XK0-006 Practice Test 3 — 25 Questions

Question 1

Refer to the exhibit. A user wants to execute the script 'script.sh' but receives a 'Permission denied' error. Which action should be taken to allow execution?

Accepted Answer

Add execute permission with chmod +x script.sh. The 'Permission denied' error indicates the script lacks the execute permission for the user. The `chmod +x script.sh` command adds the execute permission bit to the file's mode, allowing the user to run it as a program. This is the direct and correct fix for the issue.

Answer

Change the owner to the user with chown

Answer

Change the group to the user's primary group

Answer

Set the permissions to 644 with chmod

Question 2

A system is experiencing high CPU usage due to a background process with PID 2345. The administrator wants to reduce the process's priority by 5 without stopping it. Which command should be used?

Accepted Answer

renice -n +5 -p 2345. The correct command is `renice -n +5 -p 2345` because `renice` adjusts the scheduling priority of a running process. A positive niceness value (+5) lowers the priority (makes the process 'nicer' to others), which reduces CPU usage. The `-n` flag specifies the adjustment value, and `-p` identifies the process by PID. This matches the requirement to reduce priority by 5 without stopping the process.

Answer

kill -STOP 2345

Answer

renice -n -5 -p 2345

Answer

kill -9 2345

Question 3

Refer to the exhibit. A Linux administrator created a systemd service file for a custom script. When starting the service, it fails with 'Unit myservice.service entered failed state.' Which of the following is the most likely cause?

Accepted Answer

The ExecStart path is relative. The most likely cause is that the ExecStart path is relative. Systemd requires absolute paths for ExecStart directives; a relative path (e.g., `./script.sh` or just `script.sh`) will cause the unit to fail immediately because systemd cannot resolve the executable location. The error 'entered failed state' typically results from this path resolution failure.

Answer

The service type should be forking

Answer

The service file lacks an [Install] section

Answer

The Requires directive is missing

Question 4

An administrator runs the command `ls -l file.txt` and sees the permissions `-rwsr-xr-x`. What special permission is set on this file?

Accepted Answer

SUID. The 's' in the owner execute position indicates the SUID (Set User ID) permission is set.

Answer

SGID

Answer

Sticky bit

Answer

No special permission

Question 5

A technician needs to check which package provides the file /usr/bin/foo on a CentOS 8 system. Which command should be used?

Accepted Answer

rpm -qf /usr/bin/foo. On RPM-based systems, rpm -qf queries the package that owns a given file.

Answer

rpm -V /usr/bin/foo

Answer

rpm -qi /usr/bin/foo

Answer

rpm -ql /usr/bin/foo

Question 6

A system administrator runs the command 'chmod 4755 /usr/local/bin/backup'. What effect does this have on the file?

Accepted Answer

Sets the SUID bit and gives rwxr-xr-x permissions. The 4 in the first digit sets the SUID bit, so the file runs with the owner's permissions. 755 sets rwxr-xr-x.

Answer

Sets the sticky bit and gives rwxr-xr-x permissions

Answer

Sets the SGID bit and gives rwxr-xr-x permissions

Answer

Sets the SUID bit and gives rwxrwxr-x permissions

Question 7

A Linux server is experiencing intermittent connectivity issues. The administrator reviews the system logs and finds the following messages: 'NETDEV WATCHDOG: eth0: transmit queue 0 timed out'. Which THREE actions are likely to resolve this issue? (Choose three.)

Accepted Answer

Disable NIC offloading features using 'ethtool -K eth0 tx off sg off'.. The 'NETDEV WATCHDOG: eth0: transmit queue 0 timed out' error often indicates that the NIC's hardware offloading features (such as TCP segmentation offload, scatter-gather) are causing the driver to hang or fail to complete transmissions. Disabling these offloads with 'ethtool -K eth0 tx off sg off' forces the CPU to handle packet segmentation and reduces the load on the NIC, which can resolve the timeout.

Answer

Increase the transmit queue length using 'ifconfig eth0 txqueuelen 10000'.

Answer

Change the MTU on the interface to 9000.

Question 8

A server with multiple disks is configured with RAID 5 for performance and redundancy. The administrator notices that write performance is lower than expected. Which RAID level would provide better write performance while still offering fault tolerance with the same number of disks (minimum 4)?

Accepted Answer

RAID 10. RAID 10 (striping of mirrors) provides better write performance than RAID 5 because it does not incur the overhead of calculating and writing parity data on every write operation. With a minimum of four disks, RAID 10 offers fault tolerance (each mirror can survive one disk failure) while delivering the full write speed of the underlying disks, unlike RAID 5 which must update parity across all disks.

Answer

RAID 0

Answer

RAID 6

Answer

RAID 1

Question 9

A user reports that their system is unable to boot after a recent kernel update. The system displays a 'kernel panic' message. Which of the following is the MOST efficient way to boot into a previous kernel version?

Accepted Answer

Select an older kernel from the GRUB menu. The GRUB bootloader stores multiple kernel versions after an update, allowing you to select a previous kernel from its menu at boot time. Choosing an older kernel bypasses the faulty new kernel without requiring additional tools or recovery media, making it the most efficient method to resolve a kernel panic caused by a recent update.

Answer

Use the systemd rescue mode

Answer

Reinstall the operating system

Answer

Boot from a live CD and chroot

Question 10

A cloud engineer needs to automate the deployment of a new virtual machine with a specific configuration using Ansible. Which file format is typically used for Ansible playbooks?

Accepted Answer

YAML. Ansible playbooks are written in YAML (YAML Ain't Markup Language) because it is human-readable, supports complex data structures like lists and dictionaries, and is designed for configuration management. YAML's indentation-based syntax aligns with Ansible's declarative approach, allowing tasks, variables, and handlers to be defined cleanly without the overhead of brackets or tags.

Answer

JSON

Answer

XML

Answer

INI

Question 11

Which TWO statements are true regarding the use of Ansible for automation? (Choose TWO.)

Accepted Answer

Ansible playbooks are written in YAML.. Option B is correct because Ansible playbooks are defined in YAML, a human-readable data serialization format that describes tasks, plays, and roles executed by the Ansible engine. Option C is correct because Ansible is agentless: it does not require any software installed on managed nodes and communicates over standard SSH (or WinRM for Windows hosts) to push modules and execute tasks. Option A is incorrect because Ansible can run from any control machine, including a laptop or a CI runner, and does not mandate a dedicated master server. Option D is incorrect because Ansible uses a push-based model, where the control node pushes playbooks/modules to targets, not a pull model like Puppet or Chef agents. Option E is incorrect because Ansible modules are written in Python (or any language returning JSON), not Ruby.

Answer

Ansible requires a dedicated master server to manage nodes.

Answer

Ansible uses a pull-based model where nodes fetch configurations from a central server.

Answer

Ansible modules are written in Ruby.

Question 12

A security audit reveals that an SELinux boolean 'httpd_can_network_connect' is currently off, but a web application requires Apache to connect to a database server. Which command should the administrator use to enable this boolean persistently?

Accepted Answer

setsebool -P httpd_can_network_connect on. The command 'setsebool -P httpd_can_network_connect on' is correct because setsebool modifies SELinux booleans at runtime, and the -P flag makes the change persistent across reboots by writing it to the policy store. This enables Apache to initiate network connections to the database server as required.

Answer

setenforce 1

Answer

setsebool httpd_can_network_connect 1

Answer

getsebool httpd_can_network_connect

Question 13

A server running RHEL 8 fails to boot with a 'Dependency failed for /data' error. The /data filesystem is an ext4 partition on /dev/sdb1. Which sequence of steps should be taken to repair the filesystem?

Accepted Answer

Boot into rescue mode, run 'umount /dev/sdb1', then 'fsck.ext4 -f /dev/sdb1'. To repair an ext4 filesystem that failed to mount at boot, you must boot into rescue mode (or single-user), ensure the filesystem is unmounted, then run 'fsck.ext4 -f /dev/sdb1' to force a check and repair. fsck must never run on a mounted read-write filesystem, and rescue mode gives you a clean environment where /data is not mounted. This is the standard RHEL recovery procedure.

Answer

Use 'xfs_repair /dev/sdb1' since it's ext4

Answer

Run 'fsck.ext4 -f /dev/sdb1' from the running system

Answer

Remount the filesystem as read-only and run fsck

Question 14

A technician wants to check the disk I/O statistics, focusing on the average I/O wait time and utilization percentage. Which command provides this information?

Accepted Answer

iostat -x. The iostat -x command displays extended disk I/O statistics, including per-device metrics such as average wait time (await), utilization percentage (%util), and queue sizes. The -x flag is specifically what surfaces these extended columns, making it the correct tool for analyzing I/O wait and utilization. sar -b reports overall block device activity but not per-device extended metrics like await and %util.

Answer

sar -b

Answer

vmstat -d

Answer

free -h

Question 15

An administrator runs 'systemctl list-units' and sees that httpd.service is in a failed state. To quickly see the error message that caused the failure, which command should be used?

Accepted Answer

systemctl status httpd.service. The `systemctl status httpd.service` command displays the current state of the service, including the most recent log entries from the journal that show the error messages causing the failure. This is the quickest way to see the failure reason without filtering or additional options, as it directly outputs the relevant error lines from the service's unit.

Answer

systemctl show httpd.service -p ExecMainStatus

Answer

journalctl -p err -u httpd.service

Answer

systemd-analyze blame

Question 16

A systems administrator writes a Bash script named 'backup.sh' and wants it to run with the Bash shell. Which line should appear first in the script?

Accepted Answer

#!/bin/bash. The shebang line `#!/bin/bash` is required as the first line to instruct the operating system to execute the script using the Bash shell interpreter located at `/bin/bash`. Without this line, the script may be run by a different shell (e.g., `/bin/sh`), leading to syntax or behavior differences. The shebang must start with `#!` followed by the absolute path to the interpreter.

Answer

# This is a bash script

Answer

#/bin/bash

Answer

#!/bin/sh

Question 17

A technician has just performed system maintenance and wants to verify that the server has been running continuously for the past 30 days. Which command should the technician use?

Accepted Answer

uptime. The `uptime` command displays how long the system has been running since the last boot, including the current time, number of logged-in users, and load averages. By checking the output, the technician can verify if the server has been running continuously for the past 30 days (e.g., 'up 30 days'). This directly answers the question without querying logs or processes.

Answer

systemctl status rsyslog

Answer

ps aux

Answer

date

Question 18

A Linux administrator is tasked with adding a new 1TB hard drive to a server. The drive has been partitioned and formatted with ext4, resulting in the device /dev/sdb1. The administrator needs the drive to be mounted persistently at /data. After adding an entry to /etc/fstab, the administrator runs 'mount -a' and sees the error: 'mount: /data: mount point does not exist.' Which of the following should the administrator do first to resolve the issue?

Accepted Answer

Create the /data directory with mkdir. The error 'mount point does not exist' indicates that the directory /data has not been created on the filesystem. The mount command requires an existing directory to attach the device to. Creating the /data directory with mkdir resolves this, allowing mount -a to succeed.

Answer

Run mkfs.ext4 on /dev/sdb1

Answer

Reboot the server

Answer

Run fsck on /dev/sdb1

Question 19

After a system update, a custom application no longer runs due to a shared library error. The library exists on the system but is in a non-standard path. Which environment variable should be checked or set to resolve this?

Accepted Answer

LD_LIBRARY_PATH. The LD_LIBRARY_PATH environment variable tells the dynamic linker (ld.so) where to search for shared libraries before the standard system paths. When a custom application fails with a shared library error after an update, and the library exists in a non-standard path, setting LD_LIBRARY_PATH to include that path resolves the issue by allowing the linker to find the library at runtime.

Answer

LD_PRELOAD

Answer

PATH

Answer

LD_RUN_PATH

Question 20

A Linux administrator notices that the system’s disk I/O performance has degraded significantly. Running 'iostat -x 1' shows high %util values on /dev/sda, but low await. Which of the following is the most likely issue?

Accepted Answer

There are many concurrent I/O requests (high queue depth).. High %util with low await indicates that the device is busy processing many concurrent I/O requests, but each request completes quickly. This is characteristic of a high queue depth where the disk is saturated with parallel requests, not that individual requests are slow. The low await confirms that the disk itself is responding fast, so the bottleneck is the volume of simultaneous I/O, not latency per request.

Answer

The filesystem is nearly full.

Answer

The disk cable is loose or faulty.

Answer

The disk is failing and needs replacement.