Docker has brought an ease of use without comparison with VMs typically to build native upstream distribution packages. Where before it was needed to launch a complete environment, copy the sources into it, invoke the build tools to create the packages and then copy them back to the host, Docker has made all these steps much easier and straight forward, allowing for more rapid package production and automation. This presentation will show a detailed use case for building packages for the Mageia Linux distribution with bm and mgarepo usages encapsulated in Docker containers. It should help any upstream packager adopt a similar approach to make his packaging task a breathe. Please note that this talk replaces one entitled "Do Linux Distributions Still Matter with Containers?" by Scott McCarty who has sent his apologies but is now unable to attend as he has fallen ill.