ced4568andClaude Sonnet 5
682ef2de47
Adds all 8 ROOT 04 modules (why containers exist, images & containers, Docker CLI, container networking, container storage, Dockerfile & image build, Docker Compose, containers → Kubernetes) — 43 activities, using the nested Docker Engine Phase 6D built and tested. Modules 1, 2, and 8 are conceptual (no lab by design) — the honest bridge module (M8) explicitly names what Kubernetes adds beyond what this course already taught, without re-teaching Kubernetes itself. Adds 5 new hands-on Docker scenarios plus 2 MCQs, all against the real nested Docker Engine: docker-cli-basics (run/exec/inspect a real container), docker-container-networking (a genuine "works internally, unreachable from host" port-publishing failure, diagnosed and fixed by recreating the container with the correct `-p` flag), docker-container-storage (a real destroy/recreate cycle proving named-volume persistence, not just described), docker-build-image (a real Dockerfile, a real build, a real custom image run), and docker-compose-multiservice (a real two-service Compose application with a real published port). All tested end-to-end via the real scenario-validation API, including negative tests. Wires rootnode-containers-assessment (2 required + 4 random-draw scenarios) using the existing Phase 3B assessment engine. This completes the entire ROOT_ Foundations sequence (ROOT 01-04) — see docs/PHASE6E_ROOT_FOUNDATIONS_COMPLETION.md. Co-Authored-By: Claude Sonnet 5 <[email protected]>
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Demonstration: run Creates, exec Reaches In
OBSERVE
$ docker run -d --name web nginx:alpine
$ docker ps --format '{{.Names}}'
web
One container exists.
HYPOTHESIS
Predict: will docker exec web echo hello create a SECOND container?
INSPECT
$ docker exec web echo hello
hello
$ docker ps --format '{{.Names}}'
web
Still exactly one container — exec ran a new command INSIDE the existing one, it never
created anything new.
CHANGE
Now actually run the same image again:
$ docker run -d --name web2 nginx:alpine
$ docker ps --format '{{.Names}}'
web2
web
Now two containers exist — because run, unlike exec, always creates a NEW container.
VERIFY
$ docker logs web | tail -3
$ docker inspect web --format '{{.State.Running}}'
true
Both containers are independent, each with their own logs and state — exactly as Module 2's "one image, many containers" demonstration showed.
Instructor Notes
Demo goal: Directly contrast run and exec's effect on the container COUNT — this is the
most common early confusion and deserves a side-by-side comparison.
Approximate timing: 8 minutes live.
Common mistake to watch for: trying to exec into a container that isn't running yet
(exec requires an ALREADY-running target) — a good moment to connect back to docker ps
first.