Why is Docker used?

Docker is an open platform for developing, shipping, and running applications using containers. Containers allow developers to package an application with all of the parts it needs, such as libraries and dependencies, and ship it as one package.

Why is Docker used?

Using Docker offers several key advantages:

Flexibility and Portability

  • Docker containers are lightweight, standalone executable packages that can run on any system, unlike virtual machines that require an entire guest operating system. This makes Docker very flexible and portable.
  • You can run Docker containers on your local machine, on physical or virtual machines in a data center, on cloud providers, or in a mix of environments. The same container will run seamlessly on any infrastructure.

Faster Application Delivery

  • With Docker, you can quickly setup a standardized and reproducible environment to build, test, and deploy applications. This accelerates app delivery from weeks to days or even hours.
  • No need to deal with inconsistencies between development, test, and production. The same container used in dev and test can go straight to production.

Greater Scalability

  • Docker is designed to take advantage of a microservices architecture where applications are broken down into smaller, composable pieces.
  • Easily scale applications up and down by running more or fewer container instances. This level of flexibility is harder to achieve with VMs.

Greater Resource Efficiency

  • Containers share the host system kernel and only require the app and its dependencies to run. They are thus extremely lightweight and resource efficient.
  • You can get much higher density and run more containers than VMs per host using fewer resources.

Environmental Consistency

  • The packaged dependencies and configuration travel with the container wherever it goes. This along with version controlled Docker images leads to consistent environments.
  • No more “works on my machine” problems usually faced when shipping code.

Improved Developer Productivity

  • Docker streamlines your workflow with quick setup, reducing environment inconsistencies.
  • Use Docker CLI and APIs that provide programmatic access to Docker tools enabling automation through your CI/CD pipelines.
  • Save developers time and energy on configuration and focus more on innovation.

Simpler Maintenance

  • Containers share just the application layer and not the entire operating system. So there are less patches and updates to manage.
  • With Docker, you can easily roll back to previous versions of your application. Docker also makes troubleshooting problems simpler with options like debugging into containers.

Community and Ecosystem

  • Docker has a very large and active open source community with over 150K GitHub stars. It benefits from community contributions and an extensive ecosystem of tools.
  • Plenty of Docker plugins and complementary tools available like Kubernetes for container orchestration.

In summary, Docker makes it easier to create, deploy, scale, and manage containerized applications. By utilizing OS-level virtualization, it provides flexibility, portability and scalability to meet today’s dynamic application requirements.

Key Takeaways

  • Docker enables easier configuration and environment consistency across the app lifecycle.
  • It offers faster setup and greater productivity for developers.
  • Applications can be made modular using containers and easily ported across environments.
  • Containers provide improved scalability and resource efficiency over VMs.


Docker has evolved into an industry standard for containerizing and running distributed applications using containers. With its advantages like portability, resource efficiency and developer productivity, it has become the containerization tool of choice for companies big and small. As more organizations shift towards microservices and cloud native applications, Docker provides the ideal platform to build, share and manage these complex environments effectively.

Frequently Asked Questions

What is Docker used for?

Docker is used for developing, shipping, and running applications inside containers. Containers allow developers to package an app with all its dependencies into a standardized unit for software development.

Does Docker replace VMs?

Docker does not replace VMs but works at a different level of abstraction. Docker containers offer OS level virtualization while VMs provide hardware virtualization. Containers and VMs can be used together for added isolation.

How does Docker work?

Docker packages software into standardized units called containers that include everything the application needs to run such as libraries, tools, dependencies and configuration files. It then provides an easy way to deploy these containers as lightweight, portable encapsulations.

What are Docker containers?

Docker containers are lightweight, executable application components that run isolated processes on a shared host OS kernel. They can quickly start, execute and shut down. Each container encapsulates an application + dependencies as an individually deployable, standardized unit.

Is Docker safe?

Yes, Docker implements security features like access controls, network encryption, SSL/TLS certificate management and role based access to make the container infrastructure secure. Containers themselves are isolated from each other and the underlying host system.

Is Docker free?

Yes, Docker is free to use for development and testing. Docker Desktop for Windows and Mac is available at no cost. For commercial use in production, paid subscriptions of Docker Enterprise are available that include support and certifications.

What languages does Docker support?

Docker can package, deploy and run applications written in any language or framework. It can containerize applications built using Node, Python, Java, Go, Ruby, ASP.NET Core and more. The containers themselves are portable across systems.

What OS does Docker run on?

Docker runs on Windows, Linux and macOS. It utilizes the host system’s kernel thus works across Linux, Windows Server and modern Windows client OS releases. Docker Desktop allows developers to build and test containers easily on Windows and Mac machines.

What are some alternatives to Docker?

Some alternatives to Docker include rkt (by CoreOS), LXC (Linux containers), OpenVZ, Containerd and Cri-o. However, Docker leads the container market and has a much larger ecosystem of compatible tools and plugins.

How does Docker differ from VMs?

Docker provides operating system level virtualization using containerization techniques while VMs offer hardware virtualization by creating full virtual operating systems. Containers are thus much more lightweight, portable and efficient compared to VMs.

Is Kubernetes needed if I have Docker?

You can run Docker without orchestration but Kubernetes makes managing Docker clusters, networking, scaling and app deployments significantly easier. Kubernetes became essential as apps got decoupled into microservices across multi-cloud environments.

How do I create a Docker container?

You create Docker containers using the Docker image as the building source. An image includes all libraries, dependencies, tools and other elements. Simply use the docker build command to build an image, then docker create and docker run to generate containers from it.

How are containers different from VMs?

Containers offer OS level virtualization using shared kernel while VMs provide full hardware virtualization with separate kernels and OS. Hence containers have almost no overhead compared to VMs, making them much more lightweight and portable.

Do I need Docker if I use AWS?

Docker can simplify container management across cloud providers, offering standardized environments and portability across AWS EC2 instances, Lambda, on-prem and other infrastructure. So Docker still provides significant DevOps value on AWS.

What hosting providers support Docker?

All major cloud platforms like AWS, Azure, GCP and IBM Cloud support Docker containers. Docker Enterprise integrations are also available for AWS, Azure and IBM cloud to build and manage Docker environments on them.

How do containers compare to serverless platforms?

Containers package applications with their runtime environments while serverless platforms manage runtimes automatically. Both aim for abstraction and autoscaling. Containers have more predictable performance while serverless better handles spiky workloads.

Why containerization over hypervisor virtualization?

Containers provide OS level virtualization so are much more lightweight and efficient compared to hypervisors. They offer greater speed, scalability, density, portability, resource sharing and utilization across environments.

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