200-901 Practice Test 24 — 15 Questions

Question 1

A developer creates a Dockerfile for a Python web application. Which instruction should be used to copy the application source code into the container image?

Accepted Answer

COPY. The COPY instruction copies files or directories from the build context into the container filesystem. RUN executes commands, EXPOSE documents ports, and CMD sets default command.

Answer

CMD

Answer

RUN

Answer

EXPOSE

Question 2

In a Docker Compose file, a service 'web' depends on 'db'. The 'db' service uses a volume to persist data. Which compose key ensures that the database starts before the web service?

Accepted Answer

depends_on. depends_on creates a startup order: Docker Compose starts 'db' before 'web'. It does not wait for 'db' to be ready; that requires healthchecks.

Answer

volumes

Answer

links

Answer

networks

Question 3

A CI/CD pipeline using GitHub Actions needs to build a Docker image and push it to Docker Hub. Which event trigger should be used to run the workflow only when code is pushed to the main branch?

Accepted Answer

on: push: branches: [ main ]. The 'push' event with branch filter triggers on pushes to main. 'pull_request' triggers on PRs, 'release' on releases, 'workflow_dispatch' manual trigger.

Answer

on: workflow_dispatch

Answer

on: release: types: [ published ]

Answer

on: pull_request: branches: [ main ]

Question 4

A developer wants to ensure that a containerized application restarts automatically if it exits with a non-zero code. The application is run using Docker. Which flag should be used?

Accepted Answer

--restart on-failure. The --restart flag with 'on-failure' restarts the container only if it exits with a non-zero code, which indicates an error.

Answer

--restart always

Answer

--restart unless-stopped

Answer

--restart no

Question 5

A Kubernetes Deployment is updated with a new image tag, but the rollout fails. Which kubectl command should be used to view the rollout status and troubleshoot?

Accepted Answer

kubectl rollout status deployment/myapp. kubectl rollout status shows the progress of a rollout, and kubectl rollout history shows revisions.

Answer

kubectl get events

Answer

kubectl describe deployment

Answer

kubectl logs deployment

Question 6

A team uses a Jenkins declarative pipeline to deploy a microservice. The pipeline includes stages: Checkout, Build Docker Image, Run Unit Tests, Push to Registry, Deploy to Staging, and Deploy to Production. Which stage should run immediately after 'Build Docker Image' to ensure code quality before the image is pushed?

Accepted Answer

Run Unit Tests. After building the Docker image, the next logical step is to run unit tests to verify code quality before pushing the image to a registry.

Answer

Deploy to Staging

Answer

Deploy to Production

Answer

Push to Registry

Question 7

Which TWO actions are best practices for managing secrets in a CI/CD pipeline?

Accepted Answer

Store secrets as environment variables from a .env file not committed to version control. Environment variables from .env files not committed, and using a secret vault (like HashiCorp Vault) are recommended. Hardcoding in code, storing in config files in git, and using long-lived passwords are insecure.

Answer

Use long-lived static passwords for service accounts

Answer

Hardcode secrets directly in application code for ease of access

Answer

Store secrets in a configuration file stored in the git repository

Question 8

A developer is using Docker Compose to run a multi-service application. Which THREE keys are valid top-level keys in a docker-compose.yml file? (Choose three.)

Accepted Answer

volumes. Services, networks, and volumes are top-level keys in Docker Compose. Ports is a key within a service definition, not top-level.

Answer

environment

Answer

ports

Question 9

A developer needs to apply a Kubernetes deployment manifest from a file named 'deployment.yaml'. Which kubectl command should be used?

Accepted Answer

kubectl apply -f deployment.yaml. kubectl apply -f creates or updates resources from a file. get, describe, and create are not used for applying manifests.

Answer

kubectl create deployment.yaml

Answer

kubectl describe -f deployment.yaml

Answer

kubectl get -f deployment.yaml

Question 10

A CI/CD pipeline includes stages for code commit, build, unit test, integration test, staging deploy, and production deploy. Which change would best prevent a faulty build from reaching production?

Accepted Answer

Add a manual approval gate before production deploy.. Adding a manual approval gate before the production deploy stage allows a human to verify the build and prevent faulty code from being deployed.

Answer

Remove the integration test stage to speed up the pipeline.

Answer

Use the same environment for testing and production.

Question 11

A developer wants to perform a rolling update of a Kubernetes Deployment. Which command will update the image and initiate the rollout?

Accepted Answer

kubectl set image deployment/myapp myapp=myapp:v2. kubectl set image deployment updates the container image and triggers a rolling update if the deployment strategy is RollingUpdate (default).

Answer

kubectl update deployment myapp --image=myapp:v2

Answer

kubectl edit deployment myapp --image=myapp:v2

Answer

kubectl apply -f deployment.yaml --image=myapp:v2

Question 12

A DevOps engineer runs a container using 'docker run -d -p 8080:80 nginx'. The host firewall blocks incoming traffic on port 8080 from external networks but allows from the local host. Which command would allow the engineer to test the container's web server from the same machine?

Accepted Answer

curl localhost:8080. Since the host firewall allows local traffic, using curl localhost:8080 will reach the container via the mapped port.

Answer

curl 10.0.0.1:8080

Answer

docker exec -it <container> bash

Answer

docker logs <container>

Question 13

Which Docker command is used to view the logs of a running container in real-time?

Accepted Answer

docker logs -f <container>. docker logs -f follows the log output, similar to tail -f.

Answer

docker exec -it <container> tail -f /var/log/app.log

Answer

docker attach <container>

Answer

docker logs <container>

Question 14

A developer is writing a web application and wants to prevent SQL injection attacks. Which coding practice should be followed when constructing SQL queries?

Accepted Answer

Use parameterized queries with prepared statements. Using parameterized queries ensures that user input is treated as data, not executable code, preventing SQL injection.

Answer

Use stored procedures exclusively

Answer

Encode user input with base64 before inserting into SQL

Answer

Concatenate user input directly into SQL statements

Question 15

Which TWO Kubernetes resources are used to provide configuration data to pods? (Choose TWO.)

Accepted Answer

Secret. ConfigMap for non-sensitive data and Secret for sensitive data are both used to inject configuration into pods.

Answer

PersistentVolumeClaim

Answer

Deployment

Answer

Service