XK0-006 Practice Test 31 — 15 Questions

Question 1

A system administrator is troubleshooting a custom systemd service that fails to start. Which of the following commands should be used to diagnose the issue? (Choose two.)

Accepted Answer

systemctl status myservice. The `systemctl status myservice` command (B) is correct because it shows the current state of the service, including whether it is active, failed, or inactive, along with recent log entries and the exit code. The `journalctl -u myservice` command (E) is correct because it retrieves the full systemd journal logs specifically for that unit, which is essential for diagnosing why the service failed to start, such as missing dependencies or configuration errors.

Answer

systemctl daemon-reload

Answer

systemctl enable myservice

Answer

systemctl list-units

Question 2

Based on the exhibit, what is the most likely cause of the 'PV Status: not available'?

Accepted Answer

The physical volume is missing or disconnected.. The 'PV Status: not available' message in LVM indicates that the system cannot access the physical volume. This typically occurs when the underlying disk or partition is missing, disconnected, or has failed. Since LVM relies on the physical volume being present for volume group and logical volume operations, a missing or disconnected physical volume is the most direct cause.

Answer

The volume group is corrupted.

Answer

The logical volume is not mounted.

Answer

LVM metadata is damaged.

Question 3

A process is consuming excessive CPU. The administrator wants to reduce its priority. Which command should be used?

Accepted Answer

renice +10 PID. The `renice` command is used to change the priority of an already running process. By specifying `+10`, the administrator increases the nice value, which lowers the process's scheduling priority and reduces its CPU consumption. This directly addresses the requirement to reduce the priority of a currently executing process.

Answer

taskset -c 0 PID

Answer

nice -n -20 PID

Answer

chrt -r 99 PID

Question 4

A new user 'jdoe' has been added using the command 'useradd jdoe', but upon first login, the user receives a message that the home directory does not exist. Which command should the administrator run to resolve this issue while also populating the home directory with default skeleton files?

Accepted Answer

useradd -m jdoe. The `useradd -m jdoe` command creates the user's home directory and copies the default skeleton files from `/etc/skel` into it. Since the user was initially created without the `-m` flag, the home directory was not created, causing the login error. Running `useradd -m` on an existing user will create the missing home directory and populate it with skeleton files, resolving the issue.

Answer

chown jdoe:jdoe /home/jdoe

Answer

mkdir /home/jdoe; cp /etc/skel/* /home/jdoe/

Answer

usermod -d /home/jdoe jdoe

Question 5

Based on the exhibit, the myapp service fails to start. Which troubleshooting step should be taken first?

Accepted Answer

Check that the application's configuration file exists and is readable. The exhibit shows a systemd unit file for the myapp service with `ExecStart=/usr/local/bin/myapp` and `Restart=on-failure`. The service fails to start, and the most common cause for such a failure is a missing or misconfigured application configuration file that the binary expects at launch. Option D is correct because verifying the configuration file's existence and readability is a fundamental prerequisite before investigating deeper issues like permissions or logs.

Answer

Increase the RestartSec value to allow more time for startup

Answer

Verify that /usr/local/bin/myapp has execute permission

Answer

Inspect the system journal for more detailed error messages

Question 6

An organization is migrating from a legacy automation tool to Ansible. Which of the following best describes the role of Ansible playbooks in configuration management?

Accepted Answer

YAML files that declare the desired state of systems and tasks to achieve it.. Ansible playbooks are YAML files that declare the desired state of systems and the tasks to achieve that state, making them the core configuration management tool in Ansible. They are idempotent, meaning running them multiple times yields the same result, and they use modules to enforce configurations without requiring an agent on managed nodes.

Answer

Executable scripts written in Python that run on managed nodes.

Answer

Configuration files that list the inventory of managed hosts.

Answer

Shell scripts that execute ad-hoc commands across servers.

Question 7

Refer to the exhibit. A Docker container using a bind mount fails to start with a permission error. What is the most likely cause?

Accepted Answer

SELinux is blocking the mount.. When a Docker container uses a bind mount and fails with a permission error, SELinux is a common cause because it enforces mandatory access controls that can block container processes from accessing host files. By default, SELinux labels container processes with a confined domain (e.g., container_t), and if the bind-mounted host directory lacks the proper SELinux context (e.g., container_file_t), the mount is denied. This is resolved by adding the `:Z` or `:z` flag to the bind mount in the Docker run command to relabel the host directory appropriately.

Answer

The container is running in privileged mode.

Answer

The Docker daemon is not running as root.

Answer

The volume path on the host does not exist.

Question 8

A company requires that all systems be configured to log all authentication attempts, both successful and failed. Which configuration file and directive should be used to ensure all auth messages are logged to /var/log/secure?

Accepted Answer

In /etc/rsyslog.conf: authpriv.* /var/log/secure. In rsyslog, the `authpriv` facility covers authentication and authorization messages, including both successful and failed login attempts. The directive `authpriv.* /var/log/secure` directs all messages from this facility to `/var/log/secure`, which is the standard secure log file on RHEL/CentOS systems. This meets the requirement to log all authentication attempts.

Answer

In /etc/rsyslog.conf: *.info /var/log/secure

Answer

In /etc/rsyslog.conf: auth.* /var/log/secure

Answer

In /etc/rsyslog.conf: kern.* /var/log/secure

Question 9

A Linux administrator needs to check which process is using the most memory on a system. The administrator wants to view dynamically updating list of processes sorted by memory usage. Which command should the administrator use?

Accepted Answer

top -o %MEM. The `top` command provides a real-time, dynamically updating view of system processes. The `-o %MEM` option sorts the process list by memory usage (the %MEM column), allowing the administrator to immediately see which process is consuming the most memory. This directly meets the requirement for a dynamically updating list sorted by memory usage.

Answer

ps aux --sort=-%mem

Answer

htop -s MEM

Answer

vmstat 1 5

Question 10

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 11

A company needs to verify that the Apache HTTP server is running and see its current status along with recent log entries. Which command should be used?

Accepted Answer

systemctl status httpd. The `systemctl status httpd` command is correct because it provides a comprehensive view of the Apache HTTP server's current state (active/inactive), its process ID, memory usage, and the most recent log entries from the service's journal. This aligns with the question's requirement to both verify the service is running and see its status along with recent log entries, all in a single command output.

Answer

service httpd status

Answer

journalctl -u httpd

Answer

systemctl list-units --type=service

Question 12

Given the Dockerfile in the exhibit, which best practice is being violated?

Accepted Answer

Not combining apt-get update and install in one RUN command. The Dockerfile violates the best practice of combining `apt-get update` and `apt-get install` in a single RUN command. When these are separated, Docker caches the layer from `apt-get update`, so subsequent builds may use a stale package index, potentially installing outdated or vulnerable packages. Combining them ensures that the update and install happen atomically, reducing image size and guaranteeing a fresh package index.

Answer

Using a non-LTS base image

Answer

Not using a .dockerignore file

Answer

Running apt-get update without cache cleanup

Question 13

Refer to the exhibit. A network administrator is troubleshooting a failed network connection. Based on the journalctl output, what is the most likely cause?

Accepted Answer

The network interface eth0 is not physically connected.

Answer

The NetworkManager service is not running.

Answer

The network configuration file has an invalid IP address.

Answer

The DHCP server is unreachable.

Question 14

Refer to the exhibit. A server administrator wants to ensure that when a user logs out, all processes started by that user are terminated. Which line should be added to the configuration?

Accepted Answer

KillUserProcesses=yes. The setting 'KillUserProcesses=yes' will terminate user processes on logout. The default is 'no' as shown in the exhibit.

Answer

IdleAction=kill

Answer

HandleLidSwitch=ignore

Answer

NAutoVTs=0

Question 15

Which THREE of the following are commonly used configuration management and automation tools in the Linux ecosystem? (Choose THREE.)

Accepted Answer

Ansible. Ansible is a configuration management and automation tool that uses SSH for agentless communication and YAML-based playbooks to define desired system states. It is widely adopted in Linux environments for tasks such as software provisioning, configuration drift remediation, and orchestration, making it a correct choice for this question.

Answer

Terraform

Answer

Nagios