XK0-006 Practice Test 22 — 15 Questions

Question 1

A user wants to run a Docker container in detached mode, remove it automatically after it stops, and map host port 8080 to container port 80. Which command accomplishes this?

Accepted Answer

docker run -d --rm -p 8080:80 image. docker run --rm -d -p 8080:80 image runs in detached mode (-d), auto-removes (--rm), and maps port 8080 to 80.

Answer

docker run -it --rm -p 80:8080 image

Answer

docker create --rm -p 8080:80 image

Answer

docker start -d -p 8080:80 image

Question 2

A Linux administrator wants to ensure a bash script stops execution immediately if any command fails. Which line should be added to the script?

Accepted Answer

set -e. The 'set -e' command causes the script to exit immediately when a command returns a non-zero exit status.

Answer

set -x

Answer

set -u

Answer

set -o pipefail

Question 3

Which of the following is a key difference between Docker and Podman?

Accepted Answer

Podman can run containers without root privileges.. Podman is daemonless and can run containers rootless, while Docker typically runs with a daemon and root privileges.

Answer

Docker does not support container images.

Answer

Podman requires a daemon to run containers.

Answer

Docker can only run on Linux.

Question 4

An administrator notices that a process is running with the context 'unconfined_u:unconfined_r:unconfined_t:s0'. What does this indicate about SELinux?

Accepted Answer

The process is running in an unconfined domain.. The 'unconfined' domain means the process is not restricted by SELinux policy; it can run as if SELinux is disabled.

Answer

The process is running in permissive mode.

Answer

SELinux is disabled.

Answer

The process is confined by a targeted policy.

Question 5

To harden SSH, an administrator needs to disable root login over SSH. Which directive should be set in /etc/ssh/sshd_config?

Accepted Answer

PermitRootLogin no. PermitRootLogin no prevents root from logging in via SSH.

Answer

RootLogin no

Answer

DenyUsers root

Answer

AllowUsers root

Question 6

A Linux system is experiencing high CPU load. The administrator runs 'top' and sees that the 'kworker' processes are consuming significant CPU time. What is the most likely cause?

Accepted Answer

A hardware interrupt storm caused by a failing disk controller. The 'kworker' processes in the 'top' output indicate kernel workqueue threads that handle deferred work. High CPU usage by kworker is typically caused by a hardware interrupt storm, often from a failing disk controller or other faulty hardware generating excessive interrupts that the kernel must service. This forces the workqueue to constantly process interrupt-related tasks, consuming significant CPU time.

Answer

A kernel module memory leak

Answer

A user process stuck in an infinite loop

Answer

Insufficient memory causing swapping

Question 7

The administrator wants to block the IP address shown in the exhibit. Which command should be used?

Accepted Answer

iptables -A INPUT -s 192.168.1.100 -j DROP. `iptables -A INPUT -s 192.168.1.100 -j DROP` appends a rule to the INPUT chain that drops all incoming packets from the source IP 192.168.1.100. This is the standard Linux firewall command for blocking traffic at the network layer using netfilter, and it works immediately without requiring a service restart.

Answer

fail2ban

Answer

echo '192.168.1.100' >> /etc/hosts.deny

Answer

firewall-cmd --add-source=192.168.1.100 --permanent

Question 8

Which command displays the last successful login times for all users?

Accepted Answer

lastlog. lastlog displays the last login for each user.

Answer

who /var/log/wtmp

Answer

lastb

Answer

last

Question 9

After updating the kernel, the system fails to boot and displays 'Error 15: File not found' from GRUB. What is the most likely cause?

Accepted Answer

The kernel image is missing or the path in grub.cfg is incorrect. GRUB error 15 indicates that the specified file path in the GRUB configuration (grub.cfg) cannot be found. Since the error occurs after a kernel update, the most likely cause is that the new kernel image file is missing from the boot partition or the path in grub.cfg does not match the actual file location, preventing GRUB from loading the kernel.

Answer

The GRUB configuration file is missing

Answer

The initramfs image is missing

Answer

The hard drive has failed

Question 10

An administrator needs to allow incoming TCP traffic on port 8443 using firewalld. Which command should be used to make this change persistent?

Accepted Answer

firewall-cmd --add-port=8443/tcp --permanent && firewall-cmd --reload. To add a port, use firewall-cmd --add-port=8443/tcp --permanent and then reload.

Answer

firewall-cmd --zone=public --add-port=8443/tcp

Answer

firewall-cmd --add-service=8443/tcp --permanent

Answer

firewall-cmd --add-port=8443/tcp

Question 11

An administrator is configuring AppArmor for a custom application. Which THREE commands are used to manage AppArmor profiles?

Accepted Answer

aa-status. aa-status displays the status of AppArmor profiles. aa-complain sets a profile to complain mode (logs violations but does not enforce). aa-enforce sets a profile to enforce mode.

Answer

aa-logprof

Answer

apparmor_parser

Question 12

An administrator wants to monitor disk I/O performance in real-time, focusing on metrics like wait time and I/O queue size. Which tool is best suited for this?

Accepted Answer

iostat -x 1. iostat provides detailed disk I/O statistics including await, svctime, %util, and queue size.

Answer

vmstat

Answer

sar -b

Answer

free -h

Question 13

An administrator is configuring auditd to monitor changes to the /etc/passwd file. Which three commands are part of the auditd toolset for setting up and reviewing audit rules?

Accepted Answer

aureport. auditctl adds rules, ausearch searches logs, aureport generates reports. auditd is the daemon, not a command for rules. aulog is not a standard tool.

Answer

aulog

Answer

auditd

Question 14

Which THREE of the following commands are used to manage iptables rules? (Select THREE.)

Accepted Answer

iptables -I. iptables is used with options -A (append), -I (insert), -D (delete). -L lists rules, -F flushes. -j is for target, not a command itself. -p is for protocol. -s is source.

Answer

iptables -p

Answer

iptables -j

Question 15

Which command displays the current SELinux mode?

Accepted Answer

getenforce. getenforce displays whether SELinux is enforcing, permissive, or disabled.

Answer

setenforce

Answer

selinuxenabled

Answer

sestatus