The putting into containers is a repeatable recipe. One would hope that everything you put in is also built from a repeatable recipe. The point is that you ca

The putting into containers is a repeatable recipe. One would hope that everything you put in is also built from a repeatable recipe. The point is that you can reuse the container - that environment - and know that it was always built the same as any other copy. Because, especially with the way some people use package mangers, those "repeatable" recipes are not always repeatable.