LinuxCon + ContainerCon North America 2016

Containers are mostly understood via docker which, up until version 1.9, did not use user namespaces at all. This leads to all sorts of wild assertions about "security problems" with Containers. This talk will remedy that by explaining what namespaces are, how they are used and how to set up unprivileged Containers with the user namespace. Since namespaces are little understood, we'll begin with the history of namespaces, how they work, the difference between label and mapping namespaces and finally how all namespaces interact with user namespaces and how user namespaces can be used both to deprivilege root and give an ordinary user a container they can enter with an unprivileged root. We'll use build Containers as a demonstration of the latter