Docker Tutorial

Introduction

Virtual Machine VS Container

Virtual Machine

A virtual machine is a software computer, which acts as a physical computer with an operating system and applications. In other words a computer within a computer. There is a host operating system and, on top of that a hypervisor. Hypervisor is a software, firmware or hardware that creates and runs virtual machines.

Advantages of VMs:

• Multiple OS can exist in same machine simultaneously.
• Flexible
• Very mature

Disadvantages of VMs:

• Not efficient
• Difficult for fast deployment

Container

Container is a new form of visualization. Unlike VMs, containers share same resources of the host OS. Containers sit on top of a physical server and its host OS. Each container shares the host OS kernel and, usually, the binaries and libraries, too.

Advantages of containers:

• Lightweight
• Easy to start — only few seconds
• Less OS maintenance
• Efficient

Disadvantages of containers:

• Cannot run a container with a guest operating system that differs from the host OS because of the shared kernel