Tell Module 16/18 learners the container engine/daemon must be running #46

New Issue

2026-06-22T14:24:00-04:00

claude commented

2026-06-22 14:24:00 -04:00

Problem

Module 16 verifies Docker only with docker --version, which succeeds even when Docker Desktop/the engine isn't running. The next command, docker build, then fails with "Cannot connect to the Docker daemon" — confusing for someone who just verified Docker "works." On macOS/Windows this is a near-universal first stumble, and it carries into Module 18's deploy lab. The module is the first-time Docker onboarding ("You do not need Docker installed yet — that's the first step of the lab").

Evidence

modules/16-containers-and-reproducible-environments/README.md "You'll need": "Verify with docker --version"; Part A immediately runs docker build -t tasks-app . with no mention of starting the daemon. No mention of "daemon"/"docker info"/"engine running" in M16 or M18.

Why it matters

"docker --version works but docker build can't connect to the daemon" is the most common first-run Docker failure, and the version check gives false reassurance.

Proposed change

Add a tool-agnostic line (the module is Podman-friendly): "On macOS/Windows, make sure your container engine is running before building (start Docker Desktop, or podman machine start) — docker --version reports the client version even when the engine is stopped; docker info confirms the daemon is up."

Acceptance criteria

Module 16 tells the learner the engine must be running before docker build, and how to confirm (docker info).
The note is engine-agnostic (Docker/Podman).

Affected files

modules/16-containers-and-reproducible-environments/README.md

References

Source finding F57 (realVotes 3/3).

Filed from an adversarial multi-agent course review (217 raw findings → 54 adversarially-verified survivors). Scoped for manual review; intentionally not auto-assigned to an agent.

## Problem Module 16 verifies Docker only with `docker --version`, which succeeds even when Docker Desktop/the engine isn't running. The next command, `docker build`, then fails with "Cannot connect to the Docker daemon" — confusing for someone who just verified Docker "works." On macOS/Windows this is a near-universal first stumble, and it carries into Module 18's deploy lab. The module is the first-time Docker onboarding ("You do not need Docker installed yet — that's the first step of the lab"). ## Evidence `modules/16-containers-and-reproducible-environments/README.md` "You'll need": "Verify with `docker --version`"; Part A immediately runs `docker build -t tasks-app .` with no mention of starting the daemon. No mention of "daemon"/"docker info"/"engine running" in M16 or M18. ## Why it matters "docker --version works but docker build can't connect to the daemon" is the most common first-run Docker failure, and the version check gives false reassurance. ## Proposed change Add a tool-agnostic line (the module is Podman-friendly): "On macOS/Windows, make sure your container engine is running before building (start Docker Desktop, or `podman machine start`) — `docker --version` reports the client version even when the engine is stopped; `docker info` confirms the daemon is up." ## Acceptance criteria - [ ] Module 16 tells the learner the engine must be running before `docker build`, and how to confirm (`docker info`). - [ ] The note is engine-agnostic (Docker/Podman). ## Affected files - `modules/16-containers-and-reproducible-environments/README.md` ## References Source finding F57 (realVotes 3/3). --- *Filed from an adversarial multi-agent course review (217 raw findings → 54 adversarially-verified survivors). Scoped for manual review; intentionally not auto-assigned to an agent.*