Platform & DevOps·Packaging: containers and images
you ship a tarball of a whole filesystem plus a line saying what to run, and the same bytes go to every environment.
Container image
Also calledimage, OCI image
The build output a container is started from: a stack of filesystem layers plus a small configuration document naming the entrypoint, environment and working directory. It is the unit that makes 'works on my machine' testable, because the machine travels with the code. The thing people underestimate is that it is a filesystem, not a package — everything the process opens at runtime either has to be in there or has to be mounted in.