Docker Installation:

I use Ubuntu 14.04 VM (4 Core, 16 GB RAM) for practing the Docker.

Docker comes in Two Versions. Community Edition(CE) and Enterprise Edition.(EE).

Lets install CE.

References:

https://docs.docker.com/get-started/

For writing Docker file:

https://docs.docker.com/engine/reference/builder/

Installation:

https://store.docker.com/editions/community/docker-ce-server-ubuntu?tab=description

Extra packages for Ubuntu 14.04

sudo apt-get update
sudo apt-get install \
    linux-image-extra-$(uname -r) \
    linux-image-extra-virtual

Install Docker CE

sudo apt-get update
sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo apt-key fingerprint 0EBFCD88
sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"
sudo apt-get update
sudo apt-get install docker-ce

To verify the docker installation

sudo docker run hello-world

DockerHub:

Create a account in dockerhub. Dockerhub is public docker server to store/retrive the images globally(in web), similar to github which is used for store/retrive code.

docker hub consists of plenty of official opensource projects docker repository, such as nginx, redis, ubuntu,httpd,mongo etc.

To use those images,

• sudo docker pull ubuntu
• sudo docker pull nginx