The building blocks of a Dockerfile are a dozen or more directives; most of them are a counterpart of the functions of docker run/create flags. Here we list the most essential ones:
- FROM <IMAGE>[:TAG|[@DIGEST]: This is to tell the Docker daemon which image the current Dockerfile is based on. It's also the one and only instruction that must be in a Dockerfile, which means that you can have a Dockerfile that contains only one line. Like all the other image-relevant commands, the tag defaults to the latest if unspecified.
- RUN:
RUN <commands>RUN ["executable", "params", "more params"]
The RUN instruction runs one line of a command at the current cache layer, and commits out the outcome. The main discrepancy between the two ...
