Docker is everywhere and there are many ways to make Dockerfiles, and many examples, all very simple, with few really good ones around. And the good ones are rarely annotated or explained on why they are good or what you should do. So, this article is about useful standards and guidelines I’ve found useful in creating more complex Dockerfiles and is related to my DockerFile Annotated Example. First, there are some general guidelines, mostly centered around long-standing good engineering practices that also apply to Dockerfiles. They apply here even more so, as a Dockerfile can be a very dynamic file that changes often and over a long time, necessitating serious efforts to make it very high quality at all times.