Docker vs. Virtual Machine: Differences You Need to Know

Centuries back, organizations were looking forward to transforming their work with advanced technology as a whole faced constraint by various software, cloud, and on-premises-based infrastructure. Years later, Docker and Virtual Machines were introduced to solve these organizational challenges with a container platform. These software platforms simplify the deployment process of applications and microservices.

Let's see the differences between Docker and VM in order to decide the suitable tool for your organization. Stated below are the topics that we will cover in this article:

  • What is Docker?
  • What is a virtual machine?
  • Docker vs. Virtual machine
  • Key differences: Docker vs. Virtual machine
  • A real-life use-case of Docker
  • Which is a better choice? Docker vs. Virtual Machine

Before we start with the Docker vs. Virtual Machines comparisons, let's have a quick warm-up on these tools.

What is Docker?

Docker is popular virtualization software that helps its users in developing, deploying, monitoring, and running applications in a Docker Container with all their dependencies.

Docker containers include all dependencies (frameworks, libraries, etc.) to run an application in an efficient and bug-free manner.

Docker Containers have the following benefits: 

  • Light-weight
  • Applications run in isolation
  • Occupies less space
  • Easily portable and highly secure
  • Short boot-up time

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What is a Virtual Machine?

A virtual machine (VM) is a computing environment or software that aids developers to access an operating system via a physical machine.

Now, let’s dig into the concept of Docker vs. virtual machine.

Docker vs. Virtual Machine

Depicted below is a diagrammatic representation of how an application looks when deployed on Docker and virtual machines:

docker-vm

Now, let's have a look at the primary differences between Docker and virtual machines.

Differences Docker  Virtual Machine
Operating system

Docker is a container-based model where containers are software packages used for executing an application on any operating system

In Docker, the containers share the host OS kernel

Here, multiple workloads can run on a single OS

It is not a container-based model; they use user space along with the kernel space of an OS

It does not share the host kernel

Each workload needs a complete OS or hypervisor 

Performance

Docker containers result in high-performance as they use the same operating system with no additional software (like hypervisor)

Docker containers can start up quickly and result in less boot-up time

Since VM uses a separate OS; it causes more resources to be used

Virtual machines don’t start quickly and lead to poor performance

Portability

With docker containers, users can create an application and store it into a container image. Then, he/she can run it across any host environment

Docker container is smaller than VMs, because of which the process of transferring files on the host’s filesystem is easier

It has known portability issues. VMs don’t have a central hub and it requires more memory space to store data

While transferring files, VMs should have a copy of the OS and its dependencies because of which image size is increased and becomes a tedious process to share data

Speed

The application in Docker containers starts with no delay since the OS is already up and running

These containers were basically designed to save time in the deployment process of an application

It takes a much longer time than it takes for a container to run applications

To deploy a single application, Virtual Machines need to start the entire OS, which would cause a full boot process

Key Difference: Docker and Virtual Machine

There are many analogies of Docker and virtual machines. Docker containers and virtual machines differ in many ways; let's discuss one analogy using apartment vs. bungalow.

Apartment (Eg: Containers)

Virtual machine (Eg: Bungalow)

Most amenities (binary and library) are shared with neighbors (applications)

Amenities (binary and library) cannot be shared with neighbors (applications)

Can have multiple tenants (Applications)

Cannot have multiple tenants (application)

For a more in-depth understanding, we will look at the key differences between the two below:

Docker

Virtual machine

Containers stop working when the “stop command” is executed

Virtual machines are always in the running state 

It has lots of snapshots as it builds images upon the layers

Doesn’t comprise many snapshots

Images can be version controlled; they have a local registry called Docker hub

VM doesn’t have a central hub; they are not version controlled

It can run multiple containers on a system

It can run only a limited number of VMs on a system

It can start multiple containers at a time on the Docker engine

It can start only a single VM on a VMX

Next, let’s have a look at a real-life use-case of Docker using the BBC news channel.

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A Real-Life Use-Case of Docker

BBC is a British news channel with over 500 developers working across the globe. Let’s move forward and understand what issues the company had and how Docker resolved them.

Challenges

  • BBC uses several languages in different areas of the world because of which it consists of over 10 Continuous Integrations
  • The company had to identify a way to unify the coding processes and monitor the Continuous Integration consistently
  • Also, the existing jobs took up to 60 minutes to schedule and perform its task  

Solution

  • With the help of containers, the developers were able to work in flexible CI environments
  • Entire code processes were unified and stored in a single place for easy and quick access
  • Docker helped in eliminating job wait time and resulted in speeding up the entire process. 

Docker vs. Virtual Machine: Which is a Better Choice?

A lot of people have this question, but the answer to this so far cannot be ascertained, but depending upon their configurations and advantages we could say that containers are overcoming virtual machines. The famous global researcher Gartner has predicted that by 2023, more than 50% of companies will adopt Docker containers. However, a serverless container like Docker will have a raise in the revenue from a small base of $465.8 million in 2020 to $944 million in 2024. 

Enroll for the Docker Certified Associate Training Course to learn the core Docker technologies like the Docker Containers, Docker Compose, and more.

Conclusion

That concludes the Docker vs. VM article. In this write-up, we learned what Docker and Virtual machine are, the differences between Docker and virtual machine, and real-life use case of Docker using BBC

If you'd like to get a good understanding of the Docker tool, Simplilearn can solve your problem. The Docker In-Depth Training Course will help you learn all about Docker. With this certification, you will be able to learn hands-on experience on how to create flexible application environments with Docker.

Do you have any queries for us on this topic? Please feel free to put it in the comments section of this article, our experts will get back to you at the earliest!

About the Author

Sana AfreenSana Afreen

Sana Afreen is a Senior Research Analyst at Simplilearn and works on several latest technologies. She holds a degree in B. Tech Computer Science. She has also achieved certification in Advanced SEO. Sana likes to explore new places for their cultures, traditions, and cuisines.

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