Dockerfile Elements

This lab explains how to use dockerfile to create a docker image. A dockerfile is a text file that contains the commands necessary to create an image using the docker build command. A dockerfile uses these commands to build an image.

ADD

Copy files from a source on the host to the containers own filesystem at the set destination.

CMD

Execute a specific command within the container.

ENTRYPOINT

Set a default application to be used every time a container is created with the image.

ENV

Set environment variables.

EXPOSE

Expose a specific port to enable networking between the container and the outside world.

FROM

Define the base image used to start the build process.

MAINTAINER

Define the full name and email address of the image creator.

RUN

Central executing directive for Dockerfiles.

USER

Set the UID (the username) that will run the container.

VOLUME

Enable access from the container to a directory on the host machine.

WORKDIR

Set the path where the command, defined with CMD, is to be executed.