Introduction

Docker

• What is Docker
• Why use Docker
• How it works
• Installing Docker
  • Linux
  • Windows
  • Mac
• Using Docker
• Using Docker Compose
• Building an image
• More on Docker command usage
  • Container commands
  • Volume commands
  • Image commands
  • Network commands

• More on building images

  What is Docker

  Docker is program that does operation system level virtualization. It uses containers, which contain the application and all of its tools libraries and configs. Containers are isolated from each other and communicate through well define channels. All the container share a single operating system kernel. This makes the more lightweight than virtual machines. Containers are built from and images which define what the container contains. They normally will use a publicly available base image.

  Why use Docker

A great advantage of docker is that you have development environment that will be identical to the production one. It allows you to easily run multiple version of software with out them interfering with each other. You can easily share a development environment around. It supports all the major operating systems and is easy to install. It is scalable and supports high availability.

How it works

There is a base operating system, be it bare metal or a virtual machine that docker is install on. Containers based of an image will then run on this system. Persistent storage, in the form of a volume or a file system mount can be added. Container run on their own internal networks and need to forward to access the outside world.

Installing Docker

Linux

curl -fsSL curl -fsSL https://get.docker.com | sudo bash - sudo curl -L#1.22.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose` sudo chmod +x /usr/local/bin/docker-compose

Windows

https://docs.docker.com/docker-for-windows/install/

Mac

https://docs.docker.com/docker-for-mac/install/#install-and-run-docker-for-mac

Once it is install open a terminal and run

docker run hello-world

---

Using Docker

This will create a container with the name 'webserver' and will listen to all public interfaces on port 8080 using the nginx image.

docker run --name webserver -p 8080:80 -d nginx

Show running containers

docker ps

Show all containers

docker ps -a

Start Stop

docker start <name/id> docker stop <name/id>

---

Using Docker Compose

Quite often you will need multiple applications, say a web app, a webserver and a database. Managing the separately can be a pain. This is where Docker Compose is use full. It allows you combine multiple containers into stack to make the easier to manage.

version: '3'
services:
  nginx:
    image: jwilder/nginx-proxy
    ports:
      - "80:80"
      - "443:443"
    container_name: nginx
    volumes:
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - nginx-vhost:/etc/nginx/vhost.d
      - nginx-certs:/etc/nginx/certs
      - nginx-html:/usr/share/nginx/html
    restart: unless-stopped

  letsencrypt:
    image: jr
    cs/letsencrypt-nginx-proxy-companion
    container_name: letsencrypt
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - nginx-vhost:/etc/nginx/vhost.d
      - nginx-certs:/etc/nginx/certs
      - nginx-html:/usr/share/nginx/html
    environment: 
      NGINX_PROXY_CONTAINER: nginx
    restart: unless-stopped
    
volumes:
  nginx-vhost:
  nginx-certs:
  nginx-html:
  portainer:

Building an image

FROM python:slim

RUN pip install \
    docker \
    jupyter

COPY docker.ipynb /data/docker.ipynb
COPY *.py /data/
COPY entry.sh /entry.sh

RUN useradd -d /data jupyter \
    && chown -R jupyter:jupyter /data

EXPOSE 8888

VOLUME /data

WORKDIR /data

ENTRYPOINT [ "sh", "/entry.sh" ]

CMD [ "--ip=0.0.0.0", "--NotebookApp.token=''" ]

More on Docker command usage

Container commands

Volume commands

Image commands

Network commands

More on building images