100 Days of DevOps — Day 58-Docker Basics

Welcome to Day 58 of 100 Days of DevOps, Focus for today is Docker Basics

What is a docker?

As per official documentation “Docker is a platform for developers and sysadmins to develop, deploy, and run applications with containers”

Containers are different than Virtual Machines because

• We can start with a small base image instead of the whole operating system
• After that, we can just add an application(and its dependencies)that we need
• Because containers carry its dependencies, the underlying operating system doesn’t need to supply libraries, executables and other components it needs
• Containers are more portable and efficient then Virtual Machine because they eat less memory and storage

Installing Docker on Centos7

• First, update the package database

# yum check-update

• Now run this command, this will install the latest version of official docker repository

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

• Start the docker daemon

# systemctl start docker

• Make sure it start after every reboot

# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.