Docker is an open platform for developing, shipping, and running applications. https://docker.github.io/engine/understanding-docker/

• What it can be used for
  • Fast, consistent delivery of applications
  • Responsive deployment and scaling
  • Running more workloads on the same hardware
• Its architecture
  • Daemon
  • CLI and API
  • Images
  • Containers
  • Registries (Docker Hub)

• Install: From https://docker.github.io/engine/getstarted/linux_install_help/

  curl -fsSL https://get.docker.com/ | sh
  

• Verify installation:

  docker version
  docker run hello-world
  

• Check containers and images:

  docker ps -a
  docker images
  

• Hello world:

  docker run ubuntu:14.04 /bin/echo 'Hello world'
  

• An interactive container:

  docker run -t -i ubuntu:14.04 /bin/bash
  pwd
  ls
  exit
  

• A daemonized hello world:

  docker run -d ubuntu:14.04 \
      /bin/sh -c "while true; do echo hello world; sleep 1; done"
  docker ps
  docker logs -f <name-of-container>
  docker stop <name-of-container>
  docker ps -a
  docker rm <name-of-container>
  

• Create a new container from ubuntu-upstart:

  docker run -d --name=webapp --hostname=example.org \
             -p 80:80 ubuntu-upstart:14.04
  

• Update system packages of the container:

  alias docker-webapp-exec='docker exec -it webapp env TERM=xterm'
  docker-webapp-exec bash
  apt-get update
  apt-get -y upgrade
  

• Install apache2 and mysql:

  apt-get install apache2 mysql-server php5 php5-mysql
  

• Create a test app:

  cd /var/www/html/
  apt-get install vim
  vim index.php
  exit
  

• Add this line on /etc/hosts.

  127.0.0.1 example.org
  

• Try it in browser: http://example.org

docker
docker inspect
docker inspect --help
docker inspect ubuntu-upstart:14.04
docker inspect webapp
docker inspect -f '{ { .NetworkSettings.IPAddress }}' webapp
docker top webapp

Let's see how Docker is used by installing a B-Translator Client: http://info.btr.fs.al/install.html

• Get the image:

  docker search btranslator
  docker pull btranslator/btr_client:v3.0
  docker images
  

• Create and start a container:

  docker create --name=btr_client --hostname=example.org \
      -p 443:443 --restart=always \
      btranslator/btr_client:v3.0
  docker ps
  docker ps -a
  docker start btr_client
  

• Add this line on /etc/hosts.

  127.0.0.1 fr.example.org
  

• Open in browser: https://fr.example.org