Dockerfile

Check out https://hub.docker.com/search/?type=image for bases

Dockerfile

A Docker image consists of read-only layers each of which represents a Dockerfile instruction

# Use an official Python runtime as a parent image
FROM python:2.7-slim

# Set the working directory to /app
WORKDIR /app

# Copy the current directory contents into the container at /app
ADD . /app

# Install any needed packages specified in requirements.txt
RUN pip install --trusted-host pypi.python.org -r requirements.txt

# Make port 80 available to the world outside this container
EXPOSE 80

# Define environment variable
ENV NAME World

# Run app.py when the container launches
CMD ["python", "app.py"]

Commands

ADD
COPY
ENV
EXPOSE
FROM
LABEL
STOPSIGNAL
USER
VOLUME
WORKDIR

Use env variables you declare with env like $foo

RUn

RUN has 2 forms:

• RUN <command> (shell form, the command is run in a shell, which by default is /bin/sh -c on Linux or cmd /S /C on Windows)

• RUN ["executable", "param1", "param2"] (exec form)

RUN mkdir -p /usr/src/things \ #multiple line syntax
  && curl -SL http://example.com/big.tar.gz

CMD

The CMD instruction has three forms:

• CMD ["executable","param1","param2"] (exec form, this is the preferred form)

• CMD ["param1","param2"] (as default parameters to ENTRYPOINT)

• CMD command param1 param2 (shell form)

There can only be one CMD instruction in a Dockerfile. If you list more than one CMD then only the last CMDwill take effec

ENV

ENV myName="John Doe"

ADD

ADD test relativeDir/          # adds "test" to `WORKDIR`/relativeDir/
ADD test /absoluteDir/         # adds "test" to /absoluteDir/

COPY

Like ADD, but without urls and tar handling, should be used when you dont need ADD

Dockerignore

Add things to .dockerignore file to prevent copying

node_modules
npm-debug.log