XK0-006 Practice Test 19 — 15 Questions

Question 1

Which command would a Linux administrator use to locate all files in the /var/log directory that have been modified within the last 7 days?

Accepted Answer

find /var/log -mtime -7. The find command with -mtime -7 finds files modified less than 7 days ago. The other options are either incorrect or not suitable for this task.

Answer

ls -lt /var/log | head -n 7

Answer

grep -mtime -7 /var/log

Answer

locate -mtime -7 /var/log

Question 2

Which Kubernetes resource is used to store non-sensitive configuration data as key-value pairs that can be consumed by pods?

Accepted Answer

ConfigMap. ConfigMaps are used for non-sensitive configuration data. Secrets are for sensitive data like passwords. Deployments manage replicas of pods. Namespaces isolate resources.

Answer

Deployment

Answer

Secret

Answer

Namespace

Question 3

A developer wants to run a containerized application using Podman in a rootless environment. Which of the following is a key difference between Podman and Docker that the developer should be aware of?

Accepted Answer

Podman can run containers without a daemon. Podman supports rootless containers natively without requiring a daemon, unlike Docker which traditionally requires a daemon (dockerd) running as root.

Answer

Podman requires a daemon to manage containers

Answer

Podman only supports rootful containers

Answer

Podman uses a different CLI syntax than Docker

Question 4

A bash script uses a for loop to iterate over files in a directory. Which of the following correctly assigns each filename to the variable FILE?

Accepted Answer

for FILE in *.txt; do. The shell expands the wildcard pattern `*.txt` into a list of matching filenames before the `for` loop executes, and each filename is assigned to the variable `FILE` in turn. This approach is safe and efficient because it avoids parsing the output of `ls`, which can break with filenames containing spaces or special characters.

Answer

for FILE in $(ls *.txt); do

Answer

for FILE in 'ls *.txt'; do

Answer

for FILE = *.txt; do

Question 5

A user is unable to create new files in a directory. Which command can the administrator use to view the Access Control Lists (ACLs) associated with that directory?

Accepted Answer

getfacl. The `getfacl` command displays the Access Control Lists (ACLs) for a file or directory, showing both the standard POSIX permissions and any additional ACL entries (e.g., specific users or groups). Since the user cannot create new files, ACLs may be restricting write access beyond the basic mode bits, making `getfacl` the correct tool to inspect these extended permissions.

Answer

ls -l

Answer

setfacl

Answer

chmod

Question 6

A system administrator needs to ensure that the Apache HTTP server starts automatically at boot and is started immediately without rebooting. Which command accomplishes both tasks?

Accepted Answer

systemctl enable --now httpd. The `systemctl enable --now httpd` command combines two actions: it creates the necessary symlinks to start the Apache HTTP server automatically at boot (enable) and immediately starts the service without rebooting (start). The `--now` flag is the key to performing both tasks in a single command, fulfilling the requirement exactly.

Answer

systemctl disable --now httpd

Answer

systemctl enable httpd

Answer

systemctl start httpd

Question 7

A Linux administrator receives reports that a web application hosted on the company's internal server is intermittently slow. The server runs CentOS 7 and hosts multiple virtual hosts. The administrator checks system resources and notices that the system's swap usage is high. Which of the following is the MOST likely cause of the performance issue?

Accepted Answer

Insufficient physical memory for the workload. High swap usage indicates that the system is actively paging memory to disk because the available physical RAM is insufficient to hold the active working set. This causes significant latency because disk I/O is orders of magnitude slower than RAM, leading to intermittent slowdowns for the web application. The fact that multiple virtual hosts are running on CentOS 7 increases the memory demand, making insufficient physical memory the most likely root cause.

Answer

Misconfigured virtual host causing memory leaks

Answer

Network congestion on the internal network

Answer

Excessive CPU load from a runaway process

Question 8

An administrator needs to ensure that the SSH service only allows key-based authentication and disables password authentication. Which configuration file and directive should be modified?

Accepted Answer

/etc/ssh/sshd_config; PasswordAuthentication no. The SSH server configuration file is /etc/ssh/sshd_config, and setting 'PasswordAuthentication no' disables password-based logins, forcing key-based authentication. This directive must be set on the server side (sshd_config), not the client side (ssh_config), to enforce the policy for all incoming SSH connections.

Answer

/etc/ssh/sshd_config; PasswordAuthentication yes

Answer

/etc/ssh/sshd_config; PubkeyAuthentication no

Answer

/etc/ssh/ssh_config; PasswordAuthentication no

Question 9

A developer is writing a Bash script that must be portable across different Linux distributions. The script needs to check if a package is installed. Which command should be used to achieve this portability?

Accepted Answer

command -v package. The `command -v package` command is the most portable way to check if a package is installed across different Linux distributions because it uses the POSIX-standard `command` shell built-in, which works in any Bourne-compatible shell (bash, sh, dash, etc.) regardless of the underlying package manager. It returns the path to the executable if the package's binary is in the PATH, or nothing if it is not installed, making it distribution-agnostic.

Answer

which package

Answer

dpkg -l package

Answer

rpm -q package

Question 10

A technician needs to create a new ext4 filesystem on /dev/sdb1 and mount it persistently at /mnt/data. Which set of commands accomplishes this?

Accepted Answer

mkfs -t ext4 /dev/sdb1; mount /dev/sdb1 /mnt/data; echo '/dev/sdb1 /mnt/data ext4 defaults 0 2' >> /etc/fstab. The correct sequence must (1) create the filesystem with mkfs, (2) mount it now so it is usable immediately, and (3) add an /etc/fstab entry so the mount persists across reboots. Option A does all three in the right order using mkfs -t ext4, mount, and an fstab line with dump=0 and fsck pass=2. The fsck pass value of 2 is appropriate for a non-root filesystem.

Answer

mkfs.ext4 /dev/sdb1; echo '/dev/sdb1 /mnt/data ext4 defaults 0 2' >> /etc/fstab

Answer

mkfs.ext4 /dev/sdb1; mount /dev/sdb1 /mnt/data

Answer

echo '/dev/sdb1 /mnt/data ext4 defaults 0 2' >> /etc/fstab; mount -a

Answer

fdisk /dev/sdb1; mount /dev/sdb1 /mnt/data; echo '/dev/sdb1 /mnt/data ext4 defaults 0 2' >> /etc/fstab

Question 11

A company runs a critical web application on a single server using Docker containers. The application consists of a web frontend container and a backend API container. Recently, the server ran out of disk space due to Docker logs and temporary images. The sysadmin is tasked with automating cleanup to prevent recurrence. The solution must not disrupt running containers. Which approach should be taken?

Accepted Answer

Configure log rotation for containers using `--log-opt max-size=10m` and `--log-opt max-file=3` in the Docker run command, and schedule `docker image prune -f` weekly.. It addresses both root causes: log growth and dangling images. Configuring `--log-opt max-size=10m` and `--log-opt max-file=3` limits container log file size and count without stopping containers, while `docker image prune -f` removes unused images safely. This combination prevents disk exhaustion without disrupting running containers, meeting all requirements.

Answer

Increase disk space by adding a new volume.

Answer

Create a script that stops all containers, removes unused images, and restarts containers.

Answer

Schedule a cron job to run `docker system prune -a -f` daily.

Question 12

A user reports that a Linux workstation fails to boot and displays 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which of the following is the most likely cause?

Accepted Answer

The root filesystem device is incorrectly specified in the kernel command line.. The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates that the kernel cannot locate the root filesystem device. The most likely cause is that the root filesystem device is incorrectly specified in the kernel command line (e.g., via a bootloader parameter like root=), preventing the kernel from finding the correct block device to mount as root.

Answer

A filesystem listed in /etc/fstab has errors.

Answer

A memory module is faulty.

Answer

The boot loader is missing or corrupted.

Question 13

An administrator notices that a service named 'httpd' is not running. They want to check its current status and, if inactive, start it. Which set of systemctl commands should be used?

Accepted Answer

systemctl status httpd; if inactive, systemctl start httpd. systemctl status httpd shows the status; if inactive, systemctl start httpd starts it. The other options have incorrect commands or syntax.

Answer

systemctl list-units httpd; if inactive, systemctl run httpd

Answer

systemctl show httpd; if inactive, systemctl launch httpd

Answer

systemctl is-active httpd; if inactive, systemctl enable httpd

Question 14

A system administrator configures PAM to enforce account lockout after 3 failed login attempts. Which PAM module should be used?

Accepted Answer

pam_faillock. pam_faillock is the correct PAM module for enforcing account lockout after a specified number of failed login attempts. It tracks failed authentication attempts per user and can lock the account when the threshold (e.g., 3 attempts) is reached, typically by writing to a tally file like /var/log/faillock.

Answer

pam_pwquality

Answer

pam_securetty

Answer

pam_unix

Question 15

A security audit reveals that users can change their password without meeting complexity requirements. Which PAM module should be configured to enforce password complexity?

Accepted Answer

pam_pwquality. pam_pwquality is the PAM module that enforces password complexity requirements such as minimum length, character classes, and dictionary checks on Linux. It replaced the older pam_cracklib module and is configured in /etc/security/pwquality.conf and referenced in /etc/pam.d/system-auth or /etc/pam.d/common-password. Configuring it ensures users cannot set weak passwords that violate policy.

Answer

pam_faillock

Answer

pam_unix

Answer

pam_tally2