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Moby Project - a collaborative project for the container ecosystem to assemble container-based systems
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Victor Vieux 5a4113140e Merge pull request #43 from alexlarsson/dm-plugin-use-root-subdir
devmapper: Use a "root" subdirectory in the devmapper volume
2013-11-19 13:51:04 -08:00
archive Implement fallback for getting the size of a container 2013-11-19 10:36:54 +01:00
auth Hack: fix tests which didn't cleanup properly 2013-10-18 02:13:36 +00:00
contrib Merge pull request #2652 from tianon/upstart-defaults-too 2013-11-13 10:42:41 -08:00
docker Merge branch 'job-create-start-clean' into engine-patch-2 2013-11-13 00:36:20 +00:00
dockerinit Rename all cases of "docker-init" to "dockerinit" for consistency 2013-10-25 15:13:25 -07:00
docs thankyou @tomdz - I forgot about URL based ADDs 2013-11-14 14:53:55 +10:00
engine gofmt 2013-11-13 19:25:55 +00:00
graphdb rename gograph in graphdb 2013-11-15 15:55:45 -08:00
graphdriver Merge pull request #43 from alexlarsson/dm-plugin-use-root-subdir 2013-11-19 13:51:04 -08:00
hack Typo in ROADMAP.md 2013-11-13 12:32:49 +00:00
iptables Correctly express "any address" to iptables. 2013-11-09 19:40:56 -08:00
namesgenerator go fmt 2013-11-07 12:27:33 -08:00
netlink go fmt 2013-11-07 12:27:33 -08:00
proxy Add links for container relationships and introspection 2013-10-25 15:13:24 -07:00
registry update docker search to reflect future changes of the api 2013-10-31 19:14:11 -07:00
sysinit Fixed problem with variables containing \n. 2013-10-31 01:19:32 +01:00
term discard errno = 0 errors 2013-10-16 23:05:50 +00:00
utils Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
vendor/src Add links for container relationships and introspection 2013-10-25 15:13:24 -07:00
.gitignore docker-ci 0.4.5: Sync tests with progress in docker and docker-registry. Use revamped shiny DinD. 2013-11-06 20:05:26 -08:00
.mailmap Update AUTHORS 2013-10-08 23:51:38 -04:00
api.go Fix the brittle errorstring-to-httperror recognition code which in turn is required by autopull (the client issues a pull if container creation returns 404) 2013-11-14 23:54:28 +00:00
api_params.go Print devicemapper status details in docker info 2013-11-15 11:04:02 +01:00
api_test.go Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
AUTHORS Merge pull request #2527 from jpoimboe/fedora-iptables-fix 2013-11-11 15:12:40 -08:00
buildfile.go Allow drivers to implement ApplyDiff in Differ interface 2013-11-11 19:09:57 -08:00
buildfile_test.go Merge branch 'job-create-start-clean' into engine-patch-2 2013-11-13 00:36:20 +00:00
CHANGELOG.md Removes duplicate changelog entry 2013-11-08 17:17:39 -05:00
commands.go Print devicemapper status details in docker info 2013-11-15 11:04:02 +01:00
commands_test.go Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
config.go Merge branch 'job-create-start-clean' into engine-patch-2 2013-11-13 00:36:20 +00:00
container.go Implement fallback for getting the size of a container 2013-11-19 10:36:54 +01:00
container_test.go Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
CONTRIBUTING.md CONTRIBUTING: wrap a couple of long lines 2013-11-11 16:21:34 +05:30
Dockerfile Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
FIXME Clean out a few outdated FIXME items 2013-10-06 13:55:26 -06:00
graph.go Unlink docker init files 2013-11-14 21:23:23 -08:00
graph_test.go Don't hardcode dependency on aufs in the tests 2013-11-08 02:49:08 +00:00
image.go Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
LICENSE Docker is now licensed under the Apache 2.0 license 2013-02-18 09:56:20 -08:00
links.go Check the output of iptables command. 2013-11-05 08:33:13 -08:00
links_test.go Expose IP, port, proto as sep. env vars when linking, Closes #2430 2013-10-28 23:02:28 -07:00
lxc_template.go Refactor HostConfig and escape apparmor confinement 2013-11-01 13:55:19 -07:00
MAINTAINERS Add GitHub usernames to MAINTAINERS 2013-08-09 21:16:44 -04:00
network.go network: add iptables rules to explicitly allow forwarding 2013-11-07 16:23:39 -06:00
network_test.go Prevent DNS server conflicts in CreateBridgeIface 2013-11-05 21:24:37 -06:00
NOTICE Change crypto export notice to meet Debian requirements 2013-11-11 22:08:37 +00:00
README.md Change crypto export notice to meet Debian requirements 2013-11-11 22:08:37 +00:00
runtime.go Add container migration to aufs driver 2013-11-18 18:39:21 -08:00
runtime_test.go Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
server.go rename gograph in graphdb 2013-11-15 15:55:45 -08:00
server_test.go gofmt 2013-11-13 19:25:55 +00:00
sorter.go rework images JSON 2013-11-06 03:58:15 +00:00
sorter_test.go make existing tests pass 2013-11-06 03:58:16 +00:00
state.go fix merge issue and gofmt 2013-10-25 15:13:25 -07:00
tags.go Reverse priority of tag lookup in TagStore.GetImage 2013-07-12 23:56:36 +01:00
tags_test.go Simplify unit tests code with mkRuntime() 2013-07-11 17:59:25 -07:00
utils.go Merge branch 'master' into shykes-0.6.5-dm-plugin 2013-11-14 14:02:44 -08:00
utils_test.go gofmt 2013-11-13 19:25:55 +00:00
Vagrantfile Vagrantfile updates. 2013-11-10 23:39:26 -08:00
VERSION Merge pull request #2577 from dotcloud/bump_v0.6.6 2013-11-06 13:41:52 -08:00
z_final_test.go Hack: don't run integration tests in /var/lib/docker/unit-tests; add missing cleanups in a few tests 2013-10-18 02:13:36 +00:00

Docker: the Linux container engine

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 that they can run anywhere, from your laptop to the largest EC2 compute instance and everything in between - and they don't require that you 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 is an open-source implementation of the deployment engine which powers 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 L

Better than VMs

A common method for distributing applications and sandbox 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 4 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.

The best part: because docker operates at the OS level, it can still be run inside a VM!

Plays well with others

Docker does not require that you 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 dependency hell by giving the developer a simple way to express all their application's dependencies in one place, and streamline 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:12.10
run apt-get update
run DEBIAN_FRONTEND=noninteractive apt-get install -q -y python
run DEBIAN_FRONTEND=noninteractive apt-get install -q -y python-pip
run pip install django
run DEBIAN_FRONTEND=noninteractive apt-get install -q -y curl
run curl -L https://github.com/shykes/helloflask/archive/master.tar.gz | 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 on your local machine as well as servers - both bare metal and virtualized. It is available as a binary on most modern Linux systems, or as a VM on Windows, Mac and other systems.

We also offer an interactive tutorial for quickly learning the basics of using Docker.

For up-to-date install instructions and online tutorials, see the Getting Started page.

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:

  • The cgroup and namespacing capabilities of the Linux kernel;
  • AUFS, a powerful union filesystem with copy-on-write capabilities;
  • The Go programming language;
  • lxc, a set of convenience scripts to simplify the creation of Linux containers.

Contributing to Docker

Want to hack on Docker? Awesome! There are instructions to get you started here.

They are probably not perfect, please let us know if anything feels wrong or incomplete.

Brought to you courtesy of our legal counsel. For more context, please see the Notice document.

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 http://www.bis.doc.gov