XK0-006 Practice Test 44 — 15 Questions

Question 1

A container named web2 exited with status 0. Which of the following is the most likely reason?

Accepted Answer

The container was stopped manually with docker stop. Exit code 0 indicates a successful termination. When a container exits with status 0, it means the main process (entrypoint or command) completed its task without errors. Option C is correct because `docker stop` sends a SIGTERM signal to the container's PID 1, allowing it to shut down gracefully; if the process handles the signal and exits cleanly, the exit code will be 0.

Answer

The container ran a task and completed

Answer

The container's entrypoint crashed

Answer

The container ran out of memory

Question 2

A Linux administrator needs to verify which network interfaces are up and their IP addresses on a server. Which command provides this information?

Accepted Answer

ip addr. The `ip addr` command displays all network interfaces along with their IP addresses, MAC addresses, and status (UP/DOWN).

Answer

ss -tlnp

Answer

nmcli dev show

Answer

ifconfig -a

Question 3

An AppArmor profile for a web server is in complain mode. After testing, the administrator wants to enforce the profile. Which command accomplishes this?

Accepted Answer

aa-enforce /etc/apparmor.d/usr.sbin.httpd. The correct command to enforce an AppArmor profile that is currently in complain mode is `aa-enforce`. This command switches the profile from complain (log-only) to enforce (block violations) mode. The option `-r` in `apparmor_parser` reloads the profile but does not change its mode; `aa-complain` sets it to complain mode, and `aa-status` only displays status.

Answer

apparmor_parser -r /etc/apparmor.d/usr.sbin.httpd

Answer

aa-complain /etc/apparmor.d/usr.sbin.httpd

Answer

aa-status /etc/apparmor.d/usr.sbin.httpd

Question 4

A database server running on Linux is experiencing high load. The administrator runs 'strace -p <pid>' and sees many 'epoll_wait' and 'futex' calls. Which THREE of the following are possible causes of the high load? (Choose THREE.)

Accepted Answer

Disk I/O contention causing processes to wait.. 'epoll_wait' indicates the process is waiting for I/O events, and 'futex' calls are used for synchronization. Disk I/O contention can cause the database process to block on these system calls, leading to high load as the kernel schedules other tasks while waiting for I/O to complete.

Answer

CPU frequency scaling is set to powersave.

Answer

A memory leak in the database process.

Question 5

A Linux administrator is creating a shell script to back up configuration files to a remote server. The script must ensure that if any command fails (e.g., rsync or tar), the script exits immediately and does not continue. Which TWO of the following should be included in the script to achieve this behavior? (Choose two.)

Accepted Answer

trap 'exit 1' ERR. `trap 'exit 1' ERR` instructs the shell to execute `exit 1` whenever a command returns a non-zero exit status, which immediately terminates the script on any failure. Option D is correct because `set -e` causes the shell to exit immediately if any command (or pipeline, unless overridden) fails, providing a straightforward way to enforce fail-fast behavior in a backup script.

Answer

set -o pipefail

Answer

set -x

Answer

set -u

Question 6

A container needs to communicate with a database on the host machine using the default bridge network. The container cannot resolve the host by hostname. Which approach should be used?

Accepted Answer

Use --add-host host.docker.internal:host-gateway. `--add-host host.docker.internal:host-gateway` adds a special entry to the container's `/etc/hosts` file that resolves `host.docker.internal` to the host machine's gateway IP address, which on the default bridge network is the host itself. This allows the container to reach the host by a consistent hostname without relying on Docker's internal DNS, which does not resolve hostnames on the default bridge. The `host-gateway` magic value automatically maps to the host's IP (typically 172.17.0.1 on Linux).

Answer

Set --net=host

Answer

Use --link db:db

Answer

Create a custom bridge network

Question 7

Which TWO commands can be used to check disk space usage on a Linux system?

Accepted Answer

du. The `du` (disk usage) command estimates file and directory space usage, allowing you to check disk space consumed by specific paths. The `df` (disk free) command reports the total, used, and available space on mounted filesystems. Both are standard tools for inspecting disk space on Linux systems.

Answer

mount

Answer

lsof

Answer

fdisk

Question 8

A Linux administrator needs to locate all files in /var/log that were modified more than 7 days ago. Which command should be used?

Accepted Answer

find /var/log -mtime +7. The find command with -mtime +7 finds files modified more than 7 days ago. locate uses a database and does not support -mtime; grep is for text search; ls does not filter by modification time.

Answer

grep -mtime +7 /var/log

Answer

ls -mtime +7 /var/log

Answer

locate -mtime +7 /var/log

Question 9

A technician needs to search a log file for lines containing either 'ERROR' or 'FATAL' and display the line numbers. Which command accomplishes this?

Accepted Answer

grep -n -E 'ERROR|FATAL' logfile. grep -n -E 'ERROR|FATAL' logfile uses extended regex with alternation and -n for line numbers. -i ignores case, but the stem does not mention case-insensitive; -v inverts match; -r is recursive.

Answer

grep -v -E 'ERROR|FATAL' logfile

Answer

grep -r -n 'ERROR|FATAL' logfile

Answer

grep -i 'ERROR|FATAL' logfile

Question 10

A user wants to run a command that will continue running even after the user logs out. Which command should be used?

Accepted Answer

nohup command &. nohup makes the command immune to hangups and runs in the background.

Answer

disown command

Answer

command &

Answer

bg command

Question 11

A process is consuming excessive CPU and needs to be terminated immediately. The PID is 1234. Which command will terminate the process with the most forceful signal?

Accepted Answer

kill -9 1234. kill -9 (SIGKILL) forcibly terminates the process. SIGTERM (15) is graceful; SIGHUP (1) reloads config; SIGSTOP (19) suspends.

Answer

kill -15 1234

Answer

kill -1 1234

Answer

kill -19 1234

Question 12

An administrator wants to display only the second field from a colon-delimited file named 'passwd' using a text processing tool. Which command will achieve this?

Accepted Answer

awk -F: '{print $2}' passwd. awk -F: '{print $2}' passwd sets field separator to : and prints second field. cut -d: -f2 also works, but the options include awk. sed is for editing, not field extraction; grep is for pattern matching.

Answer

sed 's/:.*//' passwd

Answer

cut -d: -f2 passwd

Answer

grep -o '^[^:]*:[^:]*' passwd

Question 13

A Linux administrator needs to view real-time information about running processes, including CPU and memory usage. Which TWO commands can be used for this purpose? (Choose two.)

Accepted Answer

top. top and htop provide real-time process information with CPU/memory usage. ps gives a snapshot; kill is for terminating; systemctl manages services.

Answer

ps aux

Answer

systemctl list-units

Answer

kill -l

Question 14

Which command is used to query the status of a service managed by systemd?

Accepted Answer

systemctl status servicename. systemctl status shows whether a service is active, enabled, and recent log entries.

Answer

journalctl -u servicename

Answer

service servicename status

Answer

systemctl list-units --type=service

Question 15

Based on the exhibit, which statement is true about the sshd service?

Accepted Answer

The service is not enabled to start at boot.. The exhibit shows the output of `systemctl status sshd.service`. The line `Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled; vendor preset: enabled)` indicates the service is currently loaded but its enablement state is `disabled`, meaning it is not configured to start automatically at boot. The `Active: active (running)` line with a PID confirms the service is currently running, but the question asks about boot-time behavior, which is governed by the `disabled` state. Therefore, option D is correct.

Answer

The service is masked.

Answer

The service is inactive.

Answer

The service has exited.