Docker - the open-source application container engine
Go Shell PowerShell Makefile C Vim script
Latest commit dc1f036 Mar 27, 2017 @vdemeester vdemeester committed on GitHub Merge pull request #32119 from nogoegst/fix-openbsd-cli
Fix building client on OpenBSD
Failed to load latest commit information.
.github Update Oct 17, 2016
api Add `--filter scope=swarm|local` for `docker network ls` Mar 24, 2017
builder Merge pull request #31257 from tonistiigi/nested-build Mar 24, 2017
cli Merge pull request #31976 from Microsoft/jjh/csbooboo Mar 26, 2017
client Merge pull request #31710 from sanimej/drillerrr Mar 14, 2017
cmd Merge pull request #31668 from Microsoft/jjh/nopidfileasservice Mar 23, 2017
container Add missing resources to update block for Windows containers Mar 8, 2017
contrib Merge pull request #31976 from Microsoft/jjh/csbooboo Mar 26, 2017
daemon Merge pull request #31755 from miaoyq/heartbeat-maybe-zero Mar 27, 2017
distribution Merge pull request #31720 from jonjohnsonjr/always-head Mar 16, 2017
dockerversion Move UAStringKey to dockerversion pkg Dec 27, 2016
docs Merge pull request #32075 from uhayate/update_old_docs Mar 26, 2017
experimental Update Mar 8, 2017
hack Merge pull request #30514 from FrenchBen/yaml Mar 15, 2017
hooks docs: added support for CLI yaml file generation Mar 14, 2017
image Wrap errors in digest package so they are consistent between platforms. Mar 8, 2017
integration-cli remove redundant comments in test build.go Mar 27, 2017
keys Do not use keyservers to fetch GPG keys for apt Jan 7, 2017
layer modify ID to ChainID to avoid confusing Mar 9, 2017
libcontainerd Merge pull request #31629 from darrenstahlmsft/ShutdownLock Mar 24, 2017
man Add `--filter scope=swarm|local` for `docker network ls` Mar 24, 2017
migrate/v1 Use distribution reference Feb 7, 2017
oci oci/namespace: remove unnecessary variable idx Dec 22, 2016
opts api: Remove SecretRequestOption type Mar 16, 2017
pkg Fix building client on OpenBSD Mar 26, 2017
plugin Merge pull request #32095 from anusha-ragunathan/set-state Mar 24, 2017
profiles profiles: seccomp: allow clock_settime when CAP_SYS_TIME is added Mar 20, 2017
project Rename project/ -> project/ Mar 15, 2017
reference reference: handle combination of tag and digest in ImageDelete Feb 16, 2017
registry Validate insecure registry (`--insecure-registry`) values Feb 14, 2017
restartmanager Adding support for docker max restart time Feb 4, 2017
runconfig fixed:go vetting warning unkeyed fields Mar 20, 2017
vendor Revendor HCSShim @ v0.5.13 Mar 23, 2017
volume Add non-nil check before logging volume errors. Mar 24, 2017
.dockerignore [EXPERIMENTAL] Integration Test on Swarm Feb 28, 2017
.gitignore [EXPERIMENTAL] Integration Test on Swarm Feb 28, 2017
.mailmap Update authors Feb 23, 2017
AUTHORS Update authors Feb 23, 2017 Fix typo in Mar 8, 2017 CONTRIBUTING: add tips for succesful changes Jan 17, 2017
Dockerfile Dockerfile: move comments to fix build error Mar 16, 2017
Dockerfile.aarch64 Dockerfile: move comments to fix build error Mar 16, 2017
Dockerfile.armhf Seccomp Update Mar 7, 2017
Dockerfile.ppc64le [ppc64le] fix notary vendor link Mar 22, 2017
Dockerfile.s390x Seccomp Update Mar 7, 2017
Dockerfile.simple Seccomp Update Mar 7, 2017
Dockerfile.solaris Add functional support for Docker sub commands on Solaris Nov 7, 2016 update git, hoist powershell setttings to top and use simpler way to … Feb 13, 2017
LICENSE Update copyright dates Feb 24, 2017
MAINTAINERS Move Jana to alumni Mar 6, 2017
Makefile docs: added support for CLI yaml file generation Mar 14, 2017
NOTICE Update LICENSE date Feb 15, 2017 Remove old documentation, add with pointer Oct 12, 2016 Header has incorrect punctuation. Dec 19, 2016 fix the bare url and the Summary of Jan 17, 2017
VERSION prepare master for the next release Mar 15, 2017
poule.yml update poule-config; add Yong to auto-assignment Mar 2, 2017
vendor.conf Revendor HCSShim @ v0.5.13 Mar 23, 2017

Docker: the container engine Release

Docker is an open source project to pack, ship and run any application as a lightweight container.

Docker containers are both hardware-agnostic and platform-agnostic. This means they can run anywhere, from your laptop to the largest cloud compute instance and everything in between - and they don't require you to use a particular language, framework or packaging system. That makes them great building blocks for deploying and scaling web apps, databases, and backend services without depending on a particular stack or provider.

Docker began as an open-source implementation of the deployment engine which powered dotCloud, a popular Platform-as-a-Service. It benefits directly from the experience accumulated over several years of large-scale operation and support of hundreds of thousands of applications and databases.

Docker logo

Security Disclosure

Security is very important to us. If you have any issue regarding security, please disclose the information responsibly by sending an email to and not by creating a GitHub issue.

Better than VMs

A common method for distributing applications and sandboxing their execution is to use virtual machines, or VMs. Typical VM formats are VMware's vmdk, Oracle VirtualBox's vdi, and Amazon EC2's ami. In theory these formats should allow every developer to automatically package their application into a "machine" for easy distribution and deployment. In practice, that almost never happens, for a few reasons:

  • Size: VMs are very large which makes them impractical to store and transfer.
  • Performance: running VMs consumes significant CPU and memory, which makes them impractical in many scenarios, for example local development of multi-tier applications, and large-scale deployment of cpu and memory-intensive applications on large numbers of machines.
  • Portability: competing VM environments don't play well with each other. Although conversion tools do exist, they are limited and add even more overhead.
  • Hardware-centric: VMs were designed with machine operators in mind, not software developers. As a result, they offer very limited tooling for what developers need most: building, testing and running their software. For example, VMs offer no facilities for application versioning, monitoring, configuration, logging or service discovery.

By contrast, Docker relies on a different sandboxing method known as containerization. Unlike traditional virtualization, containerization takes place at the kernel level. Most modern operating system kernels now support the primitives necessary for containerization, including Linux with openvz, vserver and more recently lxc, Solaris with zones, and FreeBSD with Jails.

Docker builds on top of these low-level primitives to offer developers a portable format and runtime environment that solves all four problems. Docker containers are small (and their transfer can be optimized with layers), they have basically zero memory and cpu overhead, they are completely portable, and are designed from the ground up with an application-centric design.

Perhaps best of all, because Docker operates at the OS level, it can still be run inside a VM!

Plays well with others

Docker does not require you to buy into a particular programming language, framework, packaging system, or configuration language.

Is your application a Unix process? Does it use files, tcp connections, environment variables, standard Unix streams and command-line arguments as inputs and outputs? Then Docker can run it.

Can your application's build be expressed as a sequence of such commands? Then Docker can build it.

Escape dependency hell

A common problem for developers is the difficulty of managing all their application's dependencies in a simple and automated way.

This is usually difficult for several reasons:

  • Cross-platform dependencies. Modern applications often depend on a combination of system libraries and binaries, language-specific packages, framework-specific modules, internal components developed for another project, etc. These dependencies live in different "worlds" and require different tools - these tools typically don't work well with each other, requiring awkward custom integrations.

  • Conflicting dependencies. Different applications may depend on different versions of the same dependency. Packaging tools handle these situations with various degrees of ease - but they all handle them in different and incompatible ways, which again forces the developer to do extra work.

  • Custom dependencies. A developer may need to prepare a custom version of their application's dependency. Some packaging systems can handle custom versions of a dependency, others can't - and all of them handle it differently.

Docker solves the problem of dependency hell by giving the developer a simple way to express all their application's dependencies in one place, while streamlining the process of assembling them. If this makes you think of XKCD 927, don't worry. Docker doesn't replace your favorite packaging systems. It simply orchestrates their use in a simple and repeatable way. How does it do that? With layers.

Docker defines a build as running a sequence of Unix commands, one after the other, in the same container. Build commands modify the contents of the container (usually by installing new files on the filesystem), the next command modifies it some more, etc. Since each build command inherits the result of the previous commands, the order in which the commands are executed expresses dependencies.

Here's a typical Docker build process:

FROM ubuntu:12.04
RUN apt-get update && apt-get install -y python python-pip curl
RUN curl -sSL | tar -xzv
RUN cd helloflask-master && pip install -r requirements.txt

Note that Docker doesn't care how dependencies are built - as long as they can be built by running a Unix command in a container.

Getting started

Docker can be installed either on your computer for building applications or on servers for running them. To get started, check out the installation instructions in the documentation.

Usage examples

Docker can be used to run short-lived commands, long-running daemons (app servers, databases, etc.), interactive shell sessions, etc.

You can find a list of real-world examples in the documentation.

Under the hood

Under the hood, Docker is built on the following components:

Contributing to Docker GoDoc

Master (Linux) Experimental (Linux) Windows FreeBSD
Jenkins Build Status Jenkins Build Status Build Status Build Status

Want to hack on Docker? Awesome! We have instructions to help you get started contributing code or documentation.

These instructions are probably not perfect, please let us know if anything feels wrong or incomplete. Better yet, submit a PR and improve them yourself.

Getting the development builds

Want to run Docker from a master build? You can download master builds at They are updated with each commit merged into the master branch.

Don't know how to use that super cool new feature in the master build? Check out the master docs at

How the project is run

Docker is a very, very active project. If you want to learn more about how it is run, or want to get more involved, the best place to start is the project directory.

We are always open to suggestions on process improvements, and are always looking for more maintainers.

Talking to other Docker users and contributors

Internet Relay Chat (IRC)

IRC is a direct line to our most knowledgeable Docker users; we have both the #docker and #docker-dev group on IRC is a rich chat protocol but it can overwhelm new users. You can search our chat archives.

Read our IRC quickstart guide for an easy way to get started.
Docker Community Forums The Docker Engine group is for users of the Docker Engine project.
Google Groups The docker-dev group is for contributors and other people contributing to the Docker project. You can join this group without a Google account by sending an email to You'll receive a join-request message; simply reply to the message to confirm your subscription.
Twitter You can follow Docker's Twitter feed to get updates on our products. You can also tweet us questions or just share blogs or stories.
Stack Overflow Stack Overflow has over 7000 Docker questions listed. We regularly monitor Docker questions and so do many other knowledgeable Docker users.


Brought to you courtesy of our legal counsel. For more context, please see the NOTICE document in this repo.

Use and transfer of Docker may be subject to certain restrictions by the United States and other governments.

It is your responsibility to ensure that your use and/or transfer does not violate applicable laws.

For more information, please see


Docker is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.

Other Docker Related Projects

There are a number of projects under development that are based on Docker's core technology. These projects expand the tooling built around the Docker platform to broaden its application and utility.

  • Docker Registry: Registry server for Docker (hosting/delivery of repositories and images)
  • Docker Machine: Machine management for a container-centric world
  • Docker Swarm: A Docker-native clustering system
  • Docker Compose (formerly Fig): Define and run multi-container apps
  • Kitematic: The easiest way to use Docker on Mac and Windows

If you know of another project underway that should be listed here, please help us keep this list up-to-date by submitting a PR.


You can find more projects, tools and articles related to Docker on the awesome-docker list. Add your project there.