Which command should be used?

A.cat /proc/version

B.uname -r

C.dmesg | head -1

D.lsmod

AnswerB

uname -r outputs the exact kernel release number.

Why this answer

The `uname -r` command specifically prints the kernel release number (e.g., '5.10.0-28-amd64') by querying the `utsname` system call. This is the standard, portable way to retrieve only the kernel release string without additional system information.

Exam trap

The trap here is that candidates confuse `/proc/version` (which shows the full version string) with a command that outputs only the release number, or they assume `dmesg` output is consistent across all systems.

How to eliminate wrong answers

Option A is wrong because `cat /proc/version` outputs the full version string including the kernel release, compiler version, and build timestamp, not just the release number. Option C is wrong because `dmesg | head -1` shows the first line of the kernel ring buffer, which typically includes the kernel version and build info but is not guaranteed to be just the release number and may vary by system or boot. Option D is wrong because `lsmod` lists loaded kernel modules, not the kernel release number.

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MCQmedium

A server with a udev rule fails to consistently assign a persistent network interface name. What is the most likely cause?

A.The rule uses an incorrect operator.

B.The BIOS device name is configured incorrectly.

C.The kernel module for the NIC is not loaded.

D.The network interface's MAC address is not unique or changes.

AnswerD

If the MAC address changes, a rule matching by MAC will fail.

Why this answer

Persistent network interface names in Linux rely on udev rules that match attributes like MAC address. If the MAC address is not unique (e.g., due to a virtual machine or cloned NIC) or changes (e.g., after hardware replacement or driver update), the rule will fail to consistently identify the interface, causing the name assignment to be unpredictable.

Exam trap

The trap here is that candidates assume udev rules always work if the syntax is correct, overlooking that dynamic or non-unique MAC addresses undermine the stability of the matching attribute.

How to eliminate wrong answers

Option A is wrong because an incorrect operator (e.g., using '==' instead of '!=') would cause a syntax error or mis-match, but the question describes inconsistent assignment, not a complete failure; the rule still runs but the matching attribute is unreliable. Option B is wrong because BIOS device names (like 'eno1') are a naming scheme, not a cause of udev rule failure; incorrect BIOS configuration might affect the name format but does not prevent consistent assignment if the rule uses a stable attribute. Option C is wrong because if the kernel module for the NIC were not loaded, the interface would not appear at all, leading to a persistent failure rather than inconsistent naming.

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MCQmedium

An administrator runs 'lsmod' and sees a module with a usage count of 1. What does this indicate?

A.The module is loaded but not used by any process

B.The module is being used by one other module

C.One process is holding a reference to the module

D.The module has one dependency

AnswerC

The usage count indicates the number of active references.

Why this answer

Option C is correct: usage count shows the number of references to the module, often from a process or another module. Option A is false because count >0 means it is used. Option B is not necessarily true; it could be a process.

Option D is incorrect; dependencies are tracked separately.

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Multi-Selectmedium

Which THREE of the following are valid systemd targets?

Select 3 answers

A.poweroff.target

B.rescue.target

C.reboot.target

D.halt.target

E.shutdown.target

AnswersA, B, C

Standard target for system poweroff.

Why this answer

Correct: A, B, E. poweroff.target, reboot.target, and rescue.target are standard systemd targets. Option C 'halt.target' is not a valid systemd target (halt is performed via a different mechanism); D 'shutdown.target' is also not standard.

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MCQeasy

During boot, the kernel must mount the root filesystem. Which of the following is responsible for providing the kernel with the location of the root filesystem?

A.udev

B.initramfs

C.init

D.boot loader

AnswerD

The boot loader passes root= parameter to the kernel.

Why this answer

The boot loader (e.g., GRUB) is responsible for loading the kernel into memory and passing it the location of the root filesystem via kernel command-line parameters such as `root=`. Without this parameter, the kernel would not know which block device or partition to mount as `/`. The boot loader reads configuration files (e.g., `grub.cfg`) that specify this parameter, making it the direct provider of the root filesystem location.

Exam trap

The trap here is that candidates often confuse initramfs as the provider of the root filesystem location, when in fact initramfs is a tool that uses the location provided by the boot loader to mount the real root filesystem.

How to eliminate wrong answers

Option A is wrong because udev is a device manager that runs in userspace after the root filesystem is mounted; it handles device node creation and hotplug events, not kernel boot parameters. Option B is wrong because initramfs is a temporary root filesystem loaded by the boot loader that contains tools and drivers to mount the real root filesystem, but it does not itself provide the location; it relies on the `root=` parameter passed by the boot loader. Option C is wrong because init is the first userspace process (PID 1) started after the root filesystem is mounted; it manages services and system initialization, not the kernel's boot-time root filesystem location.

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Multi-Selecteasy

Which TWO commands can be used to obtain information about the CPU architecture of a Linux system?

Select 2 answers

A.uname -m

B.lscpu

C.dmidecode -t processor

D.cat /proc/cpuinfo

E.lspci

AnswersB, D

Displays CPU architecture details including cores, threads, model name, etc.

Why this answer

lscpu displays CPU architecture info from /proc/cpuinfo and sysfs. cat /proc/cpuinfo directly shows CPU details. lspci lists PCI devices, dmidecode shows DMI data (not CPU specifics), uname -m shows machine architecture but not detailed CPU info. Correct are A and B.

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MCQhard

A system has multiple CPUs but only one is being used. Which file under /sys/ can be checked to verify CPU online status?

A./sys/devices/system/cpu/online

B./proc/cpuinfo

C./sys/class/cpu

D./sys/devices/system/cpu/cpu0/online

AnswerD

Contains a 1 if online, 0 if offline for CPU0.

Why this answer

Option A is correct: each CPU has its own 'online' file. Option B is a summary of online CPUs, but the individual file gives per-CPU status. Option C is /proc/cpuinfo which shows overall info but not online status dynamically.

Option D does not exist.

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MCQmedium

A system administrator needs to create a new Logical Volume (LV) in an existing LVM setup. Which sequence of commands is correct?

A.vgcreate, pvcreate, lvcreate

B.pvcreate, vgcreate, lvcreate

C.pvcreate, lvcreate, vgcreate

D.lvcreate, vgcreate, pvcreate

AnswerB

Correct order: PV first, then VG, then LV.

Why this answer

Correct: A. The proper order is: pvcreate (create Physical Volume), vgcreate (create Volume Group), lvcreate (create Logical Volume). Options B, C, D are incorrect because they either start with LV or miss steps.

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MCQhard

Refer to the exhibit. A Linux system fails to boot with a kernel panic. The dmesg output shows the disk is detected and partitions are recognized. Which of the following is the most likely cause of the kernel panic?

A.The root filesystem cannot be mounted because the root= kernel parameter points to a non-existent or incorrect device.

B.The kernel module for the SATA controller is missing from the initramfs.

C.The SATA controller is not supported by the kernel.

D.The disk has bad sectors causing read errors during boot.

AnswerA

The kernel detects the disk and partitions but then panics, likely because it cannot mount the root filesystem, often due to an incorrect root= parameter.

Why this answer

A is correct because the kernel panic occurs after the disk and partitions are detected, indicating the kernel can see the hardware but cannot mount the root filesystem. The most common cause is an incorrect or missing `root=` kernel parameter in the bootloader configuration (e.g., GRUB), which specifies the root device (e.g., `/dev/sda1` or `UUID=...`). If this parameter points to a non-existent or wrong partition, the kernel cannot pivot to the root filesystem, leading to a panic.

Exam trap

The trap here is that candidates see the disk is detected and assume hardware is fine, then incorrectly blame the SATA controller or initramfs, missing the subtle point that the kernel panic occurs specifically because the root filesystem cannot be mounted due to a misconfigured `root=` parameter.

How to eliminate wrong answers

Option B is wrong because if the SATA controller module were missing from the initramfs, the disk would not be detected at all, but the dmesg output shows the disk is detected and partitions are recognized. Option C is wrong because the SATA controller is clearly supported by the kernel, as the disk is detected and partitions are recognized, contradicting a lack of support. Option D is wrong because bad sectors causing read errors would typically produce I/O errors or filesystem corruption messages, not a kernel panic at the stage where the root filesystem cannot be mounted; the panic occurs before any filesystem read attempts.

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MCQeasy

A Linux system fails to boot after installing a new kernel. Which step should be taken first to recover the system?

A.Edit GRUB configuration at boot to select the old kernel

B.Reinstall the original kernel using a live CD

C.Boot into single-user mode to fix the kernel

D.Use the rescue mode from installation media

AnswerA

At GRUB menu, press 'e' to edit and change the kernel line to the old kernel.

Why this answer

Option D is correct because you can interrupt GRUB at boot by pressing Shift or Esc to access the boot menu, then edit the boot entry to select the previous kernel. Option A is too drastic; B is possible but not first; C is a last resort.

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MCQeasy

What is stored in the first sector of a hard disk (Master Boot Record)?

A.The Master Boot Record (boot loader and partition table)

B.The partition table only

C.The Linux kernel

D.The root filesystem

AnswerA

The MBR contains boot loader code and partition table.

Why this answer

Correct: B. The Master Boot Record (MBR) contains the boot loader code and partition table for the disk. Option A is incorrect because the partition table is part of the MBR but not the only element; C and D are stored on filesystems or in the kernel.

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MCQhard

A system takes a long time to boot due to a service that fails to start. Which systemd command can be used to identify the service causing the delay?

A.journalctl -u service

B.systemctl status

C.systemd-analyze critical-chain

D.systemd-analyze blame

AnswerD

Lists services with their initialization time, sorted by longest.

Why this answer

Option A is correct: 'systemd-analyze blame' lists services with their startup times, helping identify slow ones. Option D shows critical chain but not individual times. Options B and C show status and logs but not timing.

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MCQeasy

Which command displays information about the CPU, including model name, cache size, and flags?

A.uname -a

B.lscpu

C.cat /proc/cpuinfo

D.dmidecode

AnswerB

lscpu displays CPU architecture information from /proc/cpuinfo.

Why this answer

The `lscpu` command is the correct choice because it is specifically designed to display CPU architecture information, including model name, cache sizes, and flags (such as SSE, AES, etc.), by reading data from sysfs and /proc/cpuinfo in a human-readable format. It provides a concise summary without requiring root privileges, making it the most appropriate tool for this task.

Exam trap

The trap here is that candidates often choose `cat /proc/cpuinfo` because it contains all the raw data, but the exam expects the command that is specifically designed to present CPU information in a readable summary, which is `lscpu`.

How to eliminate wrong answers

Option A is wrong because `uname -a` displays system kernel information (e.g., kernel name, hostname, kernel release, architecture), but it does not show CPU model name, cache size, or flags. Option C is wrong because while `cat /proc/cpuinfo` does contain all the requested CPU details, it outputs raw, verbose data that is not formatted for quick reading; the question asks for a command that 'displays information' in a practical sense, and `lscpu` is the standard utility for this purpose. Option D is wrong because `dmidecode` reads DMI/SMBIOS tables to provide hardware information (e.g., BIOS, motherboard, memory), but it requires root privileges and does not directly output CPU flags or cache details in a straightforward manner.

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MCQhard

A Linux system with a custom kernel fails to boot after a new kernel is compiled and installed. The boot process stops at a prompt: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. The root filesystem is on /dev/sda2 with ext4. The system has an initramfs generated with dracut. The admin can boot from a previous kernel. Which is the most appropriate next step to troubleshoot and fix the issue? Options: A) Rebuild the initramfs using 'dracut --force --kver' with the correct kernel version, B) Add 'root=/dev/sda2' to the kernel command line, C) Use 'mkinitrd' with the '--preload' option for ext4 module, D) Run 'ldd /sbin/init' to check for missing libraries.

A.Run 'ldd /sbin/init' to check for missing libraries

B.Rebuild the initramfs using 'dracut --force --kver' with the correct kernel version

C.Use 'mkinitrd' with the '--preload' option for ext4 module

D.Add 'root=/dev/sda2' to the kernel command line

AnswerB

Regenerates the initramfs ensuring all necessary modules are included.

Why this answer

Option A is correct because the initramfs may be missing necessary drivers for the root filesystem or controller. Regenerating it with dracut for the new kernel ensures modules are included. Option B is likely already present (the error says unknown-block, indicating root= parameter might be missing or wrong, but if it's in GRUB, it should be there).

Option C uses mkinitrd which is deprecated on newer systems with dracut. Option D is for user-space issues; the panic is at boot before init runs. So A is best.

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MCQhard

A company runs a critical database server on Linux. The server has a hardware RAID controller with two logical volumes: one for the operating system (LV1) and one for the database data (LV2). The server uses LVM on top of the RAID volumes. Recently, the database performance has degraded. The administrator suspects that the file system on LV2 is heavily fragmented. The server uses the ext4 filesystem. The administrator wants to check the fragmentation level and, if necessary, defragment the filesystem without unmounting it or causing downtime. However, ext4 does not support online defragmentation. What should the administrator do to minimize fragmentation impact while maintaining availability?

A.Create a new filesystem on LV2, copy data back, and symlink the old mount point to the new one.

B.Use tune2fs to set the reserved block percentage to 0 and increase the inode size.

C.Schedule a maintenance window, unmount LV2, run e2fsck -fn, then run e2fsck -D to defragment.

D.Use the e4defrag command with the -v option on the mount point to check and defragment files online.

AnswerD

e4defrag can defragment files on a mounted ext4 filesystem, reducing fragmentation without downtime.

Why this answer

Option D is correct because e4defrag is a tool specifically designed for online defragmentation of ext4 filesystems. It can check fragmentation levels and defragment files without requiring the filesystem to be unmounted, thus avoiding downtime. This directly addresses the administrator's need to minimize fragmentation impact while maintaining availability.

Exam trap

The trap here is that candidates may assume ext4 has no online defragmentation support at all, but e4defrag provides a limited online capability, or they may confuse e4defrag with e2fsck, which requires unmounting.

How to eliminate wrong answers

Option A is wrong because creating a new filesystem and copying data back requires unmounting LV2 or at least remounting it, causing downtime, and symlinking does not solve fragmentation on the original filesystem. Option B is wrong because tune2fs adjusts filesystem parameters like reserved blocks and inode size, but it does not perform defragmentation or check fragmentation levels. Option C is wrong because while e2fsck -D can defragment directories, it requires the filesystem to be unmounted, causing downtime, and the -fn option is for a read-only check, not defragmentation.

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MCQhard

A system administrator is responsible for a Linux server running a critical application. The server recently experienced an unplanned power outage. Upon rebooting, the system fails to reach the default target and drops into an emergency shell. The administrator notices that the root filesystem (/) is mounted read-only. The /etc/fstab file contains the following lines: UUID=abc123 / ext4 errors=remount-ro 0 1 UUID=def456 /home ext4 defaults 0 2 UUID=ghi789 none swap sw 0 0 The administrator suspects that the /home filesystem has a corrupt superblock and is causing the boot failure. The administrator needs to check and repair the /home filesystem without causing data loss. Which of the following is the correct course of action?

A.Reinstall the system from backup because the superblock corruption is fatal.

B.Boot from a live USB, run 'fsck /dev/sdb1' on the unmounted filesystem, then reboot.

C.Run 'fsck /dev/sdb1' from the emergency shell after remounting /home read-write.

D.Run 'fsck -y /dev/sdb1' from the emergency shell, but first run 'mount -o remount,rw /home' to make the filesystem writable.

AnswerB

Using a live environment ensures the filesystem is unmounted, allowing safe repair.

Why this answer

The correct option is C: Boot from a live USB and run fsck on the unmounted filesystem. This ensures the filesystem is not mounted, preventing further corruption. Option A attempts to run fsck on a mounted filesystem, which can cause data loss.

Option B attempts to mount the corrupt filesystem read-write before checking, which may worsen the corruption. Option D is overly drastic and unnecessary; a corrupted superblock can often be repaired with fsck using an alternate superblock.

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Multi-Selectmedium

Which TWO of the following are required for a system to boot using UEFI?

Select 2 answers

A.The bootloader installed in the ESP

B.An EFI System Partition (ESP) formatted with FAT32

C.The bootloader installed in the Master Boot Record (MBR)

D.A BIOS boot partition

E.A kernel with EFI stub support

AnswersA, B

The bootloader (e.g., GRUB) must be installed in the ESP for UEFI to find it.

Why this answer

Correct options are A and C. An EFI System Partition (ESP) formatted with FAT32 is mandatory, and the bootloader (e.g., GRUB) must be installed in the ESP. Option B (BIOS boot partition) is used for GRUB on BIOS systems, not UEFI.

Option D (bootloader in MBR) is for BIOS. Option E (kernel with EFI stub support) is optional; bootloaders can invoke kernels without EFI stub.

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Multi-Selectmedium

Which TWO statements about GRUB 2 are correct?

Select 2 answers

A.After modifying /etc/default/grub, the command update-grub must be run to regenerate grub.cfg.

B.The GRUB configuration file read at boot is /boot/grub/grub.cfg.

C.GRUB 2 uses a configuration file named menu.lst.

D.The GRUB prompt can be accessed by pressing the 'e' key during boot.

E.The /etc/default/grub file is directly read by GRUB during boot.

AnswersA, B

update-grub (or grub-mkconfig) regenerates grub.cfg based on settings in /etc/default/grub.

Why this answer

Option A is correct because GRUB 2 reads the configuration file /boot/grub/grub.cfg at boot. Option C is correct because after editing /etc/default/grub, the update-grub command must be run to regenerate grub.cfg. Option B is incorrect because /etc/default/grub is not read by GRUB at boot; it is used by update-grub.

Option D is incorrect because menu.lst is used by GRUB Legacy, not GRUB 2. Option E is incorrect because pressing 'e' at the GRUB menu edits the boot entry, but the GRUB prompt is accessed by pressing 'c'.

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MCQhard

Refer to the exhibit. The system is unable to mount a filesystem that should be identified by UUID 1234-5678. The administrator checks /etc/fstab and finds the entry: UUID=1234-5678 /data ext4 defaults 0 2. What is the most likely cause of the mount failure?

A.The /data mount point does not exist.

B.The device /dev/sda1 is not formatted with ext4.

C.The UUID in the fstab entry is incorrect.

D.The symlink for UUID 1234-5678 is broken.

AnswerD

The symlink exists but the target /dev/sda1 may not exist, causing a broken link and mount failure.

Why this answer

The symlink for UUID 1234-5678 points to ../../sda1. If the device /dev/sda1 does not exist (e.g., removed or not probed), the symlink is broken and mount fails. The UUID itself appears correct, and the fstab entry looks valid.

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Multi-Selectmedium

Which THREE of the following are valid systemd service unit types?

Select 3 answers

A.oneshot

B.simple

C.runtime

D.exec

E.forking

AnswersA, B, E

A service that runs a command and exits; often used for setup scripts.

Why this answer

Systemd service units can be of types: simple, forking, oneshot, dbus, notify, idle. For correct options, 'forking' is a type (service starts a child process and exits), 'simple' (main process is started directly), 'oneshot' (executes and then exits). 'exec' is not a service type; 'idle' is a type but not listed; 'runtime' is not a type. So correct are A, B, D.

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MCQeasy

Which systemd target corresponds to the traditional runlevel 3?

A.multi-user.target

B.graphical.target

C.emergency.target

D.rescue.target

AnswerA

Multi-user.target is the standard text mode, equivalent to runlevel 3.

Why this answer

The correct option is C: multi-user.target corresponds to runlevel 3 (multi-user text mode). Option A (graphical.target) is runlevel 5. Option B (rescue.target) is runlevel 1.

Option D (emergency.target) is a more minimal state.

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MCQmedium

A system administrator wants to disable the graphical target and boot to the text mode multi-user.target permanently. Which command should they run?

A.systemctl enable multi-user.target

B.systemctl isolate multi-user.target

C.systemctl set-default multi-user.target

D.systemctl default multi-user.target

AnswerC

This sets the default target for future boots.

Why this answer

systemctl set-default multi-user.target changes the default target permanently, so the system will boot to multi-user mode (text) instead of graphical.target.

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MCQmedium

A Linux system fails to boot with the error: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. What is the most likely cause?

A.Missing root filesystem

B.Corrupt kernel image

C.Damaged bootloader

D.Missing or incorrect initrd

AnswerD

Initrd contains drivers needed to mount root filesystem.

Why this answer

Correct: C. This error typically indicates that the initrd (initial ramdisk) is missing or does not contain the necessary drivers to mount the root filesystem. Option A (missing root filesystem) would produce a different error; B (corrupt kernel) would show earlier issues; D (damaged bootloader) would prevent kernel loading.

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MCQhard

A system has a software RAID1 array (/dev/md0) with two disks: /dev/sda and /dev/sdb. Disk /dev/sda fails. Which command sequence will replace the failed disk with a new /dev/sdc without stopping the array?

A.mdadm --stop /dev/md0; replace disk; mdadm --assemble /dev/md0 /dev/sdb /dev/sdc

B.mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda && mdadm --manage /dev/md0 --add /dev/sdc

C.Shutdown system, physically replace disk, reboot

D.dd if=/dev/sdb of=/dev/sdc bs=64K

AnswerB

Correct sequence: fail, remove, then add new disk.

Why this answer

Correct: A. The mdadm commands '--fail' marks the disk as failed, '--remove' removes it, then '--add' adds the new disk. Option B stops the array which is unnecessary; C (dd) is not appropriate for live replacement; D requires reboot which is not ideal.

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MCQmedium

A system administrator needs to ensure that the httpd service starts automatically when the system enters the multi-user.target. Which command should be used?

A.systemctl add-wants multi-user.target httpd.service

B.systemctl enable httpd

C.systemctl start httpd

D.systemctl set-default multi-user.target

AnswerB

Enables the service to start automatically on boot for the current default target.

Why this answer

systemctl enable httpd creates symlinks so the service starts at boot when the target includes it. The default target for multi-user is typically multi-user.target.

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MCQmedium

A system administrator notices that the server's clock is consistently off by several minutes. Which service should be used to synchronize the time with an external time source?

A.ntpd

B.timed

C.chronyd

D.systemd-timesyncd

AnswerA

ntpd is the standard NTP daemon for time synchronization.

Why this answer

The Network Time Protocol (NTP) daemon (ntpd) is the traditional and widely used service for synchronizing a server's clock with an external time source. It continuously adjusts the system time by communicating with NTP servers, compensating for clock drift and network delays to maintain accurate time. This makes ntpd the correct choice for resolving a consistent clock offset of several minutes.

Exam trap

The trap here is that candidates may confuse chronyd (a modern alternative) with ntpd, but LPIC-1 traditionally expects ntpd as the standard answer for time synchronization, even though chronyd is also correct in practice—the exam tests knowledge of the classic service name.

How to eliminate wrong answers

Option B (timed) is wrong because 'timed' is not a standard Linux time synchronization service; it is a legacy BSD tool for time synchronization and is not used in modern Linux distributions. Option C (chronyd) is wrong because although chronyd is a valid NTP client and server (part of the chrony suite) and can synchronize time, it is not the service named in the question's context—the question specifically asks for the service that should be used, and ntpd is the classic, expected answer for LPIC-1. Option D (systemd-timesyncd) is wrong because it is a lightweight SNTP client that only performs periodic time corrections and lacks the full NTP protocol capabilities (e.g., it cannot act as a time server or handle large clock offsets as effectively as ntpd), making it unsuitable for consistently correcting a several-minute offset.

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Multi-Selecteasy

Which TWO of the following are valid methods to change the default runlevel on a SysV init-based system?

Select 2 answers

A.Use the 'runlevel' command to set the default runlevel.

B.Edit /etc/inittab to set the initdefault line.

C.Pass the desired runlevel as a kernel parameter at boot time.

D.Use 'systemctl set-default' to set the default runlevel.

E.Use the 'telinit' command to change the default runlevel.

AnswersB, C

The initdefault line in /etc/inittab defines the default runlevel.

Why this answer

In SysV init-based systems, the default runlevel is defined in the /etc/inittab file by the 'initdefault' line, which specifies the runlevel the system should enter after boot. Editing this line is the standard method to permanently change the default runlevel. Option B correctly identifies this mechanism.

Exam trap

The trap here is that candidates confuse the 'runlevel' command (which only displays) with a command that can set the default, or they mistakenly apply systemd commands like 'systemctl set-default' to SysV init systems.

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Matchingmedium

Match each ACL term to its meaning.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Permissions for a specific user

Permissions for a specific group

Maximum permissions for named users and groups

Permissions for everyone else

Inherited ACL for new files/directories

Why these pairings

Access Control List (ACL) entries.

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MCQmedium

To add a kernel parameter temporarily to the kernel command line at boot, what key should be pressed in the GRUB menu?

A.e

B.b

C.r

D.c

AnswerA

Press 'e' to edit the selected boot entry.

Why this answer

Option A is correct: pressing 'e' allows editing the current boot entry. Option C boots immediately, B opens GRUB shell, D is not a standard key.

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MCQmedium

A system administrator needs to see the boot messages recorded by systemd-journald from the current boot. Which command is most appropriate?

A.journalctl -b

B.dmesg

C.tail -n 50 /var/log/syslog

D.cat /var/log/messages

AnswerA

Correctly shows all log entries from the current boot, including boot-time messages.

Why this answer

journalctl -b filters the journal to show messages from the current boot. This includes boot messages recorded by systemd-journald.

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Drag & Dropmedium

Arrange the steps to configure a firewall rule using iptables to allow SSH.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

Why this order

iptables rules are added, then saved to a file, and persistence ensures they survive reboot.

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MCQhard

During boot, a sysadmin sees the message 'Buffer I/O error on device sda1, logical block 0'. What does this most likely indicate?

A.Incorrect partition table

B.Filesystem corruption

C.Bad sector on the disk

D.Missing kernel module for the device

AnswerC

I/O error on a specific block suggests hardware failure.

Why this answer

Correct: B. A buffer I/O error on a specific logical block typically indicates a physical disk problem, such as a bad sector. Option A (filesystem corruption) might show different errors; C (missing driver) would prevent detection; D (incorrect partition table) would show partition errors.

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MCQmedium

A system administrator notices that a server with a freshly installed Linux system fails to boot with the error 'No bootable device found'. The server has a single SATA hard disk connected to the motherboard's SATA controller. Which of the following is the most likely cause of this issue?

A.The root filesystem is formatted with an unsupported filesystem type.

B.The kernel module for the SATA controller is not included in the initramfs.

C.The GRUB bootloader configuration file is missing or corrupted.

D.The BIOS boot order is set to a device that does not contain a bootable operating system.

AnswerD

The BIOS attempts to boot from a device that lacks a bootloader, resulting in the error.

Why this answer

The error 'No bootable device found' occurs during the BIOS/UEFI POST phase, before any bootloader is loaded. This indicates that the system firmware cannot find a valid boot sector on any device in its boot order. Since the server has a single SATA hard disk, the most likely cause is that the BIOS boot order is set to a different device (e.g., a network boot or removable media) that does not contain a bootable operating system, or the hard disk itself is not listed first in the boot priority.

Exam trap

The trap here is that candidates often confuse a pre-boot firmware error with a bootloader or kernel issue, leading them to incorrectly select options related to GRUB configuration or initramfs modules, when the actual problem is a simple BIOS boot order misconfiguration.

How to eliminate wrong answers

Option A is wrong because an unsupported root filesystem type would cause a kernel panic or mount failure during the boot process, not a 'No bootable device found' error, which occurs before the kernel is loaded. Option B is wrong because a missing SATA controller kernel module in the initramfs would result in a kernel panic or inability to mount the root filesystem after the bootloader loads, not a pre-boot firmware error. Option C is wrong because a missing or corrupted GRUB configuration file would cause GRUB to drop to a rescue shell or display a GRUB-specific error, not a 'No bootable device found' message, which is issued by the BIOS/UEFI before any bootloader is executed.

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