Getting started with docker

Introduction

Docker containers wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries and anything that can be installed on a server. This guarantees that the software will always run the same, regardless of its environment.

Run your first docker container

docker run hello-world

• When you run docker run command
  • Docker engine checks if the image is available or not
  • If image is not available, docker engine will pull from docker registry
  • If image is available, docker engine will run the command locally

How Docker Works?

• Docker is the program that enables containers to be built, shipped and run
• Docker Engine uses Linux Kernel namespaces and control groups

Image Reference: https://docs.docker.com/engine/docker-overview/

Terminology

• Docker Image
  • Read only file with OS, libraries and apps
  • Anyone can create a docker image
  • Images can be stored in Docker hub (default public registry) or private registry
• Docker Container
  • Stateful instance of an image with a writable layer
  • Contains everything needed to run your application
  • Based on one or more images
• Docker Registry
  • Repository of images
• Docker Hub
  • Public docker registry

What is Docker Hub?

• Docker Hub is the public registry that contains a large number of images available for your use

Docker Search

• You can also search through all publicly available images in docker hub

docker search wpscan