XK0-006 Practice Test 18 — 15 Questions

Question 1

A technician suspects a process is leaking file descriptors. Which command can be used to list open files associated with a specific PID?

Accepted Answer

lsof -p PID. lsof -p PID lists open files for that process. strace traces system calls, ltrace library calls, and top shows resource usage.

Answer

top -p PID

Answer

strace -p PID

Answer

ltrace -p PID

Question 2

A cloud engineer is using Ansible to manage configuration across multiple servers. The engineer needs to store variable data that is specific to each host and sensitive database passwords. Which two Ansible features should be used for these purposes? (Choose two.)

Accepted Answer

Ansible Vault. host_vars are used for host-specific variables, and Ansible Vault encrypts sensitive data like passwords.

Answer

group_vars

Answer

ansible_facts

Answer

roles

Question 3

A Bash script contains the following code: if [[ $# -eq 0 ]]; then echo 'No arguments'; fi. What does this code check?

Accepted Answer

Whether the script was called with no arguments. The $# variable holds the number of positional parameters passed to the script. The condition checks if it equals 0, meaning no arguments were provided.

Answer

Whether the first argument is empty

Answer

Whether the script has any syntax errors

Answer

Whether the script is running as root

Question 4

An administrator needs to deploy a set of microservices using Docker Compose. The services require configuration values that vary between development and production environments. Which approach allows the administrator to override values without modifying the docker-compose.yml file?

Accepted Answer

Use multiple compose files with the -f flag: docker-compose -f docker-compose.yml -f docker-compose.prod.yml up.. Docker Compose supports multiple compose files; using multiple -f options allows overriding values from the base file. Environment-specific files like docker-compose.override.yml are automatically used if present, but using explicit -f options is more flexible for different environments.

Answer

Define multiple services in one docker-compose.yml and use profiles.

Answer

Use environment variables in the Dockerfile and pass them via docker run -e.

Answer

Use the extends keyword in docker-compose.yml.

Question 5

After a kernel panic, the system fails to boot. The administrator suspects a missing kernel module. Which command line should be added to the GRUB boot parameters to access a rescue shell and investigate?

Accepted Answer

rd.break. Adding 'rd.break' breaks before pivot_root and drops to a shell for troubleshooting. 'single' boots to single-user mode but may not help if module is missing. 'emergency' is for systemd targets.

Answer

systemd.unit=emergency.target

Answer

single

Answer

nomodeset

Question 6

A developer creates a Dockerfile for a web application. Which instruction should be used to define the command that runs when the container starts, allowing the container to accept arguments from the docker run command?

Accepted Answer

CMD. CMD provides defaults for an executing container, but can be overridden by command-line arguments. ENTRYPOINT is used for main command and CMD for default arguments.

Answer

START

Answer

ENTRYPOINT

Answer

RUN

Question 7

A Docker container needs persistent storage that survives container restarts. Which of the following is the recommended method to achieve this?

Accepted Answer

Use a Docker volume. Docker volumes are managed by Docker and are the recommended way to persist data, as they are independent of container lifecycle.

Answer

Store data inside the container filesystem

Answer

Use a bind mount only for configuration files

Answer

Set the container to always restart

Question 8

After modifying the network configuration on a RHEL 8 system, the administrator wants to bring up the interface without rebooting. Which command sequence should be used?

Accepted Answer

nmcli con up eth0. nmcli con up ifcfg-eth0 activates the connection. If using legacy scripts, ifup eth0 would work, but nmcli is the modern method for NetworkManager.

Answer

ip link set eth0 up

Answer

systemctl restart network && nmcli dev connect eth0

Answer

ifconfig eth0 up

Question 9

A user wants to execute a command inside a running Docker container named 'db'. Which command should be used?

Accepted Answer

docker exec -it db bash. docker exec is used to run a command in an existing running container.

Answer

docker attach db

Answer

docker start -i db

Answer

docker run -it db bash

Question 10

A server running RHEL 8 fails to boot with a 'Dependency failed for /data' error. The /data filesystem is an ext4 partition on /dev/sdb1. Which sequence of steps should be taken to repair the filesystem?

Accepted Answer

Boot into rescue mode, run 'umount /dev/sdb1', then 'fsck.ext4 -f /dev/sdb1'. To repair a filesystem, it must be unmounted; using a rescue environment (e.g., systemd emergency target) ensures the partition is not in use.

Answer

Use 'xfs_repair /dev/sdb1' since it's ext4

Answer

Run 'fsck.ext4 -f /dev/sdb1' from the running system

Answer

Remount the filesystem as read-only and run fsck

Question 11

An administrator is troubleshooting a DNS issue and needs to query the authoritative name servers for example.com. Which dig command should be used?

Accepted Answer

dig example.com NS. dig example.com NS queries the name servers (NS records). A asks for IPv4, MX for mail, and ANY is often blocked.

Answer

dig example.com MX

Answer

dig example.com A

Answer

dig example.com ANY

Question 12

A server is unable to resolve hostnames via DNS. The /etc/resolv.conf file appears correct. Which command can be used to test DNS resolution and display the full query path?

Accepted Answer

dig +trace example.com. The `dig +trace example.com` command performs a full iterative DNS resolution from the root nameservers down to the authoritative nameservers for the queried domain, displaying each step of the query path. This is the correct choice because the question specifically asks to 'display the full query path,' which `+trace` provides by following referrals step by step, unlike simpler queries that only show the final answer.

Answer

nslookup example.com

Answer

host example.com

Answer

resolvectl query example.com

Question 13

A server fails to boot with a kernel panic after a system update. The administrator suspects a corrupt initramfs. Which GRUB boot parameter should be added temporarily to boot into an emergency shell where the filesystem can be repaired?

Accepted Answer

rd.break. The `rd.break` parameter causes systemd to break before the initramfs transitions to the real root, providing an emergency shell for repair. 'single' boots to single-user mode but requires a working initramfs.

Answer

emergency

Answer

single

Answer

nomodeset

Question 14

An administrator is investigating a network issue where a server cannot connect to an external website. They run `ping 8.8.8.8` successfully, but `ping google.com` fails. Which TWO of the following are the most likely causes? (Choose TWO.)

Accepted Answer

The DNS server is unreachable or misconfigured.. Successful ping to IP but failure to hostname indicates DNS resolution problem or incorrect DNS server configuration.

Answer

The network interface is down.

Answer

The default gateway is misconfigured.

Answer

The firewall is blocking ICMP traffic.

Question 15

A user cannot access a website, but other websites work. The administrator wants to see the HTTP response headers from the web server. Which command is most appropriate?

Accepted Answer

curl -I https://example.com. curl -I fetches the HTTP headers only, which is useful for debugging web server responses.

Answer

wget --spider https://example.com

Answer

curl -v https://example.com

Answer

telnet example.com 80