|
...
|
...
|
@@ -9,40 +9,140 @@ FAQ
|
|
9
|
9
|
Most frequently asked questions.
|
|
10
|
10
|
--------------------------------
|
|
11
|
11
|
|
|
12
|
|
-1. **How much does Docker cost?**
|
|
|
12
|
+How much does Docker cost?
|
|
|
13
|
+..........................
|
|
13
|
14
|
|
|
14
|
15
|
Docker is 100% free, it is open source, so you can use it without paying.
|
|
15
|
16
|
|
|
16
|
|
-2. **What open source license are you using?**
|
|
17
|
|
-
|
|
18
|
|
- We are using the Apache License Version 2.0, see it here: https://github.com/dotcloud/docker/blob/master/LICENSE
|
|
19
|
|
-
|
|
20
|
|
-3. **Does Docker run on Mac OS X or Windows?**
|
|
21
|
|
-
|
|
22
|
|
- Not at this time, Docker currently only runs on Linux, but you can use VirtualBox to run Docker in a
|
|
23
|
|
- virtual machine on your box, and get the best of both worlds. Check out the :ref:`install_using_vagrant` and :ref:`windows` installation guides.
|
|
24
|
|
-
|
|
25
|
|
-4. **How do containers compare to virtual machines?**
|
|
26
|
|
-
|
|
27
|
|
- They are complementary. VMs are best used to allocate chunks of hardware resources. Containers operate at the process level, which makes them very lightweight and perfect as a unit of software delivery.
|
|
28
|
|
-
|
|
29
|
|
-5. **Can I help by adding some questions and answers?**
|
|
|
17
|
+What open source license are you using?
|
|
|
18
|
+.......................................
|
|
|
19
|
+
|
|
|
20
|
+ We are using the Apache License Version 2.0, see it here:
|
|
|
21
|
+ https://github.com/dotcloud/docker/blob/master/LICENSE
|
|
|
22
|
+
|
|
|
23
|
+Does Docker run on Mac OS X or Windows?
|
|
|
24
|
+.......................................
|
|
|
25
|
+
|
|
|
26
|
+ Not at this time, Docker currently only runs on Linux, but you can
|
|
|
27
|
+ use VirtualBox to run Docker in a virtual machine on your box, and
|
|
|
28
|
+ get the best of both worlds. Check out the
|
|
|
29
|
+ :ref:`install_using_vagrant` and :ref:`windows` installation
|
|
|
30
|
+ guides.
|
|
|
31
|
+
|
|
|
32
|
+How do containers compare to virtual machines?
|
|
|
33
|
+..............................................
|
|
|
34
|
+
|
|
|
35
|
+ They are complementary. VMs are best used to allocate chunks of
|
|
|
36
|
+ hardware resources. Containers operate at the process level, which
|
|
|
37
|
+ makes them very lightweight and perfect as a unit of software
|
|
|
38
|
+ delivery.
|
|
|
39
|
+
|
|
|
40
|
+What does Docker add to just plain LXC?
|
|
|
41
|
+.......................................
|
|
|
42
|
+
|
|
|
43
|
+ Docker is not a replacement for LXC. "LXC" refers to capabilities
|
|
|
44
|
+ of the Linux kernel (specifically namespaces and control groups)
|
|
|
45
|
+ which allow sandboxing processes from one another, and controlling
|
|
|
46
|
+ their resource allocations. On top of this low-level foundation of
|
|
|
47
|
+ kernel features, Docker offers a high-level tool with several
|
|
|
48
|
+ powerful functionalities:
|
|
|
49
|
+
|
|
|
50
|
+ * *Portable deployment across machines.*
|
|
|
51
|
+ Docker defines a format for bundling an application and all its
|
|
|
52
|
+ dependencies into a single object which can be transferred to
|
|
|
53
|
+ any Docker-enabled machine, and executed there with the
|
|
|
54
|
+ guarantee that the execution environment exposed to the
|
|
|
55
|
+ application will be the same. LXC implements process sandboxing,
|
|
|
56
|
+ which is an important pre-requisite for portable deployment, but
|
|
|
57
|
+ that alone is not enough for portable deployment. If you sent me
|
|
|
58
|
+ a copy of your application installed in a custom LXC
|
|
|
59
|
+ configuration, it would almost certainly not run on my machine
|
|
|
60
|
+ the way it does on yours, because it is tied to your machine's
|
|
|
61
|
+ specific configuration: networking, storage, logging, distro,
|
|
|
62
|
+ etc. Docker defines an abstraction for these machine-specific
|
|
|
63
|
+ settings, so that the exact same Docker container can run -
|
|
|
64
|
+ unchanged - on many different machines, with many different
|
|
|
65
|
+ configurations.
|
|
|
66
|
+
|
|
|
67
|
+ * *Application-centric.*
|
|
|
68
|
+ Docker is optimized for the deployment of applications, as
|
|
|
69
|
+ opposed to machines. This is reflected in its API, user
|
|
|
70
|
+ interface, design philosophy and documentation. By contrast, the
|
|
|
71
|
+ ``lxc`` helper scripts focus on containers as lightweight
|
|
|
72
|
+ machines - basically servers that boot faster and need less
|
|
|
73
|
+ RAM. We think there's more to containers than just that.
|
|
|
74
|
+
|
|
|
75
|
+ * *Automatic build.*
|
|
|
76
|
+ Docker includes :ref:`a tool for developers to automatically
|
|
|
77
|
+ assemble a container from their source code <dockerbuilder>`,
|
|
|
78
|
+ with full control over application dependencies, build tools,
|
|
|
79
|
+ packaging etc. They are free to use ``make, maven, chef, puppet,
|
|
|
80
|
+ salt,`` Debian packages, RPMs, source tarballs, or any
|
|
|
81
|
+ combination of the above, regardless of the configuration of the
|
|
|
82
|
+ machines.
|
|
|
83
|
+
|
|
|
84
|
+ * *Versioning.*
|
|
|
85
|
+ Docker includes git-like capabilities for tracking successive
|
|
|
86
|
+ versions of a container, inspecting the diff between versions,
|
|
|
87
|
+ committing new versions, rolling back etc. The history also
|
|
|
88
|
+ includes how a container was assembled and by whom, so you get
|
|
|
89
|
+ full traceability from the production server all the way back to
|
|
|
90
|
+ the upstream developer. Docker also implements incremental
|
|
|
91
|
+ uploads and downloads, similar to ``git pull``, so new versions
|
|
|
92
|
+ of a container can be transferred by only sending diffs.
|
|
|
93
|
+
|
|
|
94
|
+ * *Component re-use.*
|
|
|
95
|
+ Any container can be used as a :ref:`"base image"
|
|
|
96
|
+ <base_image_def>` to create more specialized components. This
|
|
|
97
|
+ can be done manually or as part of an automated build. For
|
|
|
98
|
+ example you can prepare the ideal Python environment, and use it
|
|
|
99
|
+ as a base for 10 different applications. Your ideal Postgresql
|
|
|
100
|
+ setup can be re-used for all your future projects. And so on.
|
|
|
101
|
+
|
|
|
102
|
+ * *Sharing.*
|
|
|
103
|
+ Docker has access to a `public registry
|
|
|
104
|
+ <http://index.docker.io>`_ where thousands of people have
|
|
|
105
|
+ uploaded useful containers: anything from Redis, CouchDB,
|
|
|
106
|
+ Postgres to IRC bouncers to Rails app servers to Hadoop to base
|
|
|
107
|
+ images for various Linux distros. The :ref:`registry
|
|
|
108
|
+ <registryindexspec>` also includes an official "standard
|
|
|
109
|
+ library" of useful containers maintained by the Docker team. The
|
|
|
110
|
+ registry itself is open-source, so anyone can deploy their own
|
|
|
111
|
+ registry to store and transfer private containers, for internal
|
|
|
112
|
+ server deployments for example.
|
|
|
113
|
+
|
|
|
114
|
+ * *Tool ecosystem.*
|
|
|
115
|
+ Docker defines an API for automating and customizing the
|
|
|
116
|
+ creation and deployment of containers. There are a huge number
|
|
|
117
|
+ of tools integrating with Docker to extend its
|
|
|
118
|
+ capabilities. PaaS-like deployment (Dokku, Deis, Flynn),
|
|
|
119
|
+ multi-node orchestration (Maestro, Salt, Mesos, Openstack Nova),
|
|
|
120
|
+ management dashboards (docker-ui, Openstack Horizon, Shipyard),
|
|
|
121
|
+ configuration management (Chef, Puppet), continuous integration
|
|
|
122
|
+ (Jenkins, Strider, Travis), etc. Docker is rapidly establishing
|
|
|
123
|
+ itself as the standard for container-based tooling.
|
|
|
124
|
+
|
|
|
125
|
+Can I help by adding some questions and answers?
|
|
|
126
|
+................................................
|
|
30
|
127
|
|
|
31
|
128
|
Definitely! You can fork `the repo`_ and edit the documentation sources.
|
|
32
|
129
|
|
|
33
|
130
|
|
|
34
|
|
-42. **Where can I find more answers?**
|
|
|
131
|
+Where can I find more answers?
|
|
|
132
|
+..............................
|
|
35
|
133
|
|
|
36
|
134
|
You can find more answers on:
|
|
37
|
135
|
|
|
38
|
|
- * `Docker club mailinglist`_
|
|
|
136
|
+ * `Docker user mailinglist`_
|
|
|
137
|
+ * `Docker developer mailinglist`_
|
|
39
|
138
|
* `IRC, docker on freenode`_
|
|
40
|
139
|
* `Github`_
|
|
41
|
140
|
* `Ask questions on Stackoverflow`_
|
|
42
|
141
|
* `Join the conversation on Twitter`_
|
|
43
|
142
|
|
|
44
|
143
|
|
|
45
|
|
- .. _Docker club mailinglist: https://groups.google.com/d/forum/docker-club
|
|
|
144
|
+ .. _Docker user mailinglist: https://groups.google.com/d/forum/docker-user
|
|
|
145
|
+ .. _Docker developer mailinglist: https://groups.google.com/d/forum/docker-dev
|
|
46
|
146
|
.. _the repo: http://www.github.com/dotcloud/docker
|
|
47
|
147
|
.. _IRC, docker on freenode: irc://chat.freenode.net#docker
|
|
48
|
148
|
.. _Github: http://www.github.com/dotcloud/docker
|
Andy Rothfusz authored on 2013/08/14 05:45:07