What is Docker?
Docker is name of a company, which provides host of product like (docker engine etc). Using these we can get OS level virtualization to build, deploy, run, update, and stop containers easily.
Docker provides abstraction and it makes it easier, simpler, and safer to build, deploy and manage multiple containers of different kinds.
What is Container.
Container can be considered as a packages of software, that combines applications and all its dependencies. For e.g : (bootfs (OS) + java + tomcat + application). These containers are independent and reliable across diffent computing environments.
Docker workflow are series of steps to build and publish and image. Docker Deamon running on docker host builds an image based on the configuration of user. This image then gets saved in the Docker registry. Then Docker daemon either creates a new image or pulls an existing image from the Docker registry. Finally, Daemon creates an instance of a Docker image. Using this image a containers can be run.
How container created?
A containers is created using : 1) Ubuntu / Centos os 2) Software required on top of it (Java, PHP, Dotnet etc) 3) Server etc required to run applications like Jboss, Tomcat etc 4) and then we add our applications into it.