Docker and Singularity

Docker provides "containerization" for software -- a way to package up a piece of software and all its dependencies, so that it can run the same way on different computers.  It is a promising technology for scientists, both for reproducibility, ease of collaboration, and for running software on different computers (like your laptop and different clusters).  I will go through the why and how of using Docker.  For supercomputers (such as our Symmetry machine), Docker isn't allowed due to security issues, but the Singularity program allows users to run Docker containers, so I'll show you how to run your Docker container on Symmetry using Singularity.