Chapter 6: Docker Images and Containers
6.8 Troubleshooting table (first week)
| Symptom | Likely cause | What to try |
|---|---|---|
docker: command not found |
Docker not installed / not on PATH | Install per OS or Desktop; reopen terminal |
| Build context huge / slow | Missing .dockerignore |
Ignore .git, deps, logs |
| Container exits immediately | App crash / wrong CMD |
docker logs <name> |
| curl to host port fails | No -p, or app bound to 127.0.0.1 only |
Add -p; listen on 0.0.0.0 |
port is already allocated |
Another process uses host port | ss -tlnp / choose another host port |
| Permission errors on COPY files | Build context paths wrong | Check paths relative to Dockerfile directory |
Practice task
Pick two rows from the table. For each, write the exact command you would run first on your laptop.