# Guided Exercise: Trace the Counts Through a Sequence of Commands

This is a paper exercise — commit to your answer before checking it in the Lab.

## Your task

Starting from a completely clean system (no images, no containers), predict the number of
IMAGES and the number of CONTAINERS after each step:

1. `docker pull redis:alpine`
2. `docker run -d --name cache1 redis:alpine`
3. `docker run -d --name cache2 redis:alpine`
4. `docker rm -f cache1`
5. `docker rmi redis:alpine` (attempted while `cache2` is still running)

## A worked shape to check yourself against

1. 1 image, 0 containers.
2. 1 image, 1 container.
3. 1 image, 2 containers.
4. 1 image, 1 container (only `cache1` removed).
5. This actually FAILS — Docker refuses to remove an image that a running container (`cache2`)
   still depends on, specifically to prevent exactly this kind of accident. Still 1 image, 1
   container, plus an error message.

## Instructor Notes

**Facilitation:** Item 5 is the most valuable one — many students haven't seen Docker's
dependency-protection behavior yet, and it's a good real safety feature to highlight.

**Approximate timing:** 8-10 minutes live discussion; 5 minutes self-paced.