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121 lines
3.3 KiB
ReStructuredText
121 lines
3.3 KiB
ReStructuredText
==============
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Docker Builder
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==============
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.. contents:: Table of Contents
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1. Format
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=========
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The Docker builder format is quite simple:
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``instruction arguments``
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The first instruction must be `FROM`
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All instruction are to be placed in a file named `Dockerfile`
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In order to place comments within a Dockerfile, simply prefix the line with "`#`"
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2. Instructions
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===============
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Docker builder comes with a set of instructions:
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1. FROM: Set from what image to build
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2. RUN: Execute a command
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3. INSERT: Insert a remote file (http) into the image
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2.1 FROM
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--------
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``FROM <image>``
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The `FROM` instruction must be the first one in order for Builder to know from where to run commands.
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`FROM` can also be used in order to build multiple images within a single Dockerfile
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2.2 MAINTAINER
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--------------
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``MAINTAINER <name>``
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The `MAINTAINER` instruction allow you to set the Author field of the generated images.
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This instruction is never automatically reset.
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2.3 RUN
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-------
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``RUN <command>``
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The `RUN` instruction is the main one, it allows you to execute any commands on the `FROM` image and to save the results.
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You can use as many `RUN` as you want within a Dockerfile, the commands will be executed on the result of the previous command.
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2.4 CMD
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-------
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``CMD <command>``
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The `CMD` instruction sets the command to be executed when running the image.
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It is equivalent to do `docker commit -run '{"Cmd": <command>}'` outside the builder.
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.. note::
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Do not confuse `RUN` with `CMD`. `RUN` actually run a command and save the result, `CMD` does not execute anything.
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2.5 EXPOSE
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----------
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``EXPOSE <port> [<port>...]``
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The `EXPOSE` instruction sets ports to be publicly exposed when running the image.
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This is equivalent to do `docker commit -run '{"PortSpecs": ["<port>", "<port2>"]}'` outside the builder.
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2.6 INSERT
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----------
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``INSERT <file url> <path>``
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The `INSERT` instruction will download the file at the given url and place it within the image at the given path.
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.. note::
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The path must include the file name.
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3. Dockerfile Examples
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======================
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::
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# Nginx
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#
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# VERSION 0.0.1
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# DOCKER-VERSION 0.2
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from ubuntu
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maintainer Guillaume J. Charmes "guillaume@dotcloud.com"
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# make sure the package repository is up to date
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run echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list
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run apt-get update
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run apt-get install -y inotify-tools nginx apache openssh-server
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insert https://raw.github.com/creack/docker-vps/master/nginx-wrapper.sh /usr/sbin/nginx-wrapper
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::
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# Firefox over VNC
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#
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# VERSION 0.3
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# DOCKER-VERSION 0.2
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from ubuntu
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# make sure the package repository is up to date
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run echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list
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run apt-get update
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# Install vnc, xvfb in order to create a 'fake' display and firefox
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run apt-get install -y x11vnc xvfb firefox
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run mkdir /.vnc
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# Setup a password
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run x11vnc -storepasswd 1234 ~/.vnc/passwd
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# Autostart firefox (might not be the best way to do it, but it does the trick)
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run bash -c 'echo "firefox" >> /.bashrc'
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expose 5900
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cmd ["x11vnc", "-forever", "-usepw", "-create"]
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