XK0-006 System Management Practice Test 6 — 15 Questions

Question 1

A Linux administrator needs to configure a system to automatically mount a USB drive at /mnt/usb whenever it is plugged in. The drive is formatted with ext4 and has the label 'BACKUP'. Which approach will achieve this with minimal manual intervention?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Add an entry to /etc/fstab using the label and options 'defaults,nofail,x-systemd.device-timeout=10' and enable systemd automount.. To automatically mount a USB drive when plugged in, the best approach is to use /etc/fstab with the filesystem label and systemd automount options. The label avoids device name changes, and options like nofail and x-systemd.automount enable automatic mounting when the device is detected. This integrates with systemd's mount handling.

Answer

Add an entry to /etc/fstab with the device path /dev/sdb1 and options 'defaults,noauto'.

Answer

Configure an autofs map that mounts the device by label when the mount point is accessed.

Answer

Create a udev rule that runs mount /dev/sdb1 /mnt/usb when the device is added.

Question 2

A Linux administrator needs to change the hostname of a system temporarily without rebooting. Which command should be used?

Accepted Answer

hostnamectl set-hostname newname. The 'hostnamectl set-hostname' command is the correct tool to change the system hostname on modern Linux distributions using systemd. It updates the hostname immediately and writes the change to /etc/hostname, ensuring persistence. This satisfies the requirement to change the hostname without rebooting while also making it permanent.

Answer

hostname newname

Answer

sysctl kernel.hostname=newname

Answer

nmcli general hostname newname

Question 3

A Linux administrator is troubleshooting a systemd service that fails to start during boot. The service unit file has a dependency on network.target, but the service still starts before the network is fully online. Which directive should be added to the unit file to ensure the service starts only after the network is fully configured?

Accepted Answer

After=network-online.target. To ensure a service starts after the network is fully online, you must use 'After=network-online.target' in conjunction with 'Wants=network-online.target'. The 'After' directive sets the ordering, ensuring the service starts only after network-online.target is reached. This target is only reached when the network is configured, unlike network.target which is reached earlier.

Answer

Wants=network-online.target

Answer

Requires=network.target

Answer

Before=network.target

Question 4

A Linux administrator notices that a critical application service managed by systemd keeps restarting every few seconds. The administrator wants to inspect the service's recent log entries and confirm which unit file path systemd is actually loading. Which TWO commands will provide this information? (Choose two.)

Accepted Answer

journalctl -u app.service -n 50. To diagnose a service restart loop, the administrator needs unit-scoped logs and the authoritative unit file path. Filtering the journal by unit with a count limit surfaces the recent failure messages, while querying the FragmentPath property reveals exactly which unit file systemd loaded, resolving conflicts between vendor and administrator copies. Together these commands isolate the cause and confirm the active configuration.

Answer

journalctl -f -p err

Answer

systemctl cat app.service

Answer

systemctl status app.service --no-pager

Question 5

A junior administrator needs to schedule a one-time job that runs the script /opt/backup.sh at 23:30 tonight on a server that uses systemd. The administrator wants the job to survive a reboot if the server restarts before the scheduled time. Which command correctly schedules this job?

Accepted Answer

systemd-run --on-calendar='23:30' /opt/backup.sh. On systemd-based systems, transient timers created with systemd-run offer a native way to schedule one-time execution at a calendar time while remaining tracked by the init system. The --on-calendar option defines the schedule, and the command after it is executed when the timer fires. This satisfies both the one-time and reboot-survival requirements better than at or cron.

Answer

echo /opt/backup.sh | at 23:30

Answer

at 23:30 -f /opt/backup.sh

Answer

crontab -e and add: 30 23 * * * /opt/backup.sh

Question 6

A Linux administrator needs to schedule a one-time job that runs a backup script at 2:30 AM next Wednesday. The job must not recur. Which command should the administrator use to schedule this task?

Accepted Answer

at 2:30 AM next Wednesday -f /usr/local/bin/backup.sh. The at command is specifically designed for one-time future execution. Specifying a time like '2:30 AM next Wednesday' schedules the job to run once and then removes it from the at queue. Cron and systemd timers are for recurring tasks, and batch runs based on load, not clock time.

Answer

crontab -e and add the line: 30 2 * * 3 /usr/local/bin/backup.sh

Answer

echo '/usr/local/bin/backup.sh' | batch -t 02:30

Answer

systemd-run --on-calendar='Wed 02:30' /usr/local/bin/backup.sh

Question 7

An administrator must extend an existing LVM volume group named vgdata by adding a new physical disk /dev/sdc so that the logical volume lvdata can grow. The disk has no partition table and will be used whole. Which sequence of commands correctly adds the disk and extends the logical volume?

Accepted Answer

pvcreate /dev/sdc; vgextend vgdata /dev/sdc; lvextend -l +100%FREE /dev/vgdata/lvdata; resize2fs /dev/vgdata/lvdata. Growing an LVM logical volume backed by an ext filesystem requires initializing the new disk as a physical volume, extending the existing volume group with it, extending the logical volume to use the free extents, and then resizing the filesystem with resize2fs. Using vgcreate instead of vgextend, or applying xfs_growfs without confirming XFS, breaks the sequence.

Answer

vgcreate vgdata /dev/sdc; lvextend -L +2T /dev/vgdata/lvdata; xfs_growfs /data

Answer

pvcreate /dev/sdc; vgextend vgdata /dev/sdc; lvresize -l +100%FREE /dev/vgdata/lvdata; xfs_growfs /dev/vgdata/lvdata

Answer

pvcreate /dev/sdc; vgcreate vgdata /dev/sdc; lvextend -l +100%FREE /dev/vgdata/lvdata; resize2fs /dev/vgdata/lvdata

Question 8

A Linux administrator is troubleshooting a system where the /home directory is running out of space. The administrator needs to identify which files are consuming the most space within /home, sorted from largest to smallest. Which command should the administrator use?

Accepted Answer

find /home -type f -exec du -h {} + | sort -rh. To find the largest files recursively, find with -type f and -exec du -h produces a list of all files with human-readable sizes, and sort -rh orders them largest first. The other commands either summarize directories, show filesystem totals, or only list top-level contents without recursion.

Answer

du -sh /home/* | sort -h

Answer

df -h /home | sort -k5 -rn

Answer

ls -lS /home | head -n 10

Question 9

A Linux server hosts a web application that must start only after the network is fully online and the database service is accepting connections. The administrator is writing a custom systemd unit for the application. Which directive combination correctly enforces these ordering and dependency requirements?

Accepted Answer

Requires=network-online.target db.service and After=network-online.target db.service. Correct systemd dependency design separates ordering from requirement strength. After establishes start ordering, while Requires creates a hard dependency that pulls in the listed units and stops the dependent service if they fail. Combining Requires with After for both network-online.target and db.service ensures the application starts only after the network is online and the database has been activated.

Answer

After=network-online.target db.service and Wants=network-online.target db.service

Answer

BindsTo=network-online.target db.service and Before=network-online.target db.service

Answer

Wants=network-online.target db.service and Before=db.service

Question 10

A Linux administrator is configuring a new server and needs to ensure that the firewall allows incoming SSH connections on port 22 and HTTP connections on port 80, while blocking all other incoming traffic. The system uses firewalld. Which TWO commands should the administrator use to achieve this? (Choose two.)

Accepted Answer

firewall-cmd --permanent --add-service=http. To permanently allow SSH and HTTP, the administrator must add each service to the permanent configuration using firewall-cmd --permanent --add-service=ssh and --add-service=http. After that, a reload is needed to apply the changes. The other options either combine ports instead of services, apply only runtime changes, or are for applying changes rather than defining them.

Answer

firewall-cmd --permanent --add-port=22/tcp --add-port=80/tcp

Answer

firewall-cmd --reload

Answer

firewall-cmd --zone=public --add-service=ssh --add-service=http

Question 11

A Linux administrator needs to create a new logical volume named 'data' in the volume group 'vg01' with a size of 50GB, and format it with the XFS filesystem. Which sequence of commands should the administrator use?

Accepted Answer

lvcreate -L 50G -n data vg01; mkfs.xfs /dev/vg01/data. The correct sequence is to use lvcreate with -L to specify size in gigabytes and -n for the name, then mkfs.xfs to format the new logical volume. The device path /dev/vg01/data is standard. Other options misuse options, use the wrong command, or add unnecessary steps.

Answer

lvcreate -L 50G -n data vg01; mkfs -t xfs /dev/vg01/data; mount /dev/vg01/data /mnt

Answer

lvcreate -l 50G -n data vg01; mkfs.xfs /dev/mapper/vg01-data

Answer

vgcreate -L 50G -n data vg01; mkfs.xfs /dev/vg01/data

Question 12

A Linux administrator wants to limit the total amount of memory available to all processes in a user slice to 2GB. Which command should be used to apply this limit persistently?

Accepted Answer

systemctl set-property user.slice MemoryMax=2G. The 'systemctl set-property' command is the correct tool to apply resource control settings to a systemd unit or slice. Setting MemoryMax=2G on user.slice enforces a hard memory limit for all processes in that slice. This change is persistent by default, stored in a drop-in directory, and takes effect immediately.

Answer

echo 'user.slice MemoryMax=2G' > /etc/systemd/system/user.slice.d/limits.conf

Answer

systemctl edit --full user.slice

Answer

systemctl set-property user.slice MemoryLimit=2G

Question 13

A Linux administrator needs to locate all files in the /var directory that have been modified within the last 30 minutes and are larger than 10MB. Which command accomplishes this task?

Accepted Answer

find /var -mmin -30 -size +10M. The correct command is `find /var -mmin -30 -size +10M`. The `-mmin -30` option tells find to match files modified less than 30 minutes ago (the minus sign means 'less than'), and `-size +10M` matches files larger than 10 megabytes. This combination precisely meets the requirement of files modified within the last 30 minutes and larger than 10MB.

Answer

find /var -mmin 30 -size +10M

Answer

locate /var -mmin -30 -size +10M

Answer

find /var -mtime -30 -size +10M

Question 14

An administrator wants to grant a specific user, 'jdoe', read and write access to a file that is owned by root:root with permissions 640. The administrator does not want to change the file's owner or group. Which approach should be used?

Accepted Answer

Use setfacl -m u:jdoe:rw file. POSIX ACLs allow granting permissions to specific users or groups without altering the file's owner or group. The command 'setfacl -m u:jdoe:rw file' adds an ACL entry giving jdoe read and write access while leaving root:root ownership and the 640 mode intact. This is the standard, least-disruptive approach for per-user access on a shared file.

Answer

Change file owner to jdoe

Answer

Use chmod o+rw file

Answer

Add jdoe to the root group

Question 15

A user needs to view the first 15 lines of a large log file. Which command is most appropriate?

Accepted Answer

head -n 15 filename. The command 'head -n 15 filename' is the most appropriate and efficient way to view the first 15 lines of a file. The head command is designed for this purpose, and the -n option specifies the number of lines. This is a standard Linux command and is more direct than piping cat to head.

Answer

cat filename | head -n 15

Answer

less -N 15 filename

Answer

tail -n 15 filename