System prune for cleanup in Docker - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the docker system prune command do?

It removes all unused data like stopped containers, unused networks, dangling images, and build cache to free up disk space.

beginner

How can you run docker system prune without being asked for confirmation?

Use the -f or --force flag to skip the confirmation prompt.

intermediate

What is the difference between docker system prune and docker system prune -a?

docker system prune removes dangling images, while docker system prune -a removes all unused images, not just dangling ones.

intermediate

Why should you be careful when using docker system prune -a?

Because it deletes all unused images, including those not currently used by containers, which might be needed later.

beginner

Which Docker objects are cleaned up by docker system prune?

Stopped containers, unused networks, dangling images, and build cache.

What does docker system prune remove by default?

A Only volumes

B Stopped containers, unused networks, dangling images, and build cache

C Only running containers

D All images and containers

docker system prune removes stopped containers, unused networks, dangling images, and build cache by default.

How do you force docker system prune to run without confirmation?

A -q

B -y

C --no-confirm

D -f or --force

The -f or --force flag skips the confirmation prompt.

What extra cleanup does docker system prune -a perform compared to docker system prune?

A Removes running containers

B Removes volumes

C Removes all unused images, not just dangling ones

D Removes only build cache

The -a flag removes all unused images, not just dangling images.

Which Docker objects are NOT removed by docker system prune by default?

A Volumes

B Stopped containers

C Unused networks

D Dangling images

Volumes are not removed by default with docker system prune.

Why might you avoid running docker system prune -a carelessly?

A It deletes unused images that might be needed later

B It deletes running containers

C It deletes volumes automatically

D It stops Docker service

Because it deletes all unused images, which might be important for future use.

Explain what docker system prune does and when you might use it.

Think about cleaning up unused Docker resources to save space.

Describe the difference between docker system prune and docker system prune -a and why the latter requires caution.

Consider what images are removed and the impact on your Docker environment.