为什么在Ubuntu 16.04上部署Python 3.6、Virtualenv、Flask、GUnicorn时Docker容器映像变得如此大？

Question

在虚拟环境中部署烧瓶应用程序时，python3-m venv FLSK-ENV

Dockerfile：

    FROM appcontainers/ubuntu:xenial

    MAINTAINER user <user>

    RUN apt-get install -y software-properties-common \
            && add-apt-repository ppa:jonathonf/python-3.6 -y \
            && apt-get update -y \
            && apt-get install -y python3.6-minimal python3.6-venv \
            && apt-get install -y git \
            && apt-get install python-pip -y \
            && pip install --upgrade pip \
            && pip install gunicorn \
            && mkdir -p /home/EZMOVE 

    WORKDIR /home/workdir

    RUN git clone -b develop --single-branch http://repo

    RUN ["chmod", "+x", "./prepareenv.sh"]

    RUN /bin/bash -c "source prepareenv.sh"

    EXPOSE 5000

因此，上面的Dockerfile将从“app容器/ubuntu： xenial”中提取最小的ubuntu-16.04，并将仅更新和安装所需的包，例如：

 1. python3.6
 2. git
 3. python-pip
 4. gunicorn

然后它将执行“prepareenv”。要创建python3.6虚拟环境，请激活venv，然后安装需求。txt使用pip，然后它将公开端口，gunicorn将服务于Flask应用程序。。等

但在创建图像时，docker图像大小从70MB增加到550MB。

在安装软件包时，它正在安装其他软件包，如下所示：

    The following additional packages will be installed:
  binutils build-essential bzip2 cpp cpp-5 dpkg-dev fakeroot g++ g++-5 gcc
  gcc-5 gcc-5-base libalgorithm-diff-perl libalgorithm-diff-xs-perl
  libalgorithm-merge-perl libasan2 libatomic1 libc-dev-bin libc6 libc6-dev
  libcc1-0 libcilkrts5 libdpkg-perl libexpat1-dev libfakeroot
  libfile-fcntllock-perl libgcc-5-dev libgomp1 libisl15 libitm1 liblsan0
  libmpc3 libmpfr4 libmpx0 libpython-all-dev libpython-dev libpython-stdlib
  libpython2.7 libpython2.7-dev libpython2.7-minimal libpython2.7-stdlib
  libquadmath0 libstdc++-5-dev libstdc++6 libtsan0 libubsan0 linux-libc-dev
  make manpages manpages-dev python python-all python-all-dev python-dev
  python-minimal python-pkg-resources python-setuptools python-wheel python2.7
  python2.7-dev python2.7-minimal
Suggested packages:
  binutils-doc bzip2-doc cpp-doc gcc-5-locales debian-keyring g++-multilib
  g++-5-multilib gcc-5-doc libstdc++6-5-dbg gcc-multilib autoconf automake
  libtool flex bison gdb gcc-doc gcc-5-multilib libgcc1-dbg libgomp1-dbg
  libitm1-dbg libatomic1-dbg libasan2-dbg liblsan0-dbg libtsan0-dbg
  libubsan0-dbg libcilkrts5-dbg libmpx0-dbg libquadmath0-dbg glibc-doc locales
  libstdc++-5-doc make-doc man-browser python-doc python-tk
  python-setuptools-doc python2.7-doc binfmt-support
The following NEW packages will be installed:
  binutils build-essential bzip2 cpp cpp-5 dpkg-dev fakeroot g++ g++-5 gcc
  gcc-5 libalgorithm-diff-perl libalgorithm-diff-xs-perl
  libalgorithm-merge-perl libasan2 libatomic1 libc-dev-bin libc6-dev libcc1-0
  libcilkrts5 libdpkg-perl libexpat1-dev libfakeroot libfile-fcntllock-perl
  libgcc-5-dev libgomp1 libisl15 libitm1 liblsan0 libmpc3 libmpfr4 libmpx0
  libpython-all-dev libpython-dev libpython-stdlib libpython2.7
  libpython2.7-dev libpython2.7-minimal libpython2.7-stdlib libquadmath0
  libstdc++-5-dev libtsan0 libubsan0 linux-libc-dev make manpages manpages-dev
  python python-all python-all-dev python-dev python-minimal python-pip
  python-pkg-resources python-setuptools python-wheel python2.7 python2.7-dev
  python2.7-minimal
The following packages will be upgraded:
  gcc-5-base libc6 libstdc++6
3 upgraded, 59 newly installed, 0 to remove and 24 not upgraded.
Need to get 76.6 MB of archives.
After this operation, 210 MB of additional disk space will be used.

那么如何减小Docker图像的大小呢？

Answer 1

请尝试以下Dockerfile，它将图像大小减小到255 MB。“--无安装建议”确保只安装了所需的软件包，“rm-rf/var/lib/apt/lists/*”会清除所有索引文件。

FROM appcontainers/ubuntu:xenial

RUN apt-get update \
            && apt-get install -y --no-install-recommends software-properties-common \
            && add-apt-repository -y ppa:jonathonf/python-3.6 \
            && apt-get update \
            && apt-get install -y --no-install-recommends python3.6-minimal python3.6-venv \
            && apt-get install -y --no-install-recommends git \
            && apt-get install -y --no-install-recommends python-pip \
            && pip install --upgrade pip \
            && pip install gunicorn \
            && rm -rf /var/lib/apt/lists/* \
            && mkdir -p /home/EZMOVE

WORKDIR /home/workdir

EXPOSE 5000