https://www.docker.com/

What is docker ?

Docker is a container technology , a tool for creating and managing containers

What’s a container ?

A container in software development is a standardized unit of software, a package of code and dependencies to run that code

The advantage is that the same container always yields the exact same application and execution behavior no watter by whom it might be executed

Docker simplifies the creation and management of these containers

Why containers ?

• Different development & production environments ; we want to build and test in exactly the same environment as we later run our app in
• We want reliability and reproductible environments
• Every team member should have the exactly same environment when working on the same project
• Often tools for project A are different from those of project B

Example of Dockerfile

FROM node:12.16.3
WORKDIR /code
ENV PORT 80
COPY package.json /code/package.json
RUN npm install
COPY . /code
CMD ['node','src/server.js']

// docker build --tag tagName workingDirectory ('.' for current)
docker build --tag hello-world . 

// List of images on your machine
docker images

// docker run options image command arg...
docker run hello-world

// anything is running on our system
docker ps 
// show everything
docker ps -a 
// start
docker start name
// remove
docker rm name