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Blizzard Entertainment·Backend Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say
Jul 2026

Summary

Backend Engineer interview at Blizzard Entertainment with a practical Docker cleanup task. Pretty hands-on, no theory fluff, just show me you can actually use the CLI.

Questions Asked (1)

Q1

Using only the Docker CLI, fully clean up a local Docker environment: stop and remove all running and stopped containers, remove all images, and remove all volumes, so that docker ps -a, docker images -a, and docker volume ls all return empty.

Technical Trade-offsAPI & Integrations
Author's notes

I knew the individual commands but had a moment of second-guessing the order.

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AI HintsAI Generated

Suggested Approach

Start by explaining the order of operations: stop and remove containers first, then remove images, then volumes, because containers can hold references to images and volumes. Use Docker CLI commands with appropriate flags to force removal and avoid prompts. Finally, verify that all resources are cleaned up by running the three listing commands.

Pro tip: Mention that you would use `docker system prune -a --volumes` as a one-liner, but also explain the step-by-step commands to demonstrate deeper understanding and control, especially in production-like environments where you might want to be more careful.

1. Stop and remove all containers

Use `docker stop $(docker ps -aq)` to stop all running containers, then `docker rm $(docker ps -aq)` to remove all containers (including stopped ones). Alternatively, use `docker rm -f $(docker ps -aq)` to force stop and remove in one command.

2. Remove all images

Run `docker rmi $(docker images -aq)` to remove all images. If images are in use by stopped containers, ensure containers are removed first. Use `-f` flag if necessary to force removal.

3. Remove all volumes

Execute `docker volume rm $(docker volume ls -q)` to remove all volumes. Note that volumes in use by containers cannot be removed, so containers must be removed first.

4. Verify cleanup

Run `docker ps -a`, `docker images -a`, and `docker volume ls` to confirm that all three return empty lists. If not, investigate any remaining resources and remove them.

Key Points to Mention

  • Order of operations: containers must be removed before images and volumes because they may reference them.
  • Use of command substitution with `docker ps -aq`, `docker images -aq`, and `docker volume ls -q` to get IDs.
  • The `-f` (force) flag for `docker rm` and `docker rmi` to avoid errors when resources are in use.
  • Potential pitfalls: dangling images, stopped containers, and anonymous volumes might not be removed by simple commands; consider `docker system prune -a --volumes` as a comprehensive cleanup.
  • Verification steps to ensure all resources are removed.
  • Safety considerations: in a shared or production environment, such commands are destructive and should be used with caution; always confirm the environment before running.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.