Dockerfile文件详细教程

写在前面

Dockerfile是用来构建镜像的，他实际上就是把在linux下的命令操作写到了Dockerfile中，通过Dockerfile去执行设置好的操作命令，保证通过Dockerfile的构建镜像是一致的。

实战分析

该例子来自于 chromium 项目
主要干的事情：

1. 来指定用哪个镜像；
2. 安装一些编译需要的环境：C++编译环境，Java环境等

# This Dockerfile specifies the recipe for creating an image for the tests
# to run in.
#
# We install as many test dependencies here as we can, because these setup
# steps can be cached.  They do *not* run every time we run the build.
# The Docker image is only rebuilt when the Dockerfile (ie. this file)
# changes.# 指定了使用什么镜像 debian
# Base Dockerfile for gRPC dev images
FROM debian:latest# 添加软件源
# Apt source for old Python versions.
RUN echo 'deb http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu trusty main' > /etc/apt/sources.list.d/deadsnakes.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys DB82666C# Apt source for Oracle Java.
RUN echo 'deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main' > /etc/apt/sources.list.d/webupd8team-java-trusty.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EEA14886 && \echo "oracle-java7-installer shared/accepted-oracle-license-v1-1 select true" | debconf-set-selections# Apt source for Mono
RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" | tee /etc/apt/sources.list.d/mono-xamarin.list && \echo "deb http://download.mono-project.com/repo/debian wheezy-libjpeg62-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF# Apt source for php
RUN echo "deb http://ppa.launchpad.net/ondrej/php/ubuntu trusty main" | tee /etc/apt/sources.list.d/various-php.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F4FCBB07# Install dotnet SDK based on https://www.microsoft.com/net/core#debian
# (Ubuntu instructions need apt to support https)
RUN apt-get update && apt-get install -y --force-yes curl libunwind8 gettext && \curl -sSL -o dotnet.tar.gz https://go.microsoft.com/fwlink/?LinkID=847105 &&  \mkdir -p /opt/dotnet && tar zxf dotnet.tar.gz -C /opt/dotnet && \ln -s /opt/dotnet/dotnet /usr/local/bin# Install dependencies.  We start with the basic ones require to build protoc
# and the C++ build
RUN apt-get clean && apt-get update && apt-get install -y --force-yes \autoconf \autotools-dev \build-essential \bzip2 \ccache \curl \gcc \git \libc6 \libc6-dbg \libc6-dev \libgtest-dev \libtool \make \parallel \time \wget \# -- For csharp --mono-devel \referenceassemblies-pcl \nunit \# -- For all Java builds -- \maven \# -- For java_jdk6 -- \#   oops! not in jessie. too old? openjdk-6-jdk \# -- For java_jdk7 -- \openjdk-7-jdk \# -- For java_oracle7 -- \oracle-java7-installer \# -- For python / python_cpp -- \python-setuptools \python-pip \python-dev \python2.6-dev \python3.3-dev \python3.4-dev \# -- For Ruby --ruby \# -- For C++ benchmarks --cmake \# -- For PHP --php5.6     \php5.6-dev \php5.6-xml \php7.0     \php7.0-dev \php7.0-xml \phpunit    \valgrind   \libxml2-dev \&& apt-get clean##################
# C# dependenciesRUN wget www.nuget.org/NuGet.exe -O /usr/local/bin/nuget.exe##################
# Python dependencies# These packages exist in apt-get, but their versions are too old, so we have
# to get updates from pip.RUN pip install pip --upgrade
RUN pip install virtualenv tox yattag##################
# Ruby dependencies# Install rvm
RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
RUN \curl -sSL https://get.rvm.io | bash -s stable# Install Ruby 2.1, Ruby 2.2 and JRuby 1.7
RUN /bin/bash -l -c "rvm install ruby-2.1"
RUN /bin/bash -l -c "rvm install ruby-2.2"
RUN /bin/bash -l -c "rvm install jruby-1.7"
RUN /bin/bash -l -c "echo 'gem: --no-ri --no-rdoc' > ~/.gemrc"
RUN /bin/bash -l -c "echo 'export PATH=/usr/local/rvm/bin:$PATH' >> ~/.bashrc"
RUN /bin/bash -l -c "gem install bundler --no-ri --no-rdoc"##################
# Java dependencies# This step requires compiling protoc. :(ENV MAVEN_REPO /var/maven_local_repository
ENV MVN mvn --batch-modeRUN cd /tmp && \git clone https://github.com/google/protobuf.git && \cd protobuf && \git reset --hard 129a6e2aca95dcfb6c3e717d7b9cca1f104fde39 && \./autogen.sh && \./configure && \make -j4 && \cd java && \$MVN install dependency:go-offline -Dmaven.repo.local=$MAVEN_REPO && \cd ../javanano && \$MVN install dependency:go-offline -Dmaven.repo.local=$MAVEN_REPO##################
# PHP dependencies.
RUN wget http://am1.php.net/get/php-5.5.38.tar.bz2/from/this/mirror
RUN mv mirror php-5.5.38.tar.bz2
RUN tar -xvf php-5.5.38.tar.bz2
RUN cd php-5.5.38 && ./configure --enable-maintainer-zts --prefix=/usr/local/php-5.5-zts && \make && make install && cd ..
RUN cd php-5.5.38 && make clean && ./configure --enable-bcmath --prefix=/usr/local/php-5.5 && \make && make install && cd ..RUN wget http://am1.php.net/get/php-5.6.30.tar.bz2/from/this/mirror
RUN mv mirror php-5.6.30.tar.bz2
RUN tar -xvf php-5.6.30.tar.bz2
RUN cd php-5.6.30 && ./configure --enable-maintainer-zts --prefix=/usr/local/php-5.6-zts && \make && make install && cd ..
RUN cd php-5.6.30 && make clean && ./configure --enable-bcmath --prefix=/usr/local/php-5.6 && \make && make install && cd ..RUN wget http://am1.php.net/get/php-7.0.18.tar.bz2/from/this/mirror
RUN mv mirror php-7.0.18.tar.bz2
RUN tar -xvf php-7.0.18.tar.bz2
RUN cd php-7.0.18 && ./configure --enable-maintainer-zts --prefix=/usr/local/php-7.0-zts && \make && make install && cd ..
RUN cd php-7.0.18 && make clean && ./configure --enable-bcmath --prefix=/usr/local/php-7.0 && \make && make install && cd ..RUN wget http://am1.php.net/get/php-7.1.4.tar.bz2/from/this/mirror
RUN mv mirror php-7.1.4.tar.bz2
RUN tar -xvf php-7.1.4.tar.bz2
RUN cd php-7.1.4 && ./configure --enable-maintainer-zts --prefix=/usr/local/php-7.1-zts && \make && make install && cd ..
RUN cd php-7.1.4 && make clean && ./configure --enable-bcmath --prefix=/usr/local/php-7.1 && \make && make install && cd ..RUN php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
RUN php composer-setup.php
RUN mv composer.phar /usr/bin/composer
RUN php -r "unlink('composer-setup.php');"
RUN composer config -g -- disable-tls true
RUN composer config -g -- secure-http false
RUN cd /tmp && \rm -rf protobuf && \git clone https://github.com/google/protobuf.git && \cd protobuf && \git reset --hard 49b44bff2b6257a119f9c6a342d6151c736586b8 && \cd php && \ln -sfn /usr/local/php-5.5/bin/php /usr/bin/php && \ln -sfn /usr/local/php-5.5/bin/php-config /usr/bin/php-config && \ln -sfn /usr/local/php-5.5/bin/phpize /usr/bin/phpize && \composer install && \mv vendor /usr/local/vendor-5.5 && \ln -sfn /usr/local/php-5.6/bin/php /usr/bin/php && \ln -sfn /usr/local/php-5.6/bin/php-config /usr/bin/php-config && \ln -sfn /usr/local/php-5.6/bin/phpize /usr/bin/phpize && \composer install && \mv vendor /usr/local/vendor-5.6 && \ln -sfn /usr/local/php-7.0/bin/php /usr/bin/php && \ln -sfn /usr/local/php-7.0/bin/php-config /usr/bin/php-config && \ln -sfn /usr/local/php-7.0/bin/phpize /usr/bin/phpize && \composer install && \mv vendor /usr/local/vendor-7.0 && \ln -sfn /usr/local/php-7.1/bin/php /usr/bin/php && \ln -sfn /usr/local/php-7.1/bin/php-config /usr/bin/php-config && \ln -sfn /usr/local/php-7.1/bin/phpize /usr/bin/phpize && \composer install && \mv vendor /usr/local/vendor-7.1##################
# Go dependencies.
RUN apt-get install -y  \# -- For go -- \golang##################
# Javascript dependencies.
RUN apt-get install -y \# -- For javascript -- \npm##################
# Python 3.5 3.6 dependencies.
RUN apt-get clean && apt-get update && apt-get install -y --force-yes \python3.5-dev \python3.6-dev \&& apt-get clean# On Debian/Ubuntu, nodejs binary is named 'nodejs' because the name 'node'
# is taken by another legacy binary. We don't have that legacy binary and
# npm expects the binary to be named 'node', so we just create a symbol
# link here.
RUN ln -s `which nodejs` /usr/bin/node##################
# Prepare ccacheRUN ln -s /usr/bin/ccache /usr/local/bin/gcc
RUN ln -s /usr/bin/ccache /usr/local/bin/g++
RUN ln -s /usr/bin/ccache /usr/local/bin/cc
RUN ln -s /usr/bin/ccache /usr/local/bin/c++
RUN ln -s /usr/bin/ccache /usr/local/bin/clang
RUN ln -s /usr/bin/ccache /usr/local/bin/clang++# Define the default command.
CMD ["bash"]

常见命令解释

FROM 指定镜像源

FROM ubuntu

# Base Dockerfile for gRPC dev images
FROM debian:latest

网站：http://hub.docker.com
FROM命令是用来指定你需要用哪个镜像作为基础镜像进行构建，一般来说Dockerfile的第一行都会先指定一个镜像，官方仓库中有很多镜像，可以通过http://hub.docker.com进行搜索，建议尽量使用官方镜像作为基础镜像，因为官方镜像都是精简过的稳定版。

RUN 执行linux命令

比如我们需要安装vim
写法1：

RUN apt-get update -y
RUN apt-get install -y vim

RUN是用来执行linux命令的指令，例如ubuntu系统下，需要更新软件包list，就需要执行apt-get update，之后会跟着执行apt-get install
写法2：

RUN apt-get update -y \&& apt-get install -y vim

参考例子：

# Apt source for old Python versions.
RUN echo 'deb http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu trusty main' > /etc/apt/sources.list.d/deadsnakes.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys DB82666C# Apt source for Oracle Java.
RUN echo 'deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main' > /etc/apt/sources.list.d/webupd8team-java-trusty.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EEA14886 && \echo "oracle-java7-installer shared/accepted-oracle-license-v1-1 select true" | debconf-set-selections# Apt source for Mono
RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" | tee /etc/apt/sources.list.d/mono-xamarin.list && \echo "deb http://download.mono-project.com/repo/debian wheezy-libjpeg62-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF# Apt source for php
RUN echo "deb http://ppa.launchpad.net/ondrej/php/ubuntu trusty main" | tee /etc/apt/sources.list.d/various-php.list && \apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F4FCBB07# Install dotnet SDK based on https://www.microsoft.com/net/core#debian
# (Ubuntu instructions need apt to support https)
RUN apt-get update && apt-get install -y --force-yes curl libunwind8 gettext && \curl -sSL -o dotnet.tar.gz https://go.microsoft.com/fwlink/?LinkID=847105 &&  \mkdir -p /opt/dotnet && tar zxf dotnet.tar.gz -C /opt/dotnet && \ln -s /opt/dotnet/dotnet /usr/local/bin# Install dependencies.  We start with the basic ones require to build protoc
# and the C++ build
RUN apt-get clean && apt-get update && apt-get install -y --force-yes \autoconf \autotools-dev \build-essential \bzip2 \ccache \curl \gcc \git \libc6 \libc6-dbg \libc6-dev \libgtest-dev \libtool \make \parallel \time \wget \# -- For csharp --mono-devel \referenceassemblies-pcl \nunit \# -- For all Java builds -- \maven \# -- For java_jdk6 -- \#   oops! not in jessie. too old? openjdk-6-jdk \# -- For java_jdk7 -- \openjdk-7-jdk \# -- For java_oracle7 -- \oracle-java7-installer \# -- For python / python_cpp -- \python-setuptools \python-pip \python-dev \python2.6-dev \python3.3-dev \python3.4-dev \# -- For Ruby --ruby \# -- For C++ benchmarks --cmake \# -- For PHP --php5.6     \php5.6-dev \php5.6-xml \php7.0     \php7.0-dev \php7.0-xml \phpunit    \valgrind   \libxml2-dev \&& apt-get clean##################
# C# dependenciesRUN wget www.nuget.org/NuGet.exe -O /usr/local/bin/nuget.exe##################
# Python dependencies# These packages exist in apt-get, but their versions are too old, so we have
# to get updates from pip.RUN pip install pip --upgrade
RUN pip install virtualenv tox yattag##################
# Ruby dependencies# Install rvm
RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
RUN \curl -sSL https://get.rvm.io | bash -s stable# Install Ruby 2.1, Ruby 2.2 and JRuby 1.7
RUN /bin/bash -l -c "rvm install ruby-2.1"
RUN /bin/bash -l -c "rvm install ruby-2.2"
RUN /bin/bash -l -c "rvm install jruby-1.7"
RUN /bin/bash -l -c "echo 'gem: --no-ri --no-rdoc' > ~/.gemrc"
RUN /bin/bash -l -c "echo 'export PATH=/usr/local/rvm/bin:$PATH' >> ~/.bashrc"
RUN /bin/bash -l -c "gem install bundler --no-ri --no-rdoc"

USER 指定当前用户

USER root

USER username

EXPOSE 暴露端口

声明端口，作用是帮助镜像使用者理解这个镜像服务的守护端口，以方便配置映射。在运行时使用随机端口映射时，也就是 docker run -P时，会自动随机映射EXPOSE的端口。

EXPOSE <端口1> [<端口2>...]

在 Dockerfile 中写入这样的声明有两个好处:

1. 一个是帮助镜像使用者理解这个镜像服务的守护端口，以方便配置映射;
2. 另一个用处则是在运行时使用随机端口映射时，也就是 docker run -P 时，会自动随机映射 EXPOSE 的端口。
   例子：

EXPOSE 端口号
EXPOSE 端口号/协议

默认协议是 TCP

EXPOSE 80/tcp
EXPOSE 80/udp

FROM nginx
EXPOSE 80

在docker-compose中

通常在docker-compose中，会通过ports来映射并暴露端口，docker-compose用法如下：

ports:- "8001:80"