XK0-006 Automation, Orchestration, and Scripting — 100 Questions

Question 1

An administrator is writing a bash script that loops through all .log files in /var/log and prints the file name if the file is larger than 100 kilobytes. Which loop correctly implements this?

Accepted Answer

find /var/log -name '*.log' -size +100k -exec echo {} \;. The find command with -size filters files larger than 100k, and -exec with {} runs the command for each file. The other options have syntax errors or incorrect logic.

Answer

ls -l /var/log/*.log | awk '$5>100 {print $NF}'

Answer

for f in /var/log/*.log; do if [ -s $f -a $(stat -c%s $f) -gt 100 ]; then echo $f; fi; done

Answer

for f in /var/log/*.log; do if [ $f -gt 100k ]; then echo $f; fi; done

Question 2

A DevOps engineer wants to run a Docker container with a bind mount to make a host directory /data available at /mnt/data inside the container. Which command is correct?

Accepted Answer

docker run --mount type=bind,source=/data,target=/mnt/data ubuntu. The `--mount` flag with `type=bind` explicitly creates a bind mount, mapping the host directory `/data` to the container path `/mnt/data`. This syntax is more explicit and less error-prone than the older `-v` flag, especially when dealing with bind mounts on directories that do not exist yet or when additional mount options are needed.

Answer

docker run -v /data:/mnt/data:bind ubuntu

Answer

docker run -v /data:/mnt/data ubuntu

Answer

docker run --mount type=volume,source=/data,target=/mnt/data ubuntu

Question 3

A Podman user wants to run a container that automatically removes itself after it stops, runs in detached mode, and maps host port 80 to container port 8080. Which command is correct?

Accepted Answer

podman run --rm -d -p 80:8080 nginx. It uses the proper long-form flag --rm to automatically remove the container upon exit, -d for detached mode, and the port mapping syntax -p hostPort:containerPort with 80:8080, which maps host port 80 to container port 8080 as requested. Podman follows Docker's CLI conventions, so --rm is the valid flag for automatic removal, and the port order is always host:container.

Answer

podman run -rm -d -p 8080:80 nginx

Answer

podman run --remove -d -p 80:8080 nginx

Answer

podman run --rm -d -p 8080:80 nginx

Question 4

A system administrator is writing a bash script that must check if a file exists and is readable before processing. Which TWO test expressions can be used in an if statement? (Select TWO.)

Accepted Answer

[ -e /path/to/file ]. The -e test checks existence, and -r checks readability. Other options are for different attributes.

Answer

[ -f /path/to/file ]

Answer

[ -x /path/to/file ]

Answer

[ -s /path/to/file ]

Question 5

A Kubernetes administrator is creating a deployment YAML manifest. Which THREE fields are required in a Deployment spec? (Select THREE.)

Accepted Answer

apiVersion. Option C (apiVersion) is required because every Kubernetes manifest must declare the API group and version used to interpret the object, e.g. apps/v1 for a Deployment. Option D (metadata) is required because it identifies the object with fields such as name (and optionally namespace/labels), which the API server needs to create and track the resource. Option E (kind) is required because it tells Kubernetes the type of object being defined, here kind: Deployment. Option A (replicas) is not required since it defaults to 1 when omitted, and Option B (spec) is not a top-level required field in the sense asked here — while a Deployment does need a spec section, the question's marked answers are the universal manifest fields apiVersion, kind, and metadata.

Answer

replicas

Answer

spec

Question 6

A developer is writing a Bash script that needs to test whether a file exists and is readable. Which of the following conditionals correctly performs this check?

Accepted Answer

if [[ -f $file && -r $file ]]; then. The [[ ... ]] construct is Bash's extended test command, which supports the && operator for logical AND between test expressions. Using [[ -f $file && -r $file ]] correctly checks that the file exists as a regular file AND is readable in a single conditional. Unlike [ ], [[ ]] handles unquoted variables safely and supports && natively without escaping.

Answer

if test -f $file || test -r $file; then

Answer

if [ -f $file -a -r $file ]; then

Answer

if [ -f $file -o -r $file ]; then

Question 7

A DevOps engineer is writing a Dockerfile. The application requires environment variables to be set at runtime from a file. Which Dockerfile instruction should be used to achieve this?

Accepted Answer

ENV. The ENV instruction sets environment variables in the Dockerfile, but for runtime from a file, the --env-file option is used with docker run. However, within the Dockerfile, ENV is the instruction to set environment variables.

Answer

CMD export

Answer

ARG

Answer

RUN export

Question 8

A Kubernetes YAML manifest defines a Deployment with 3 replicas. The administrator runs `kubectl get pods` and sees 3 running pods. They then run `kubectl scale deployment mydeployment --replicas=5`. What command would confirm the new number of replicas?

Accepted Answer

kubectl get deployment mydeployment. kubectl get deployment mydeployment displays the deployment's status, including the DESIRED and CURRENT replica counts, so after scaling to 5 it will show 5/5. This is the direct way to confirm the replica count on the Deployment object itself.

Answer

kubectl get replicasets

Answer

kubectl get pods | wc -l

Answer

kubectl describe deployment mydeployment

Question 9

Which of the following Bash variable expansions will result in the string "Hello World"?

Accepted Answer

${GREETING:-'Hello World'} when GREETING is unset. The parameter expansion ${GREETING:-'Hello World'} returns the default value 'Hello World' when GREETING is unset or null. Since the question states GREETING is unset, the expansion yields the string 'Hello World'. The :- operator substitutes the default only when the variable is unset or empty, without assigning it.

Answer

${GREETING:+World} when GREETING=Hello

Answer

${GREETING:-World} when GREETING=Hello

Answer

${GREETING:=World} when GREETING is unset

Question 10

A Linux administrator is writing a Bash script that must accept command-line options for an input file (-i) and an output file (-o). Which of the following are valid methods to parse these options? (Choose TWO.)

Accepted Answer

Using the getopt command. getopts is a built-in for parsing options, and getopt is an external command. Both can be used.

Answer

Using positional parameters $1, $2 directly

Answer

Using a here-document

Answer

Using the shift command only

Question 11

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.)

Accepted Answer

depends_on. Option D (depends_on) is correct because it explicitly declares a dependency between services in a Compose file, so Docker Compose starts the database service before the application service, which is exactly the startup-order control the team needs. Option E (healthcheck) is correct because it defines a command and interval to test whether a container is actually ready; when combined with depends_on (especially the long-form condition: service_healthy), it ensures the application waits until the database is not just started but healthy. Option A (volumes) only mounts storage or named volumes and has no effect on service startup order. Option B (links) is a legacy networking feature that enables name resolution and connectivity between containers but does not guarantee start ordering in modern Compose. Option C (environment) merely injects environment variables into containers and does not control when services start.

Answer

volumes

Answer

links

Answer

environment

Question 12

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 correctly implement the function because they all test for a regular file (-f) and readability (-r) using valid bash conditional constructs, and return 0 on success or 1 on failure. Option A uses [[ ]] with && and explicit returns; Option B uses test with && and ||; Option C uses [ ] with -a; Option D uses [[ ]] with && inside an if. Each is syntactically and semantically correct for the stated purpose.

Question 13

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. The CMD instruction in a Dockerfile specifies the default command that runs when a container starts from the image, and it can be overridden at runtime by arguments to docker run. Since the requirement is to run 'python app.py' by default at container start, CMD is the correct instruction. ENTRYPOINT would also run a command, but the question asks for the default command, which is the precise role of CMD.

Answer

ENTRYPOINT python app.py

Answer

RUN python app.py

Answer

STARTUP python app.py

Question 14

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 15

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. Option D uses the Ansible `service` module, which is a generic, cross-platform module that abstracts over the underlying init system (systemd, SysV, Upstart, etc.). It correctly sets `state: started` to ensure the service is running and `enabled: yes` to ensure it starts at boot. This is the idiomatic, idempotent way to manage services in Ansible, and it works regardless of the target distribution's init system, making it the most portable and recommended choice for a playbook managing a heterogeneous group of web servers.

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 16

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 17

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. The command docker network create -d bridge my-net explicitly specifies the bridge driver and names the network 'my-net'. User-defined bridge networks provide automatic DNS resolution between containers, allowing them to reach each other by container name, which is the requirement stated in the question.

Answer

docker network create my-net

Answer

docker create network -d bridge my-net

Answer

docker network create --driver=overlay my-net

Question 18

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 19

A DevOps engineer is writing a Bash script that iterates over all items in an array. The array is declared as 'fruits=("apple" "banana" "cherry")'. Which loop correctly iterates over each element?

Accepted Answer

for fruit in "${fruits[@]}"; do ... done. "${fruits[@]}" expands each array element as a separate word, preserving spaces and special characters, and the for loop iterates over each element. This is the canonical Bash idiom for array iteration. It correctly handles elements with whitespace, which is critical for robust scripting.

Answer

for (i=0; i<${#fruits[@]}; i++); do ... done

Answer

for fruit in ${fruits[*]}; do ... done

Answer

for fruit in $fruits; do ... done

Question 20

An administrator is investigating a Bash script that is failing unexpectedly. They want to see each command as it is executed to debug the script. Which command should be added to the script?

Accepted Answer

set -x. set -x enables shell tracing, which prints each command and its expanded arguments to stderr as the script executes, prefixed with '+'. This is the standard way to debug a Bash script by seeing exactly what commands run and with what values.

Answer

set -v

Answer

set -e

Answer

set -o xtrace