Docker - the open-source application container engine
Перейти к файлу
Michael Crosby 110b944f45 Merge pull request #2399 from dotcloud/fix_race_stdin_cli
Only pass stdin to hijack when needed
2013-10-25 17:32:36 -07:00
auth Hack: fix tests which didn't cleanup properly 2013-10-18 02:13:36 +00:00
contrib Merge pull request #2363 from tianon/mkimage-numeric-owner 2013-10-24 06:42:52 -07:00
docker remove useless os.Exit() after log.Fatalf 2013-10-24 00:25:55 -07:00
docs Typo in host integration docs 2013-10-23 10:19:12 -05:00
hack Merge pull request #2378 from tianon/linkify-github-ids 2013-10-25 11:30:25 -07:00
library Add GitHub usernames to MAINTAINERS 2013-08-09 21:16:44 -04:00
registry registry: fix content-type for PushImageJSONIndex 2013-10-22 11:56:48 -07:00
term discard errno = 0 errors 2013-10-16 23:05:50 +00:00
utils let utils.ParseHost return err when errors happen 2013-10-24 13:23:02 +08:00
vendor/src Bump vendor kr/pty to commit 3b1f6487b (syscall.O_NOCTTY) 2013-10-01 19:48:50 -06:00
.gitignore Add "vendor/pkg/" to .gitignore now that we "go test -i" 2013-10-18 12:18:13 -06:00
.mailmap Update AUTHORS 2013-10-08 23:51:38 -04:00
AUTHORS check return value of syscall.Chdir when changing working directory 2013-10-14 15:27:38 +08:00
CHANGELOG.md Update CHANGELOG.md 2013-10-17 11:26:17 -07:00
CONTRIBUTING.md Fix #1919 document how to edit and release docs. 2013-10-15 15:52:21 -07:00
Dockerfile Update Dockerfile test comment 2013-10-16 00:31:34 +00:00
FIXME Clean out a few outdated FIXME items 2013-10-06 13:55:26 -06:00
LICENSE Docker is now licensed under the Apache 2.0 license 2013-02-18 09:56:20 -08:00
MAINTAINERS Add GitHub usernames to MAINTAINERS 2013-08-09 21:16:44 -04:00
NOTICE Added more context. 2013-09-27 19:07:12 -07:00
README.md fix logo path 2013-09-30 16:54:04 -07:00
VERSION Merge branch 'release' 2013-10-16 18:20:04 -07:00
Vagrantfile Merge pull request #1813 from doubleyou/patch-1 2013-10-11 16:23:19 -07:00
api.go Fix issue killing container while sending signal 2013-10-18 16:19:27 -07:00
api_params.go use less reflection in command line method invocation 2013-09-23 01:06:31 +01:00
api_test.go swap cat by top to prevent 2 warnings 2013-10-24 15:06:10 -07:00
archive.go Fixed typos 2013-08-12 18:53:06 +01:00
archive_test.go Style fixes for fmt + err usage. 2013-07-04 14:33:17 -07:00
buildfile.go fix race condition in docker build with verbose + cleanup hostIntegration debug 2013-10-22 15:01:06 -07:00
buildfile_test.go Increase readbility of unit tests by using mkRuntime everywhere 2013-10-18 07:20:39 +00:00
changes.go Made calling changelog before run return empty. Fixes #1705. 2013-08-30 22:46:07 +02:00
commands.go only pass stdin to hijack when needed 2013-10-25 17:17:33 -07:00
commands_test.go fix workdir, hostname tests and a bunch on mount issue 2013-10-24 16:57:35 -07:00
container.go Merge pull request #2385 from dotcloud/suppress_even_more_warnings_test 2013-10-25 15:04:56 -07:00
container_test.go remove log 2013-10-24 15:13:47 -07:00
graph.go Merge pull request #1759 from bdon/graph-map 2013-09-10 08:49:11 -07:00
graph_test.go Replace Graph.All with Graph.Map 2013-08-31 20:44:42 -07:00
image.go Merge pull request #1267 from sridatta/new-clean-init 2013-08-05 13:23:22 -07:00
lxc_template.go Fixes issues with mounting subdirectories of /mnt in container. 2013-10-09 16:40:46 -04:00
mount.go Initial steps to fix Issue #936 2013-10-11 08:04:40 -05:00
mount_darwin.go Moved server and client logic into sub-packages docker/server and docker/client, respectively. The UI is not affected. 2013-02-13 17:10:00 -08:00
mount_linux.go go fmt 2013-02-26 17:26:46 -08:00
network.go Make sure to close the network allocators 2013-10-08 15:42:02 -07:00
network_proxy.go Catch errClosing error when TCP and UDP proxies are terminated. 2013-10-16 14:43:20 -07:00
network_proxy_test.go remove log 2013-10-24 15:13:47 -07:00
network_test.go Make sure the routes IP are taken into consideration + add unit test for network overlap detection 2013-08-01 18:12:39 -07:00
runtime.go Runtime: remove unused field kernelVersion 2013-10-23 00:44:57 -06:00
runtime_test.go remove log 2013-10-24 15:13:47 -07:00
server.go fix wrong untag while docker rmi 2013-10-21 17:03:32 -07:00
server_test.go Fix attach race condition, improve unit tests, make sure the container is started before unblocking Start 2013-10-18 16:26:16 -07:00
sorter.go Sort images by tag name when the creation date is the same. 2013-08-17 22:11:34 -07:00
sorter_test.go Sort images by tag name when the creation date is the same. 2013-08-17 22:11:34 -07:00
state.go Record termination time in state. 2013-10-10 14:47:25 -04:00
sysinit.go check return value of syscall.Chdir when changing working directory 2013-10-14 15:27:38 +08:00
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 add missing error check 2013-10-03 22:33:00 +00:00
utils_test.go hack: encode the name of the current test in temporary directories, for easier tracking 2013-10-18 07:29:07 +00:00
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

README.md

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.

Transfers of Docker shall be in accordance with applicable export controls of any country and all other applicable legal requirements. Docker shall not be distributed or downloaded to or in Cuba, Iran, North Korea, Sudan or Syria and shall not be distributed or downloaded to any person on the Denied Persons List administered by the U.S. Department of Commerce.