7.10 Lab — commands, a name, a volume, one stack

Lab

Use the fences in this chapter. One lab, not a second Compose file.

1. docker ps -a and docker images. Save both tables.
2. docker logs --tail 20 on badge-mysql or on db. Write the ready line or the error.
3. docker network ls. Say which type gives DNS by container name, and which type has no network at all.
4. From inside the API or PHP container, resolve the database by name (getent or the app health that uses that hostname).
5. docker volume inspect on badge-mysql-data or badge-api_pgdata. Write the volume name.
6. docker compose up -d --build with the stack in section 7.5. Curl the API. Insert one row.
7. docker compose down then up -d. Confirm the row is still there.
8. One sentence: why you will not run docker system prune --volumes on this machine.

Practice task

Which volume kind holds MySQL after docker rm, which kind is for code you are editing, and which kind is a secret that disappears when the container stops?