LPIC-1 System Architecture Practice Test 7 — 15 Questions

Question 1

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?

Accepted Answer

udevadm trigger. The correct command is `udevadm trigger`. This command causes udev to re-evaluate all devices by simulating kernel uevents, which forces udev to process rules and create device nodes in /dev for devices that were missed or not properly initialized.

Answer

modprobe

Answer

udevadm control --reload

Answer

udevadm settle

Question 2

Which command displays information about currently loaded kernel modules?

Accepted Answer

lsmod. The `lsmod` command reads the `/proc/modules` file to display a list of all currently loaded kernel modules, showing their name, size, usage count, and dependent modules. This is the standard tool for querying the current module state in the Linux kernel.

Answer

insmod

Answer

modinfo

Answer

modprobe -l

Question 3

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

Accepted Answer

journalctl -k. Option B (journalctl -k) is correct because on systemd-based systems the journal stores kernel messages, and the -k (or --dmesg) flag filters the journal to show only kernel-ring-buffer entries, making it a native systemd method to view kernel messages. Option E (dmesg) is correct because it directly reads and prints the kernel ring buffer, which contains kernel boot and runtime messages, and it remains valid on systemd systems. Option A (lsmod) is not correct because it only lists currently loaded kernel modules and does not display kernel log messages. Option C (cat /var/log/syslog) is not correct as a systemd-specific kernel-message method because syslog files are produced by a syslog daemon (and may not even exist on all systemd systems), not by systemd's journal, so it is not a reliable systemd-based way to view kernel messages. Option D (grub-mkconfig) is not correct because it generates GRUB bootloader configuration and has nothing to do with viewing kernel messages.

Answer

lsmod

Answer

cat /var/log/syslog

Answer

grub-mkconfig

Question 4

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

Accepted Answer

The bootloader installed in the ESP. Option B is correct because UEFI firmware requires an EFI System Partition (ESP) formatted with FAT32 (or FAT16 on removable media) to store and load EFI boot applications. Option A is correct because the bootloader must be installed as an EFI application within the ESP (e.g., \EFI\BOOT\BOOTX64.EFI or a vendor path) for the firmware to locate and execute it. Option C is incorrect because the MBR boot code is a legacy BIOS mechanism, not used by UEFI. Option D is incorrect because a BIOS boot partition is a GPT partition used by GRUB in BIOS/GPT setups, not by UEFI. Option E is incorrect because EFI stub support is optional; UEFI can boot via a separate bootloader such as GRUB or systemd-boot without a kernel EFI stub.

Answer

The bootloader installed in the Master Boot Record (MBR)

Answer

A BIOS boot partition

Answer

A kernel with EFI stub support

Question 5

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?

Accepted Answer

mkswap /dev/sdb2. The `mkswap` command is specifically designed to initialize a partition or file as a swap area by writing a swap signature (UUID and swap superblock) to the device. After creating the partition, you must run `mkswap /dev/sdb2` to set it up for use as swap before activating it with `swapon`.

Answer

mkfs.ext4 /dev/sdb2

Answer

fsck /dev/sdb2

Answer

swapon /dev/sdb2

Question 6

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

Accepted Answer

systemctl enable sshd.service. The `systemctl enable sshd.service` command creates the necessary symlinks in the systemd unit configuration directories (e.g., `/etc/systemd/system/multi-user.target.wants/`) so that the sshd service is automatically started when the system boots into its default target. This is the correct way to enable a service to start at boot in a systemd-based Linux distribution.

Answer

systemctl start sshd.service

Answer

systemctl daemon-reload

Answer

systemctl set-default multi-user.target

Question 7

A system administrator suspects a failing power supply because the server randomly reboots. Which command can be used to check hardware health and event logs?

Accepted Answer

ipmitool sensor list. The `ipmitool sensor list` command queries the Baseboard Management Controller (BMC) via the IPMI protocol to retrieve real-time sensor readings (e.g., voltages, temperatures, fan speeds) and system event logs (SEL). This is the correct tool for diagnosing hardware-level issues like a failing power supply, as it provides direct access to the server's hardware health monitoring subsystem, independent of the operating system.

Answer

sensors -u

Answer

lspci -v

Answer

dmidecode -t baseboard

Question 8

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?

Accepted Answer

Boot from a live CD, chroot, and run 'update-initramfs -u -k all' to regenerate the initramfs with lvm2 support. The error 'Failed to mount the real root device' after a system upgrade indicates the initramfs lacks the necessary LVM modules (e.g., lvm2) to activate and mount the root logical volume. Regenerating the initramfs with 'update-initramfs -u -k all' rebuilds it to include LVM support, ensuring the kernel can locate and mount the root filesystem during boot.

Answer

Run 'lvchange -ay' to activate all LVs

Answer

Reinstall GRUB to the MBR

Answer

Use 'fsck' on the root LV

Question 9

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) Use ifenslave directly after ifup, C) Reboot the system to load the module, D) Add 'auto bond0' in /etc/network/interfaces.

Accepted Answer

Run 'modprobe bonding' before ifup. The 'bond' kernel module must be loaded before the bonding interface can be created. Running 'modprobe bonding' loads the module into the kernel, making the bonding functionality available. Without this step, 'ifup bond0' fails because the kernel does not recognize the bonding driver.

Answer

Use ifenslave directly after ifup

Answer

Reboot the system to load the module

Answer

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

Question 10

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.

Accepted Answer

Run 'timedatectl set-ntp true' to enable systemd-timesyncd. On Ubuntu 20.04, systemd-timesyncd is the default NTP client. Running 'timedatectl set-ntp true' (option A) activates it, which automatically synchronizes the system clock with NTP servers, correcting the gradual drift without needing additional packages or manual cron jobs. This is the simplest and most appropriate single action for automatic time sync on a modern systemd-based distribution.

Answer

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

Answer

Install and configure the ntp package with a pool server

Answer

Use 'cron' to run ntpdate every minute

Question 11

A data center server with two NICs (eth0 and eth1) is configured for network bonding in mode 1 (active-backup). The admin notices that after a cable pull on eth0, the bond interface fails over to eth1 as expected. However, when the cable is reconnected to eth0, the bond remains on eth1 indefinitely. The admin checks /proc/net/bonding/bond0 and sees that eth0 is marked as 'up' but not as 'active'. Which parameter is most likely missing from the bond configuration? Options: A) 'miimon=100' to enable link monitoring, B) 'downdelay=0', C) 'updelay=0', D) 'primary=eth0' to prefer eth0 as the active slave.

Accepted Answer

primary=eth0. The bond is in active-backup mode (mode 1) and eth0 is marked as 'up' but not 'active' after reconnection. Without the 'primary=eth0' parameter, the bond does not automatically switch back to the preferred slave (eth0) once it becomes available; it only fails over to eth1 when eth0 goes down. Setting 'primary=eth0' ensures that eth0 is always preferred as the active slave when it is in 'up' state, triggering a failback.

Answer

updelay=0

Answer

downdelay=0

Answer

miimon=100

Question 12

Which TWO statements about GRUB 2 are correct?

Accepted Answer

After modifying /etc/default/grub, the command update-grub must be run to regenerate grub.cfg.. Option A is correct because /etc/default/grub is a user-editable configuration file containing variables like GRUB_TIMEOUT and GRUB_CMDLINE_LINUX, and changes to it only take effect after running update-grub (a wrapper for grub-mkconfig) to regenerate the actual boot configuration. Option B is correct because GRUB 2 reads /boot/grub/grub.cfg at boot time, which is the generated file containing menu entries and boot directives. Option C is incorrect because menu.lst belongs to GRUB Legacy, not GRUB 2. Option D is incorrect because pressing 'e' at the GRUB menu opens an editor for the selected entry, not a GRUB command prompt; the 'c' key accesses the command-line prompt. Option E is incorrect because /etc/default/grub is not read directly by GRUB at boot; it is only consumed by grub-mkconfig/update-grub to produce grub.cfg.

Answer

GRUB 2 uses a configuration file named menu.lst.

Answer

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

Answer

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

Question 13

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?

Accepted Answer

dmesg | grep -i scsi. The `dmesg` command displays kernel ring buffer messages, which include hardware detection and initialization logs during boot. By piping to `grep -i scsi`, you filter for SCSI-related messages, revealing the order in which devices were discovered and any errors for undetected drives. This is the most direct way to see why a specific SAS drive failed to appear.

Answer

cat /proc/scsi/scsi

Answer

lsblk

Answer

lsscsi

Question 14

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?

Accepted Answer

Rebuild the initramfs to include the mdadm module and the RAID metadata.. After a kernel update, the new kernel may lack the necessary mdadm module or RAID metadata support in the initramfs. The error 'unknown-block(0,0)' indicates the kernel cannot find the root device because the initramfs does not contain the required RAID drivers or assembly instructions. Rebuilding the initramfs with the correct mdadm configuration ensures the kernel can assemble and mount /dev/md0 during boot.

Answer

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

Answer

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

Answer

Reinstall the bootloader on the MBR.

Question 15

A Linux server has two hot-swappable SATA drives that are part of a software RAID 1 array. The administrator needs to replace one drive while the system is running, but first wants to verify the current status of the array to ensure it is not degraded. Which command will display the detailed status of the mdadm array?

Accepted Answer

mdadm --detail /dev/md0. To verify the status of a software RAID array before replacing a drive, the administrator needs detailed information about the array's health and component devices. The mdadm --detail command provides this comprehensive view, including RAID level, state, and per-device status. This ensures the array is not already degraded and that the correct drive can be identified for replacement. Other commands either show only summary information or focus on physical drives rather than the RAID logical device.

Answer

cat /proc/mdstat

Answer

smartctl -a /dev/sda

Answer

fdisk -l /dev/sda