XK0-006 Practice Test 26 — 15 Questions

Question 1

An administrator is writing a Dockerfile. They need to set a default command that can be overridden when running the container. Which instruction should be used?

Accepted Answer

CMD. CMD provides defaults that can be overridden by command-line arguments, while ENTRYPOINT cannot be easily overridden without --entrypoint.

Answer

RUN

Answer

ENTRYPOINT

Answer

EXPOSE

Question 2

A DevOps team uses Podman to run containers rootlessly. Which TWO of the following characteristics apply to rootless Podman compared to Docker? (Select TWO).

Accepted Answer

It uses the same CLI syntax as Docker. Podman does not require a daemon (no central daemon), and it can run containers without root privileges by default using user namespaces.

Answer

It can only run containers as root

Answer

It requires a running daemon at all times

Answer

It relies on a central registry for all images

Question 3

An administrator is troubleshooting a service that fails to start with a 'Permission denied' error. The administrator runs `strace -f -o /tmp/strace.log systemctl start myservice`. Which of the following best describes what this command achieves?

Accepted Answer

It traces system calls for systemctl and its children, recording them to a file.. strace traces system calls; -f follows child processes; -o writes output to file.

Answer

It records the kernel messages related to the service start.

Answer

It monitors network connections opened by the service.

Answer

It traces library calls made by the service startup.

Question 4

A technician is troubleshooting a network connectivity issue. They need to trace the path packets take to a remote server and see the round-trip time for each hop. Which command should they use?

Accepted Answer

traceroute. traceroute (or tracepath) shows the path and RTT per hop.

Answer

ping

Answer

nslookup

Answer

nmap

Question 5

A Linux server is experiencing high CPU usage. Which TWO commands can be used to identify which processes are consuming the most CPU? (Choose two.)

Accepted Answer

ps aux --sort=-%cpu. top and ps are standard process monitoring tools that show CPU usage.

Answer

iostat

Answer

vmstat

Answer

free

Question 6

Which command displays the current routing table on a Linux system?

Accepted Answer

ip route. ip route shows the routing table. The older route command is deprecated.

Answer

ip neigh

Answer

ip addr

Answer

ip link

Question 7

A Linux administrator needs to view all current IPv4 addresses assigned to network interfaces on a system. Which command should be used?

Accepted Answer

ip addr. The 'ip addr' command displays all IP addresses assigned to network interfaces. 'ifconfig' is deprecated, 'ip link' shows link-layer info, and 'hostname -I' only shows primary IPs.

Answer

ip link show

Answer

ifconfig -a

Answer

hostname -I

Question 8

A system administrator is investigating high disk I/O on a server. Which command can provide disk utilization statistics, including average wait time (await) and percentage of CPU time during which I/O requests were issued (%util)?

Accepted Answer

iostat -x 1. The `iostat` command reports disk I/O statistics including await and %util.

Answer

free -h

Answer

sar -b 1 5

Answer

vmstat 1 5

Question 9

A technician wants to check the current IP address and subnet mask of the eth0 interface. Which command should they use?

Accepted Answer

ip addr show dev eth0. The `ip addr show dev eth0` (or `ip addr`) displays IP addresses and subnet masks.

Answer

nmcli dev show eth0

Answer

ip route show

Answer

ifconfig eth0

Question 10

A Linux system experiences intermittent network connectivity. The administrator suspects a faulty network cable or switch port. Which TWO of the following commands can provide information about link status, errors, and packet drops on the interface? (Choose TWO.)

Accepted Answer

ip link show eth0. ip link show displays link status and error counters; ethtool can show detailed link and error statistics.

Answer

ss -i

Answer

ip addr show eth0

Answer

tcpdump -i eth0

Question 11

An administrator needs to check the kernel ring buffer for hardware error messages from the current boot. Which command displays this information?

Accepted Answer

dmesg. dmesg displays the kernel ring buffer, which includes hardware-related messages from the current boot.

Answer

vmstat -f

Answer

journalctl -k -b 0

Answer

cat /var/log/boot.log

Question 12

A Linux administrator needs to view all listening TCP ports and the associated processes on a server. Which command should be used?

Accepted Answer

ss -tlnp. The ss command with -tlnp options shows listening TCP ports with process information, replacing netstat.

Answer

netstat -tulpn

Answer

lsof -i

Answer

nmap localhost

Question 13

A user reports that they cannot reach a website by name, but they can reach it by IP address. Which file should be checked first for possible misconfiguration?

Accepted Answer

/etc/resolv.conf. The /etc/resolv.conf file contains DNS resolver settings. If it is incorrect, name resolution will fail.

Answer

/etc/nsswitch.conf

Answer

/etc/hosts

Answer

/etc/sysconfig/network

Question 14

A Linux engineer is investigating high disk I/O on a server. Which command provides disk I/O statistics including %util, await, r/s, and w/s?

Accepted Answer

iostat -x 1. iostat reports CPU and disk I/O statistics, with columns like %util, await, r/s, and w/s.

Answer

sar -b

Answer

vmstat 1 5

Answer

free -h

Question 15

A system administrator is troubleshooting a bash script that fails when run from cron but works when run from the terminal. Which two factors could explain this behavior? (Select TWO.)

Accepted Answer

The script uses interactive commands. Interactive commands (e.g., `read`, `select`, or commands that require a TTY) fail when run from cron, as cron does not allocate a terminal. The script expects user input or terminal interaction, which is not available in the cron environment, causing it to hang or error out. Option E is correct because cron runs with a minimal PATH (often `/usr/bin:/bin`), so the script may fail to locate commands that are found in the user's interactive shell PATH (e.g., `/usr/local/bin`).

Answer

The script uses a different shell interpreter

Answer

The script uses absolute paths

Answer

The script runs with a different user ID