LPIC-2 Practice Test 21 — 15 Questions

Question 1

Refer to the exhibit. The user 'user' reports that they are able to run 'sudo apt-get update' without a password, but 'sudo apt-get upgrade' prompts for a password. What is the most likely cause?

Accepted Answer

The second rule does not include the NOPASSWD tag, so password is required.. The sudoers rule for 'apt-get upgrade' lacks the NOPASSWD tag, so sudo defaults to requiring a password. The first rule for 'apt-get update' includes NOPASSWD, which allows passwordless execution, but each command specification in sudoers is independent unless explicitly grouped. The absence of NOPASSWD on the second rule means sudo will prompt for the user's password as per its default behavior.

Answer

The 'Defaults:user !requiretty' setting affects password prompting.

Answer

The command 'apt-get upgrade' is being run as the user, not as root.

Answer

The rules are in the wrong order, causing the second to be overridden.

Question 2

Which command is used to list the NFS exports available from a specific server?

Accepted Answer

showmount -e server. The `showmount -e server` command queries the NFS server's mount daemon (rpc.mountd) to list the exported filesystems that are currently available. This is the standard method for a client to discover which NFS shares a server is offering, as it directly interrogates the server's export list via the RPC protocol.

Answer

mount -t nfs4 server:/export /mnt

Answer

nfsstat

Answer

exportfs -a

Question 3

A company delegates the subdomain lab.example.com to an internal BIND 9 server. The parent zone on the external authoritative server contains NS records for lab.example.com pointing to ns1.lab.example.com, plus a glue A record. Internal clients query the external resolver and receive the delegation, but queries for host1.lab.example.com time out. The internal server's named.conf contains a zone statement for lab.example.com with type master and a valid zone file. Which condition MOST likely explains the timeout?

Accepted Answer

The internal server is not configured to allow queries from the external resolver's address.. When a delegation exists and the child server is authoritative with a valid zone file, a timeout usually means the child never answers the querying resolver. Restrictive allow-query settings on the internal server silently drop queries from the external resolver's address, producing timeouts while the parent delegation itself still works.

Answer

The internal server's zone file uses an SOA serial number lower than the parent zone's serial.

Answer

The external authoritative server needs a forward zone for lab.example.com to answer child queries.

Answer

The glue A record for ns1.lab.example.com is missing from the parent zone.

Question 4

A server uses an initramfs image generated by dracut. After adding a new storage driver module, the administrator needs to ensure the module is included in the initramfs for the running kernel. Which command should be executed?

Accepted Answer

dracut -f /boot/initramfs-$(uname -r).img $(uname -r). On a dracut-based system, the initramfs is rebuilt with the dracut command. Using dracut -f with the kernel version and output path forces regeneration and includes newly added modules. Other tools like mkinitrd or update-initramfs are either legacy or distribution-specific and may not properly integrate with dracut configuration.

Answer

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

Answer

update-initramfs -u -k $(uname -r)

Answer

mkinitrd -f /boot/initramfs-$(uname -r).img $(uname -r)

Question 5

A system administrator wants to inspect which kernel modules are currently loaded into the running kernel, along with their sizes and dependencies. Which command provides this information by reading from /proc/modules?

Accepted Answer

lsmod. The lsmod command reads /proc/modules and prints a table of loaded modules with their sizes and usage counts. It is the correct tool for inspecting the current runtime state of kernel modules. Commands like modinfo and depmod work with module files on disk, while insmod is used to insert a module, not to list them.

Answer

modinfo

Answer

insmod

Answer

depmod

Question 6

A Debian-based production server was patched last night and now boots into a rescue shell. The administrator notes that /boot contains three vmlinuz images but the GRUB menu only lists the newest one. The administrator needs the server to boot the previously working kernel by default until the new kernel issue is resolved. Which file should the administrator edit to change the default kernel entry selected by GRUB 2 on this system?

Accepted Answer

/etc/default/grub. GRUB 2 separates user-editable defaults from generated configuration. Persistent settings like the default boot entry live in /etc/default/grub, and update-grub compiles them into /boot/grub/grub.cfg. Editing the generated file would be lost on the next kernel installation, so the administrator should set GRUB_DEFAULT in /etc/default/grub and regenerate. This preserves the change across kernel updates while allowing the older kernel to boot by default.

Answer

/etc/grub.d/40_custom

Answer

/boot/grub/grub.cfg

Answer

/etc/lilo.conf

Question 7

A Linux server uses systemd and has a custom service unit that must start after the network is fully online and after a remote filesystem is mounted. Which directive in the unit file ensures the service starts only after those dependencies are met?

Accepted Answer

After=network-online.target remote-fs.target. In systemd, ordering dependencies are expressed with After= and Before=, while requirement dependencies use Requires= and Wants=. To ensure a service starts only after the network is online and remote filesystems are mounted, the After= directive must list network-online.target and remote-fs.target. This guarantees the correct startup sequence without imposing a hard requirement that could cause the service to fail if the targets are not reached.

Answer

Before=network-online.target remote-fs.target

Answer

Requires=network-online.target remote-fs.target

Answer

Wants=network-online.target remote-fs.target

Question 8

A Linux router uses nftables for packet filtering and NAT. The administrator adds a rule to the postrouting chain of the nat table to masquerade traffic from the internal LAN (192.168.1.0/24) going out through eth0. After applying the ruleset with nft -f ruleset.nft, internal clients still cannot reach external web servers. The administrator confirms that IP forwarding is enabled. Which additional step is required for the masquerading to function?

Accepted Answer

Ensure the forward chain in the filter table accepts the traffic from 192.168.1.0/24 to the external interface.. The nat table's postrouting chain performs address translation but does not authorize packet forwarding. nftables evaluates the forward chain in the filter table for routed traffic, and if that chain's policy is drop or lacks an accept rule, the packets are discarded before translation matters. Adding an accept rule for the internal subnet in the forward chain resolves the issue.

Answer

Add a rule to the input chain of the filter table to accept traffic from 192.168.1.0/24.

Answer

Disable reverse path filtering by setting net.ipv4.conf.all.rp_filter to 0.

Answer

Change the masquerade rule to use the 'snat to' statement with the router's external IP address.

Question 9

A system administrator manages a CentOS 7 server with a single XFS filesystem on /dev/vg_data/lv_app mounted at /srv/app. The filesystem is nearly full and the volume group vg_data has 40 GB of free space available. The administrator needs to make the filesystem 20 GB larger without unmounting it and without losing existing data. Which sequence of commands should the administrator run?

Accepted Answer

lvextend -L +20G /dev/vg_data/lv_app && xfs_growfs /srv/app. XFS filesystems are grown online with xfs_growfs after the underlying logical volume has been enlarged. lvextend adds the requested extents to the LV, then xfs_growfs expands the filesystem to use the new space while it remains mounted. No unmount, mkfs, or data migration is needed.

Answer

lvextend -L +20G /dev/vg_data/lv_app && resize2fs /dev/vg_data/lv_app

Answer

xfs_growfs -L +20G /srv/app && lvextend /dev/vg_data/lv_app

Answer

lvresize -L +20G /dev/vg_data/lv_app && xfs_repair /srv/app

Question 10

A storage administrator has an existing software RAID5 array /dev/md0 built from three 2 TB SATA disks on a Linux server. The array is healthy but has no spare device. The administrator adds a fourth 2 TB disk, /dev/sdd, and wants to add it to the array so that it becomes an active member, increasing usable capacity while preserving existing data. Which command should the administrator run first?

Accepted Answer

mdadm --add /dev/md0 /dev/sdd. To expand a RAID5 array with an additional disk, the new device must first be added as a spare using mdadm --add. After the spare is synchronized, mdadm --grow with --raid-devices set to the new count reshapes the array and activates the spare, increasing usable capacity without recreating the array.

Answer

mdadm --grow /dev/md0 --raid-devices=4 --add /dev/sdd

Answer

mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd

Answer

mdadm --assemble /dev/md0 /dev/sda /dev/sdb /dev/sdc /dev/sdd

Question 11

A Debian 12 server boots with a monolithic kernel that has no initramfs support for the root disk. The administrator needs to pass the parameter 'root=/dev/sdb2' to the kernel at boot time without editing GRUB configuration files permanently. Which GRUB 2 command allows a one-time kernel parameter change at the boot menu?

Accepted Answer

Press 'e' to edit the selected menu entry, append 'root=/dev/sdb2' to the linux line, then press Ctrl+X or F10 to boot.. The correct approach is to edit the GRUB 2 menu entry at boot time by pressing 'e', modifying the linux line to include root=/dev/sdb2, and booting with Ctrl+X or F10. This applies the parameter only for that boot, leaving the system configuration unchanged. The other methods either enter a manual command shell, use the wrong key, or attempt permanent configuration changes.

Answer

Press 'Tab' to edit the kernel command line, add 'root=/dev/sdb2', and press Enter to boot.

Answer

Press 'c' to enter the GRUB command line, then run 'linux /vmlinuz root=/dev/sdb2' followed by 'boot'.

Answer

Run 'grub-mkconfig -o /boot/grub/grub.cfg' with the new root parameter, then reboot.

Question 12

An administrator is diagnosing slow boot on a systemd host. The output of systemd-analyze blame shows a custom storage unit taking 42 seconds. The administrator suspects the unit is waiting on a device that appears late. Which command should the administrator use to inspect the unit's dependencies and the ordering relationships that could explain the delay?

Accepted Answer

systemd-analyze critical-chain custom-storage.service. The critical-chain subcommand of systemd-analyze is designed to trace the timing path leading to a unit, combining ordering and dependency data with actual elapsed times. It reveals which preceding units or devices delay the target, making it the most direct tool for explaining a 42-second wait. Listing dependencies or dumping properties shows relationships without timing, and journal logs may be silent during a passive wait.

Answer

systemctl list-dependencies --all custom-storage.service

Answer

systemctl show custom-storage.service

Answer

journalctl -b -u custom-storage.service

Question 13

A technician needs to inspect the kernel command line that the currently running kernel received at boot on a systemd-based distribution, without rebooting. Which file should be read?

Accepted Answer

/proc/cmdline. The running kernel's exact command line is exposed through /proc/cmdline, which the kernel populates from the boot_params structure at early boot. This includes interactive GRUB edits and bootloader-injected options. Configuration files such as /etc/default/grub and grub.cfg only describe future or intended boots, and no standard /sys/kernel/boot_params exists. For live verification of kernel parameters, /proc/cmdline is the correct source.

Answer

/boot/grub/grub.cfg

Answer

/etc/default/grub

Answer

/sys/kernel/boot_params

Question 14

A Linux server uses a bonded interface bond0 in 802.3ad (LACP) mode with two slaves, eth0 and eth1. The switch ports are correctly configured for LACP. After a reboot, the administrator finds that bond0 is up, but only eth0 carries traffic; eth1 remains in a 'backup' state. Which command should the administrator run first to verify the bonding mode and active aggregator selection?

Accepted Answer

cat /proc/net/bonding/bond0. The bonding proc file is the authoritative source for mode, active aggregator, and per-slave state on Linux. Reading it first confirms whether the bond is truly in 802.3ad mode and whether eth1 is unselected because of LACP negotiation failure, missing switch configuration, or carrier issues before moving to NIC-level counters.

Answer

brctl show bond0

Answer

ip -s link show bond0

Answer

ethtool -S eth1

Question 15

An administrator is hardening a server that uses an initramfs generated by dracut. The requirement is to prevent the initramfs from automatically loading a specific storage driver and to ensure the real root filesystem's modules are included. Which TWO actions achieve these goals? (Choose two.)

Accepted Answer

Add the driver name to /etc/dracut.conf.d/blacklist.conf using the omit_drivers directive and regenerate the initramfs.. dracut reads configuration from /etc/dracut.conf.d/, where omit_drivers excludes modules from the initramfs and force_drivers guarantees inclusion. Together they let an administrator block a specific storage driver while ensuring the real root filesystem's modules are present. Regenerating with dracut -f applies the changes. The other options either add drivers, rely on hostonly heuristics, or include everything, none of which meet the precise hardening requirement.

Answer

Run dracut --regenerate-all --force with the --no-hostonly flag to include all available drivers.

Answer

Set hostonly=yes in /etc/dracut.conf and rebuild so that only modules for the current root device are included.

Answer

Use the instmods command inside a dracut module script to force-include the storage driver.