dockerfile cheatsheet 1

Dockerfile cheatsheet 1

Dockerfile reference

Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.

Dockerfile reference

Usage

The docker build command builds an image from a Dockerfile and a context. The build’s context is the files at a specified location PATH or URL. The PATH is a directory on your local filesystem. The URL is a the location of a Git repository.

A context is processed recursively. So, a PATH includes any subdirectories and the URL includes the repository and its submodules. A simple build command that uses the current directory as context:

Inheritance

FROM ruby:2.2.2

Variables

ENV APP_HOME /myapp
RUN mkdir $APP_HOME

Initialization

RUN bundle install

WORKDIR /myapp

Referance:

Dockerfile reference: