How to: Lab 1.7. Container environment variables
1. Run a `mysql` container in detached mode
2. Connect to the container
3. Review the container logs and resolve the output message regarding environment variable
4. Confirm issue resolved by connecting to the container
5. Exit the container
6. List running containers
7. List all containers
8. List all images
9. List all volumes
10. Clean up with [`docker system prune`](https://docs.docker.com/engine/reference/commandline/system_prune/)
11. Check all resources are deleted, containers, images and volumes.
lab1.7 solution
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