Docker: images, containers and data
An image is an executable template; a container is a running instance. Data in a deleted container’s writable layer should not be treated as persistent. Databases need persistence such as volumes.
A concrete example
Starting a code execution service locally does not expose it to the Internet. 127.0.0.1 is reachable only from the same machine. Live use also needs a running machine, access control and a secure network path.
image → container; database → volumeExplain it yourself
Why does buying a domain not keep a service running on a powered-off computer?
How to study this
Write your reasoning first. Check the original documentation, identify an assumption, then try a different example. Reading this page does not count as verified skill evidence.
Source and review
Original RealDeveloper explanation; last source check: .