What is Docker and Why is it Used?

February 23,2020 - 9 min read
What is Docker and why is it used?

Docker is an open-source project which launched in 2013. Docker was monumental in popularizing the technology of containers and microservices in software development. The technology of containers had been around for some time but Docker helped start the trend of cloud native development.

Docker can be defined as a software platform that is used to build applications based on containers. In case you are unaware of the meaning of containers in software development, you may proceed to the next segment where we explain the term containers.


Containers are small and lightweight execution environments. They share the use of the operating system kernel but the applications run in isolation from one another.

In modern software development, developers try to cluster isolated from each other. The main aim of doing so is to prevent the unduly interference of one application with another application’s operation and maintenance. Packages, libraries, and other software components required for an application to run make it difficult for developers to achieve this level of isolation.

This is where Virtual Machines come into the picture. Virtual Machines keep many applications on the same hardware but are entirely separate from each other. This reduces conflicts among the software components of applications and also minimises the competition for hardware resources. Virtual Machines seemed to be the perfect solution however, there are a few disadvantages of this technology too. One of the biggest cons of using virtual machines is that they are bulky as each VM requires its own Operating System. Hence, Virtual machines are difficult to upgrade and even maintain as the size is typically in gigabytes.

A better option is Containers. They isolate the applications’ execution environments from one another. In containers, the use of the operating system kernel is shared. Advantages of containers over Virtual machines are that containers are generally measured in megabytes and they use fewer resources as compared to Virtual Machines. Containers also startup immediately and can be packed far more densely on the same hardware.

With containers, there is an efficient mechanism that updates, maintains and combi0nes software components into application and service stacks that are required in a modern enterprise.

Now that we have briefly understood the concept of containers in application development, let’s proceed to the next segment where we answer the question, what is Docker?

What is Docker?

As mentioned above, Docker is software that makes it easy to create containers and applications based on containers. It originally worked only for Linux, but currently runs on Windows and MacOS also.

The basic concept of Docker is defined however, it’s not enough to comprehend the concept in detail and even work with it. We are now going to have a brief look at the working of Docker by understanding some of the components used in creating Docker-containerized applications. Let’s get started!

  1. Docker Hub

    It’s easy to build containers but you will not need to build all the images from scratch as Docker Hub is here to make your life easy! It is basically a SaaS repository. It is used to share and manage containers. In this repository, one would find official Docker images from different open-source projects and even a few unofficial images from developers, technocrats and learners of technology like you.

    These container images with good and useful code can be downloaded or you can even upload your own on the repository.

  2. Docker Engine

    Docker Engine forms the core component of all software development in Docker. The Docker engine is client-server technology that creates and even runs the containers. Docker engines are the most important in the entire technology of Docker, when one talks about Docker, they are basically referring to Docker Engine. Docker Engine Enterprise and Docker Engine Community are the two versions of Docker Engine available at present.

  3. Dockerfile

    A Dockerfile is basically a text file that is present at the beginning of every Docker container starts with a Dockerfile. The syntax of a Dockerfile is easy-to-understand, it has the instructions to build a Docker image and also specifies the particular operating system. It also contains language, environmental variables, file locations, network ports, and other required components. It also contains the specific functioning of the container once the developers run it.

  4. Docker image

    After the Dockerfile is written, the Docker is invoked in order to create an image based on the Dockerfile. As mentioned above, a Dockerfile is a set of instructions that instructs the build to make the image, a Docker image, on the other hand, contains the specifications for the type of software components used to run a container and its procedure. Docker image is a portable file. Dockerfile includes instructions about software packages but you should be careful enough to specify the proper versions of these software packages in order to prevent the Dockerfile from producing inconsistent images.

  5. Docker run

    It is the command that actually launches a container containing an instance of an image. Containers are temporary, they can be stopped and restarted. If you restart a container, the container launches into the same state as when it was stopped. Also, multiple instances of containers of the same image can run simultaneously as long as each of them has a unique name.

    Now that we have understood the basic concept of Docker, it’s time to read about why Docker is used and how it is popular in the world of containers.

Why is Docker Used?

As mentioned above, containers separate applications from operating systems. Developers can make use of a clean and minimal Linux operating system and hence run everything else in one or more isolated container(s). The container can move across any Linux server that supports the runtime environment of the particular container as the operating system is abstracted away from containers.

However, Docker introduced several significant changes to Linux Container. It makes containers more portable and flexible to use. With Docker, one can deploy, replicate or move a workload more quickly and easily compared to virtual machines.

The image tools of Docker container are advanced as compared to Linux container and hence it is easy for developers to build libraries of images and compose applications. It is also easy to launch containers and applications on local or remote infrastructure.

Another advantage of Docker is that they easily coordinate behaviours between containers. It builds application stacks by getting different containers together. Docker Compose is a command-line tool that makes the process of developing and testing multi-container applications easier and more efficient.

It is widely preferred to Develop applications with Docker as it simplifies and accelerates the workflow. It gives developers flexibility as well as freedom so that they can innovate with tools, application stacks, deployment environments and other variables for their project. In today’s time developing applications is not only about writing code. There are a lot of other complexities like multiple languages, frameworks, architectures among others and Docker simplifies this entire process.

Containers were just the beginning of a disruptive trend, and in 2013 Docker became the industry standard for containers. Containers are a standardized solution to the problem of working only on one machine. Docker has become a popular standard to build and share containerized applications and software from one machine to the cloud.

Docker basically helps developers fight off the usual complexity of an application. With its friendly, CLI-based workflow, Docker makes it simple for containerized applications to build, share, and run by developers of varying skill levels.

With Docker, the entire workflow of an application is simple and fast. All you need to do is install from a single package, code and test locally and ensure consistency between the development and production of applications.

Collaboration is also very easy while developing applications on Docker. You can use certified images provided by the community in your project and even push projects to a cloud-based applications in order to collaborate with team members.

Docker is built by developers in order to make the developers’ lives easier. We have Docker tools that improve development workflows. It has an industry standard for containerizing software and applications.

The blog above was a compilation of the explanation of the concept of Docker and why is it used by developers across the globe. If you have a doubt or a query regarding the technology of containers and Dockers, you can always get in touch with team Konfinity. We wish you all the luck in your journey in technology

Containers are about application deployment, however, if you wish to learn more about web application development, we suggest you take a professional web development. There are a lot of courses available out there but you should choose the one that perfectly suits your needs and requirements. The course you enrol in should encourage you to make projects and build a competitive portfolio that helps you get a job as web developer in your dream company.

Containers are about application deployment, however if you wish to learn more about web application development, we suggest you to take a professional web development. There are a lot of courses available out there but you should choose the one that perfectly suits your needs and requirements. The course you enrol in should encourage to make projects and build a competitive portfolio that helps you get a job as web developer in your dream company.

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