Developing an application using Ruby on Rails is supposed to be really straightforward. But it turns out that getting all of the versions (e.g., Ruby and gems), as well as all of the dependencies (e.g., databases and HTTP servers) right can be time-consuming and frustrating, particularly for newcomers. And then you have to deal with this once again when you move your application to production, and then deployed to multiple servers. One solution to this problem is to use a virtual machine (VM), or perhaps even a container manager such as Docker. In this talk, Laura Frank describes containers and Docker, the parts of a container, and how containers can help to improve your environment for development and deployment alike. She also distinguishes between VMs and containers, helping us to understand the differences between these virtualization systems.