---
description: Get an in-depth overview of the Docker platform including what it can
  be used for, the architecture it employs, and its underlying technology.
keywords: what is a docker, docker daemon, why use docker, docker architecture, what
  to use docker for, docker client, what is docker for, why docker, uses for docker,
  what is docker container used for, what are docker containers used for
title: What is Docker?
weight: 20
aliases:
 - /introduction/understanding-docker/
 - /engine/userguide/basics/
 - /engine/introduction/understanding-docker/
 - /engine/understanding-docker/
 - /engine/docker-overview/
 - /get-started/overview/
 - /guides/docker-overview/
---

Docker is an open platform for developing, shipping, and running applications.
Docker enables you to separate your applications from your infrastructure so
you can deliver software quickly. With Docker, you can manage your infrastructure
in the same ways you manage your applications. By taking advantage of Docker's
methodologies for shipping, testing, and deploying code, you can
significantly reduce the delay between writing code and running it in production.

## The Docker platform

Docker provides the ability to package and run an application in a loosely isolated
environment called a container. The isolation and security lets you run many
containers simultaneously on a given host. Containers are lightweight and contain
everything needed to run the application, so you don't need to rely on what's
installed on the host. You can share containers while you work,
and be sure that everyone you share with gets the same container that works in the
same way.

Docker provides tooling and a platform to manage the lifecycle of your containers:

* Develop your application and its supporting components using containers.
* The container becomes the unit for distributing and testing your application.
* When you're ready, deploy your application into your production environment,
  as a container or an orchestrated service. This works the same whether your
  production environment is a local data center, a cloud provider, or a hybrid
  of the two.

## What can I use Docker for?

### Fast, consistent delivery of your applications

Docker streamlines the development lifecycle by allowing developers to work in
standardized environments using local containers which provide your applications
and services. Containers are great for continuous integration and continuous
delivery (CI/CD) workflows.

Consider the following example scenario:

- Your developers write code locally and share their work with their colleagues
  using Docker containers.
- They use Docker to push their applications into a test environment and run
  automated and manual tests.
- When developers find bugs, they can fix them in the development environment
  and redeploy them to the test environment for testing and validation.
- When testing is complete, getting the fix to the customer is as simple as
  pushing the updated image to the production environment.

### Responsive deployment and scaling

Docker's container-based platform allows for highly portable workloads. Docker
containers can run on a developer's local laptop, on physical or virtual
machines in a data center, on cloud providers, or in a mixture of environments.

Docker's portability and lightweight nature also make it easy to dynamically
manage workloads, scaling up or tearing down applications and services as
business needs dictate, in near real time.

### Running more workloads on the same hardware

Docker is lightweight and fast. It provides a viable, cost-effective alternative
to hypervisor-based virtual machines, so you can use more of your server
capacity to achieve your business goals. Docker is perfect for high density
environments and for small and medium deployments where you need to do more with
fewer resources.

## Docker architecture

Docker uses a client-server architecture. The Docker client talks to the
Docker daemon, which does the heavy lifting of building, running, and