XK0-006 Automation, Orchestration, and Scripting Practice Test 3 — 15 Questions

Question 1

A DevOps team is designing a containerized application using Docker Compose. They need to ensure that the database container is started before the application container. Which of the following Docker Compose directives can be used to control startup order? (Choose TWO.)

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

depends_on. depends_on ensures that the specified services are started first. healthcheck can be used to wait for a service to be healthy before starting dependent services.

Answer

volumes

Answer

links

Answer

environment

Question 2

A Linux administrator is writing a bash script that must exit immediately if any command fails. Which of the following should be included at the beginning of the script?

Accepted Answer

set -e. The set -e command causes the shell to exit if any command exits with a non-zero status, which is exactly what is needed to ensure the script stops on failure.

Answer

set -o pipefail

Answer

set -u

Answer

set -x

Question 3

A DevOps engineer needs to run a Docker container in the background with port mapping from host port 8080 to container port 80, and name the container 'webapp'. Which command accomplishes this?

Accepted Answer

docker run -d -p 8080:80 --name webapp nginx. The docker run command with -d (detach), -p (port mapping), and --name options is the correct way to run a container in the background with port mapping and a name.

Answer

docker start -d -p 8080:80 --name webapp nginx

Answer

docker create -d -p 8080:80 --name webapp nginx

Answer

docker compose up -d -p 8080:80 --name webapp nginx

Question 4

An administrator writes a bash script that uses a function to check if a file exists and is readable. The function returns 0 if the file meets the conditions, and 1 otherwise. Which of the following correctly implements this function?

Accepted Answer

check_file() { [[ -f "$1" ]] && [[ -r "$1" ]] && return 0; return 1; }. All four options are functionally correct. Option A chains two [[ ]] tests; Option B chains test commands with && and ||; Option C uses [ -a ]; Option D uses [[ && ]] inside an if statement. Each returns 0 only when the file exists and is readable, and returns 1 otherwise. If a single-answer question is required, the stem should be revised.

Question 5

A system administrator needs to create a Dockerfile for a Python application. The application should be installed in the container, and when the container starts, it should run the command 'python app.py'. Which Dockerfile instruction should be used to specify the default command?

Accepted Answer

CMD python app.py. CMD specifies the default command to run when the container starts. ENTRYPOINT can also be used but is typically for executables that are not easily overridden.

Answer

ENTRYPOINT python app.py

Answer

RUN python app.py

Answer

STARTUP python app.py

Question 6

A Linux administrator is writing a bash script that needs to iterate over all files ending with .log in /var/log and output the number of lines in each file. Which loop construct should be used?

Accepted Answer

for f in /var/log/*.log; do wc -l "$f"; done. A for loop with a glob pattern is the simplest way to iterate over files matching a pattern.

Answer

while read f; do wc -l "$f"; done < /var/log/*.log

Answer

for ((i=0; i<${#files[@]}; i++)); do wc -l "${files[$i]}"; done

Answer

until [ -z "$f" ]; do wc -l "$f"; shift; done

Question 7

A DevOps team is using Ansible to manage configuration of web servers. They need to ensure that the Apache service is running and enabled at boot on all servers in the 'webservers' group. Which playbook task accomplishes this?

Accepted Answer

- name: Ensure Apache is running
  service:
    name: httpd
    state: started
    enabled: yes. The Ansible service module can manage services; the 'enabled' and 'state' parameters control boot status and running state.

Answer

- name: Ensure Apache is running
  systemd:
    name: httpd
    state: started
    enabled: yes

Answer

- name: Ensure Apache is running
  shell: systemctl start httpd && systemctl enable httpd

Answer

- name: Ensure Apache is running
  command: systemctl enable --now httpd

Question 8

A containerized application uses a volume to persist data. The administrator needs to create a new volume named 'data-vol' and mount it to /app/data in the container. Which of the following commands accomplish this? (Select all that apply.)

Accepted Answer

docker run --mount type=volume,source=data-vol,target=/app/data myapp. Both options A and C are correct because they create the volume automatically if it doesn't exist and mount it to the container. The `--mount` flag (option A) uses a more explicit syntax compared to the `-v` flag (option C), but both achieve the same result. Option B is incorrect because the leading slash in `/data-vol` causes a bind mount from the host, not a named volume. Option D is incorrect because it uses two separate commands (`docker volume create` and `docker run`), while the question asks for a single command that both creates and mounts the volume.

Answer

docker run -v /data-vol:/app/data myapp

Answer

docker volume create data-vol && docker run -v data-vol:/app/data myapp

Question 9

A Linux administrator is writing a bash script that accepts command-line options: -a for all, -f for file, and -o for output. Which of the following correctly uses getopts to parse these options?

Accepted Answer

while getopts "afo" opt; do case $opt in a) ...;; f) ...;; o) ...;; esac; done. getopts uses a string of option characters; a colon after an option indicates it requires an argument. The correct usage is 'a:f:o' where a and f require arguments, but the stem doesn't specify arguments. Assuming -a and -f don't require arguments, the string should be 'afo'.

Answer

while getopts "-a -f -o" opt; do ... done

Answer

while getopts "a:f:o" opt; do case $opt in a) ...;; f) ...;; o) ...;; esac; done

Answer

getopts "afo" opt; case $opt in a) ...;; f) ...;; o) ...;; esac

Question 10

In a Kubernetes cluster, a developer needs to create a Deployment that runs three replicas of a container image 'myapp:1.0' and exposes port 8080. Which YAML snippet correctly defines this Deployment?

Accepted Answer

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp:1.0
        ports:
        - containerPort: 8080. A Deployment YAML must have apiVersion, kind, metadata, spec with replicas and template containing container spec with image and ports.

Answer

apiVersion: v1
kind: Pod
metadata:
  name: myapp
spec:
  replicas: 3
  containers:
  - name: myapp
    image: myapp:1.0
    ports:
    - containerPort: 8080

Answer

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    app: myapp
  template:
    containers:
    - name: myapp
      image: myapp:1.0
      ports:
      - containerPort: 8080

Answer

apiVersion: v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  template:
    spec:
      containers:
      - name: myapp
        image: myapp:1.0
        ports:
        - containerPort: 8080

Question 11

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 12

A bash script needs to test whether a string variable $NAME is non-empty and equals 'admin'. Which of the following conditionals is correct?

Accepted Answer

if [[ -n $NAME && $NAME == 'admin' ]]; then. In bash, [[ -n $NAME ]] tests if the string is non-empty, and == compares strings. Using double brackets is safer for string comparison.

Answer

if [[ $NAME -ne '' && $NAME -eq 'admin' ]]; then

Answer

if [ $NAME != '' ] && [ $NAME == 'admin' ]; then

Answer

if [ ! -z $NAME -a $NAME = 'admin' ]; then

Question 13

An administrator needs to create a Docker network of type 'bridge' so that containers can communicate with each other by name. Which command creates a user-defined bridge network named 'my-net'?

Accepted Answer

docker network create -d bridge my-net. User-defined bridge networks provide automatic DNS resolution between containers. The command is 'docker network create' with the -d (driver) flag.

Answer

docker network create my-net

Answer

docker create network -d bridge my-net

Answer

docker network create --driver=overlay my-net

Question 14

A Linux administrator is writing a bash script to process a list of usernames stored in an array. The script must iterate over each username and print a welcome message. Which TWO of the following loops will correctly iterate over the array 'users' and print 'Welcome, <username>'? (Choose TWO.)

Accepted Answer

for ((i=0; i<${#users[@]}; i++)); do echo "Welcome, ${users[$i]}"; done. Arrays can be iterated using for with ${users[@]} or using indices. The correct methods are direct iteration over elements and using a C-style for loop with indices.

Answer

for user in $users; do echo "Welcome, $user"; done

Answer

for user in "${users[*]}"; do echo "Welcome, $user"; done

Answer

while read user; do echo "Welcome, $user"; done < <(printf '%s
' "${users[@]}")

Question 15

A DevOps engineer is creating a Dockerfile for a Node.js application. Which THREE of the following instructions are valid and commonly used in a Dockerfile? (Choose THREE.)

Accepted Answer

COPY . /app. Common Dockerfile instructions include FROM, RUN, COPY, EXPOSE, CMD, ENTRYPOINT, etc. The valid ones here are FROM, RUN, and COPY.

Answer

EXECUTE node app.js

Answer

INSTALL package.json