In honor of November, which used to be my NaBloWriMo (“National” Blog Writing Month), I’m determined to exceed my usual output of zero posts per month.

A haphazard introduction to Docker

My latest hobby project has been changing this website to use Docker. For anyone who doesn’t know, Docker is a containerization system, which means that it lets you run programs in their own individual “containers” that prevent them from interacting with other programs running on the same computer (except when you specifically allow it). For example, a file stored in a container is typically accessible only within that container, each container has its own set of network ports to send and receive communication, and so on. Containers are a lot like virtual machines, but whereas a virtual machine runs an entire operating system — that includes a kernel plus any number of programs — Docker runs only one primary program in each isolated environment, and when that program needs a kernel to do something like reading data from a file, it uses the underlying host system’s kernel. So you might think of containers as “partly-virtual machines”.

The isolated environment of a container works the other way around, too …