Docker Building images A simple Dockerfile


FROM node:5

The FROM directive specifies an image to start from. Any valid image reference may be used.

WORKDIR /usr/src/app

The WORKDIR directive sets the current working directory inside the container, equivalent to running cd inside the container. (Note: RUN cd will not change the current working directory.)

RUN npm install cowsay knock-knock-jokes

RUN executes the given command inside the container.

COPY cowsay-knockknock.js ./

COPY copies the file or directory specified in the first argument from the build context (the path passed to docker build path) to the location in the container specified by the second argument.

CMD node cowsay-knockknock.js

CMD specifies a command to execute when the image is run and no command is given. It can be overridden by passing a command to docker run.

There are many other instructions and options; see the Dockerfile reference for a complete list.