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What is Docker? How is it different from VM?

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Docker is an open-source product that helps deliver software as containers that provide OS-level virtualisation. Containers are isolated environment that contains everything you need to execute your application so that you can execute your application on any operating system. It helps write and productise the code efficiently so that your application can run anywhere on any system, irrespective of the environment.

Docker is a fundamental part of cloud computing and a must-have skill for people working in DevOps. If you are one of them, you should go through our article to get a basic understanding of docker.

Also Read: 5 things you might not know about Kubernetes

Docker vs VM

Dockers provide the OS-level virtualisation so that the software can run anywhere on any system, provided the host supports docker.

A VM (Virtual Machine) provides the environment to run one operating system on top of the existing operating system. You can use two different OS simultaneously on a single system. VMWare and AWS EC2 are some of the famous VM providers.

Virtual machines can be said as the precursor of the docker containers. They sound similar, but they are not the same. Hence, one can get confused between them very easily. Thus, let’s see the difference between Docker and Virtual Machines.

ParametersDockerVirtual Machines
OSAll the docker containers run on the kernel of the host system.Every Virtual Machine runs on its own Operating System on top of the host system.
BootingTakes seconds to instantiate the containers.It takes minutes to boot up.
Version controlThe version of docker images used can be controlled easily.No version control.
SecurityLess secure.More secure, since it is fully isolated.
RAMLow memory usage.High memory usage.

Also Read: How to run Linux on top of Windows using VirtualBox?

Docker: Advantages and Disadvantages

Just like the coin has two sides, everything comes with its pros and cons. The table given below covers the advantages and disadvantages of using Docker.

Each docker container runs separately, and the environment of one is isolated from the other.Platform dependant, i.e. no cross-platform compatibility.
Lightweight, scalable and portable. The docker container can run anywhere — from your local system to the cloud.More suitable for command-line applications. Thus, not good for applications requiring good GUI.
Version Control is present – You can specify which version of the docker image you want to use.No data backup and recovery.
Fast deployments – The docker container contains all the minimal things needed to run the application, and you can run the same docker image on different environments.Docker containers don’t give a bare-metal performance, i.e. there is some overhead present due to the interfacing happening between containers and the host OS.
Cost efficient as it makes development and deployment easier and is resource efficient too.

Also read: 4 ways to fix Docker: Error response from daemon: missing or empty content-length header

Chetali Shah

Chetali Shah

An avid reader and an engineering student. Love to code and read books. Always curious to learn new things :)