Docker

What is a container?

A container is a standard unit of software that encapsulates everything that programmers need to build, ship, and run applications.

What is a `Dockerfile`?

The Dockerfile is a text file that instructs Docker how to build an image.

# Use an official image
FROM node:9.4.0-alpine

# Copies files to the container
COPY app.js .
COPY package.json .

# Runs commands
RUN npm install &&\
   apk update &&\
   apk upgrade

# Make a port available outside the container
EXPOSE 8080

# Run a command when the container lunches
CMD ["node", "app.js"]