If you deal with legacy code you’ve likely found yourself struggling to debug and fix a mysterious, intermittent problem. Along the way you may have discovered some code that didn’t quite make sense.

Many decisions about code branching models are made in the name of managing risk, and teams sometimes pick models that make integration harder in the name of safety. Moving slowly and placing barriers to change can seem safer, but agile teams work best when they acknowledge that there is also risk in deferring change.

Docker containers are launched using Docker images, which are built from layers of Dockerfiles. A Dockerfile is a text document that contains all the commands or instructions to create, copy, and run an image. Let’s look at what goes into creating a Dockerfile, which could be used to build a runnable Docker image.