DevOps with Kubernetes - Second Edition

Writing your first Dockerfile

A Dockerfile consists of a series of text instructions to guide the Docker daemon to form an image, and a Dockerfile must start with the FROM directive. For example, we may have an image built from the following one-liner:

docker commit $(                         \  docker start $(                        \    docker create alpine /bin/sh -c      \      "echo My custom build > /etc/motd" \))

This roughly equates to the following Dockerfile:

FROM alpineRUN echo "My custom build" > /etc/motd

Obviously, building with a Dockerfile is much more concise and precise.

The docker build [OPTIONS] [CONTEXT] command is the only command associated with building tasks. A context can be a local path, URL, or stdin, which denotes the location of the Dockerfile. Once a build is triggered, ...