Skip to Content
Docker Intermediate: Images and Compose That Survive Real Projects
Intermediate
0 likes
Courses
Docker Intermediate: Images and Compose That Survive Real Projects

Final Check: Docker Intermediate

Fifteen scenario questions across the whole course. If you get twelve or more right, you can build lean images, keep data and secrets safe, wire services together and move images between machines.

15 min DockerSecurityDeployment and ContainersPackaging and Dependencies Intermediate
Prev Next
Fullscreen Share
Course content

Sign in to save your progress.

Course Home
1. A build is slow because the context is large, and the image also contains a .git folder. Which single change helps both problems?
Add .git and the large folders to .dockerignore. Move the Dockerfile to another folder. Use docker run --rm instead of docker build. Add a second COPY line.
2. A script entrypoint.sh starts with #!/bin/sh, ends with exec "$@", and works in the image built on Linux. Built on Windows, the container fails with no such file or directory for /entrypoint.sh, though the file is plainly there. What is the likely cause?
The script is too long for Docker. The file was saved with Windows line endings, so the interpreter name ends with a carriage return and cannot be found. Save it with LF endings. The file is not executable, so Docker shows no such file. exec cannot be used in a script.
3. Which Dockerfile ending lets docker run IMAGE --verbose pass the option to the program called converter?
RUN converter ENTRYPOINT ["converter"] EXPOSE converter CMD ["converter"]
4. You mount a new named volume at /data in your image. The image has /data with the app's default files. A later image version changes those files, but containers still show the old ones. Why?
Docker caches the old image forever. A new empty volume is filled from the image once. After that the volume's content stays, even when the image changes. Volumes cannot be changed by containers. The new image was not pushed.
5. Which place is the best choice for the data folder of a database on Docker Desktop for Windows?
tmpfs, so it is fast. A named volume, because it stays on the Linux side, is faster, and keeps the files out of reach of sync and antivirus tools. A bind mount to your Documents folder, so it is backed up. The container's own writable layer.
6. A container running as user 1000 cannot write to a folder that you bind-mounted from a Linux directory owned by root. Which fix is best?
Set the folder to chmod 777. Use a larger image. Change the folder's owner to 1000, or run the container as the user who owns the folder. Run the container as root and leave the folder alone.
7. From a container on a user-defined network you can reach http://lab-web, but a container on a different network cannot. Which statement describes what happened?
Names only work for the first ten containers. Name lookup only covers networks a container is attached to, so the other container never learned the name. lab-web blocks every container that did not start before it. The second container needs the port published first.
8. You want the web service in Compose reachable only from your own computer. Which port line does that?
"8080:80" "80:8080" expose: 8080 "127.0.0.1:8080:80"
9. In a Compose file, a variable ${API_KEY:?API_KEY is required} is used and API_KEY is not set. What happens when you run docker compose up?
The container starts with an empty API_KEY. Compose asks you to type the value. Compose uses the value from the last run. Compose stops with the message and does not start the containers.
10. Your Compose project has compose.yaml and compose.override.yaml. You run docker compose up with no extra options. Which files are used?
Both. The override file is merged into the base file automatically. Neither, until you set COMPOSE_FILE. Only compose.yaml. Only the override file.
11. Which of these keeps a build token out of the final image and out of the image history?
ARG TOKEN with docker build --build-arg. ENV TOKEN=value in the Dockerfile. COPY token.txt and delete it in the next RUN. A build secret: RUN --mount=type=secret,id=token, with docker build --secret.
12. You pull app:1.4.0 on a server and later find that the running image differs from the one your team tested. What is the safest habit to prevent it?
Deploy app:latest, so you always get the newest. Deploy by digest, or by a version tag that nobody is allowed to move. Use a shorter tag name. Rebuild the image on the server every time.
13. You pushed an image to a registry running in a container on your own computer, and you want to confirm that the push worked before you go to the other computer. What is a simple check?
Ask the registry for its repositories or tags, or pull the image after removing your local copy. Check that docker image ls still shows the image. Delete the registry and push again. Restart Docker Desktop and look for errors.
14. Which statement about Docker Hub is true for the steps in this course?
The course ran the registry steps against a local registry, so the Docker Hub steps are described but were not tested against Hub itself. All Docker Hub commands were run with a real account during the course. You must always use a password, never an access token, for docker login. Docker Hub needs no login to push.
15. You want to paste the output of docker compose config into a support chat so someone can check your file. What should you do first?
Nothing. The command hides secrets automatically. Run docker system prune, so the output is clean. Read it and remove any passwords or tokens, because the command prints the resolved values of your variables. Rename the file to .txt before you paste it.

About

Fifteen scenario questions across the whole course. If you get twelve or more right, you can build lean images, keep data and secrets safe, wire services together and move images between machines.

Duration
15 min
Last update
08/10/2026
Was this helpful?
​ 0 ​ 0

Comments (0)

Sign in to comment

No comments yet.