如何从图像生成Dockerfile？

Question

是否可以从图像生成Dockerfile？我想了解两个原因:

1. 我可以从存储库下载图像,但希望看到生成它们的配方.

2. 我喜欢保存快照的想法,但是一旦完成,最好有一个结构化的格式来审查所做的事情.

Answer 1

要了解如何构建docker镜像,请使用该 docker history --no-trunc命令.

您可以从图像构建docker文件,但它不包含您想要完全理解图像生成方式的所有内容.合理地提取的是dockerfile的MAINTAINER,ENV,EXPOSE,VOLUME,WORKDIR,ENTRYPOINT,CMD和ONBUILD部分.

以下脚本应该适合您:

#!/bin/bash
docker history --no-trunc "$1" | \
sed -n -e 's,.*/bin/sh -c #(nop) \(MAINTAINER .*[^ ]\) *0 B,\1,p' | \
head -1
docker inspect --format='{{range $e := .Config.Env}}
ENV {{$e}}
{{end}}{{range $e,$v := .Config.ExposedPorts}}
EXPOSE {{$e}}
{{end}}{{range $e,$v := .Config.Volumes}}
VOLUME {{$e}}
{{end}}{{with .Config.User}}USER {{.}}{{end}}
{{with .Config.WorkingDir}}WORKDIR {{.}}{{end}}
{{with .Config.Entrypoint}}ENTRYPOINT {{json .}}{{end}}
{{with .Config.Cmd}}CMD {{json .}}{{end}}
{{with .Config.OnBuild}}ONBUILD {{json .}}{{end}}' "$1"

我使用它作为脚本的一部分来重建运行容器作为图像:https: //github.com/docbill/docker-scripts/blob/master/docker-rebase

如果您希望能够重新打包图像,Dockerfile非常有用.

需要记住的是,docker镜像实际上只能是真实或虚拟机的tar备份.我用这种方式制作了几个码头图像.甚至构建历史也显示我导入了一个巨大的tar文件作为创建图像的第一步......

Answer 2

更新:

引自@ aleung的评论:

centurylink/dockerfile-from-image不适用于新版本的docker.这个对我有用:hub.docker.com/r/chenzj/dfimage

如何从图像生成Dockerfile？

您可以.

第一种方式

$ docker pull centurylink/dockerfile-from-image
$ alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm centurylink/dockerfile-from-image"
$ dfimage --help
Usage: dockerfile-from-image.rb [options] <image_id>
    -f, --full-tree                  Generate Dockerfile for all parent layers
    -h, --help                       Show this message

以下是从现有图像生成Dockerfile的示例 selenium/node-firefox-debug

core@core-01 ~ $ docker pull centurylink/dockerfile-from-image
core@core-01 ~ $ alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm centurylink/dockerfile-from-image"
core@core-01 ~ $ dfimage selenium/node-firefox-debug
ADD file:b43bf069650bac07b66289f35bfdaf474b6b45cac843230a69391a3ee342a273 in /
RUN echo '#!/bin/sh' > /usr/sbin/policy-rc.d    && echo 'exit 101' >> /usr/sbin/policy-rc.d     && chmod +x /usr/sbin/policy-rc.d       && dpkg-divert --local --rename --add /sbin/initctl     && cp -a /usr/sbin/policy-rc.d /sbin/initctl    && sed -i 's/^exit.*/exit 0/' /sbin/initctl         && echo 'force-unsafe-io' > /etc/dpkg/dpkg.cfg.d/docker-apt-speedup         && echo 'DPkg::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };' > /etc/apt/apt.conf.d/docker-clean   && echo 'APT::Update::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };' >> /etc/apt/apt.conf.d/docker-clean   && echo 'Dir::Cache::pkgcache ""; Dir::Cache::srcpkgcache "";' >> /etc/apt/apt.conf.d/docker-clean      && echo 'Acquire::Languages "none";' > /etc/apt/apt.conf.d/docker-no-languages      && echo 'Acquire::GzipIndexes "true"; Acquire::CompressionTypes::Order:: "gz";' > /etc/apt/apt.conf.d/docker-gzip-indexes
RUN sed -i 's/^#\s*\(deb.*universe\)$/\1/g' /etc/apt/sources.list
CMD ["/bin/bash"]
MAINTAINER Selenium <selenium-developers@googlegroups.com>
RUN echo "deb http://archive.ubuntu.com/ubuntu trusty main universe\n" > /etc/apt/sources.list && echo "deb http://archive.ubuntu.com/ubuntu trusty-updates main universe\n" >> /etc/apt/sources.list
RUN apt-get update -qqy && apt-get -qqy --no-install-recommends install ca-certificates openjdk-7-jre-headless unzip wget && rm -rf /var/lib/apt/lists/* && sed -i 's/\/dev\/urandom/\/dev\/.\/urandom/' ./usr/lib/jvm/java-7-openjdk-amd64/jre/lib/security/java.security
RUN mkdir -p /opt/selenium && wget --no-verbose http://selenium-release.storage.googleapis.com/2.46/selenium-server-standalone-2.46.0.jar -O /opt/selenium/selenium-server-standalone.jar
RUN sudo useradd seluser --shell /bin/bash --create-home && sudo usermod -a -G sudo seluser && echo 'ALL ALL = (ALL) NOPASSWD: ALL' >> /etc/sudoers && echo 'seluser:secret' | chpasswd
MAINTAINER Selenium <selenium-developers@googlegroups.com>
ENV DEBIAN_FRONTEND=noninteractive
ENV DEBCONF_NONINTERACTIVE_SEEN=true
ENV TZ=US/Pacific
RUN echo "US/Pacific" | sudo tee /etc/timezone && dpkg-reconfigure --frontend noninteractive tzdata
RUN apt-get update -qqy && apt-get -qqy install xvfb && rm -rf /var/lib/apt/lists/*
COPY file:335d2f6f9bfe311d2b38034ceab3b2ae2a1e07b9b203b330cac9857d6e17c148 in /opt/bin/entry_point.sh
RUN chmod +x /opt/bin/entry_point.sh
ENV SCREEN_WIDTH=1360
ENV SCREEN_HEIGHT=1020
ENV SCREEN_DEPTH=24
ENV DISPLAY=:99.0
USER [seluser]
CMD ["/opt/bin/entry_point.sh"]
MAINTAINER Selenium <selenium-developers@googlegroups.com>
USER [root]
RUN apt-get update -qqy && apt-get -qqy --no-install-recommends install firefox && rm -rf /var/lib/apt/lists/*
COPY file:52a2a815e3bb6b85c5adfbceaabb5665b63f63ef0fb0e3f774624ee399415f84 in /opt/selenium/config.json
USER [seluser]
MAINTAINER Selenium <selenium-developers@googlegroups.com>
USER [root]
RUN apt-get update -qqy && apt-get -qqy install x11vnc && rm -rf /var/lib/apt/lists/* && mkdir -p ~/.vnc && x11vnc -storepasswd secret ~/.vnc/passwd
ENV LANGUAGE=en_US.UTF-8
ENV LANG=en_US.UTF-8
RUN locale-gen en_US.UTF-8 && dpkg-reconfigure --frontend noninteractive locales && apt-get update -qqy && apt-get -qqy --no-install-recommends install language-pack-en && rm -rf /var/lib/apt/lists/*
RUN apt-get update -qqy && apt-get -qqy --no-install-recommends install fonts-ipafont-gothic xfonts-100dpi xfonts-75dpi xfonts-cyrillic xfonts-scalable && rm -rf /var/lib/apt/lists/*
RUN apt-get update -qqy && apt-get -qqy install fluxbox && rm -rf /var/lib/apt/lists/*
COPY file:90e3a7f757c3df44d541b59234ad4ca996f799455eb8d426218619b244ebba68 in /opt/bin/entry_point.sh
RUN chmod +x /opt/bin/entry_point.sh
EXPOSE 5900/tcp

另一种方法,你不需要将图像拉到本地,也不需要运行命令.

使用上面的图像作为示例,您可以通过以下url获取Dockerfile命令:

https://imagelayers.io/?images=selenium%2Fnode-firefox-debug:latest

等一会儿,会有两个窗口,向上窗口列出图层,向下窗口列出Dockerfile中的命令

URL格式为:

https://imagelayers.io/?images=<USER>%2F<IMAGE>:<TAG>

在face中,imagelayers.io是由 Centurylink

Answer 3

我在某种程度上完全错过了接受的答案中的实际命令,所以这里再次,在自己的段落中更加明显,看看有多少人像我一样

$ docker history --no-trunc <IMAGE_ID>

Answer 4

一个bash解决方案:

docker history --no-trunc $argv  | tac | tr -s ' ' | cut -d " " -f 5- | sed 's,^/bin/sh -c #(nop) ,,g' | sed 's,^/bin/sh -c,RUN,g' | sed 's, && ,\n  & ,g' | sed 's,\s*[0-9]*[\.]*[0-9]*[kMG]*B\s*$,,g' | head -n -1

分步说明:

tac : reverse the file
tr -s ' '                                       trim multiple whitespaces into 1
cut -d " " -f 5-                                remove the first fields (until X months/years ago)
sed 's,^/bin/sh -c #(nop) ,,g'                  remove /bin/sh calls for ENV,LABEL...
sed 's,^/bin/sh -c,RUN,g'                       remove /bin/sh calls for RUN
sed 's, && ,\n  & ,g'                           pretty print multi command lines following Docker best practices
sed 's,\s*[0-9]*[\.]*[0-9]*[kMG]*B\s*$,,g'      remove layer size information
head -n -1                                      remove last line ("SIZE COMMENT" in this case)

例:

 ~ ? dih ubuntu:18.04
ADD file:28c0771e44ff530dba3f237024acc38e8ec9293d60f0e44c8c78536c12f13a0b in /
RUN set -xe
   &&  echo '#!/bin/sh' > /usr/sbin/policy-rc.d
   &&  echo 'exit 101' >> /usr/sbin/policy-rc.d
   &&  chmod +x /usr/sbin/policy-rc.d
   &&  dpkg-divert --local --rename --add /sbin/initctl
   &&  cp -a /usr/sbin/policy-rc.d /sbin/initctl
   &&  sed -i 's/^exit.*/exit 0/' /sbin/initctl
   &&  echo 'force-unsafe-io' > /etc/dpkg/dpkg.cfg.d/docker-apt-speedup
   &&  echo 'DPkg::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };' > /etc/apt/apt.conf.d/docker-clean
   &&  echo 'APT::Update::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };' >> /etc/apt/apt.conf.d/docker-clean
   &&  echo 'Dir::Cache::pkgcache ""; Dir::Cache::srcpkgcache "";' >> /etc/apt/apt.conf.d/docker-clean
   &&  echo 'Acquire::Languages "none";' > /etc/apt/apt.conf.d/docker-no-languages
   &&  echo 'Acquire::GzipIndexes "true"; Acquire::CompressionTypes::Order:: "gz";' > /etc/apt/apt.conf.d/docker-gzip-indexes
   &&  echo 'Apt::AutoRemove::SuggestsImportant "false";' > /etc/apt/apt.conf.d/docker-autoremove-suggests
RUN rm -rf /var/lib/apt/lists/*
RUN sed -i 's/^#\s*\(deb.*universe\)$/\1/g' /etc/apt/sources.list
RUN mkdir -p /run/systemd
   &&  echo 'docker' > /run/systemd/container
CMD ["/bin/bash"]

Answer 5

如果您对 Docker hub 注册表中的映像感兴趣并想查看 Dockerfile？。

例子：

如果您想查看图像“jupyter/datascience-notebook”的 Dockerfile，请在浏览器的地址栏中输入“Dockerfile”，如下所示。

https://hub.docker.com/r/jupyter/datascience-notebook/

https://hub.docker.com/r/jupyter/datascience-notebook/Dockerfile

注意：并非所有镜像都有 Dockerfile，例如https://hub.docker.com/r/redislabs/redisinsight/Dockerfile 有时这种方式比在 Github 中搜索 Dockerfile 快得多。

Answer 6

此时不可能(除非图像的作者明确包含Dockerfile).

但是,这绝对是有用的!有两件事有助于获得此功能.

1. 受信任的构建(详见docker-dev讨论
2. 构建过程生成的连续图像中的更详细的元数据.从长远来看,元数据应该指示哪个构建命令产生了图像,这意味着可以从一系列图像重建Dockerfile.

Answer 7

docker pull chenzj/dfimage


alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm chenzj/dfimage"

dfimage image_id

下面是 dfimage 命令的输出：

$ dfimage 0f1947a021ce

FROM node:8
WORKDIR /usr/src/app

COPY file:e76d2e84545dedbe901b7b7b0c8d2c9733baa07cc821054efec48f623e29218c in ./
RUN /bin/sh -c npm install
COPY dir:a89a4894689a38cbf3895fdc0870878272bb9e09268149a87a6974a274b2184a in .

EXPOSE 8080
CMD ["npm" "start"]

Answer 8

这是从@ fallino的回答得出，通过使用输出格式选择一些调整和简化泊坞窗的历史。由于 macOS 和 Gnu/Linux 具有不同的命令行实用程序，因此 Mac 需要不同的版本。如果您只需要一个或另一个，您可以只使用这些行。

#!/bin/bash
case "$OSTYPE" in
    linux*)
        docker history --no-trunc --format "{{.CreatedBy}}" $1 | # extract information from layers
        tac                                                    | # reverse the file
        sed 's,^\(|3.*\)\?/bin/\(ba\)\?sh -c,RUN,'             | # change /bin/(ba)?sh calls to RUN
        sed 's,^RUN #(nop) *,,'                                | # remove RUN #(nop) calls for ENV,LABEL...
        sed 's,  *&&  *, \\\n \&\& ,g'                           # pretty print multi command lines following Docker best practices
    ;;
    darwin*)
        docker history --no-trunc --format "{{.CreatedBy}}" $1 | # extract information from layers
        tail -r                                                | # reverse the file
        sed -E 's,^(\|3.*)?/bin/(ba)?sh -c,RUN,'               | # change /bin/(ba)?sh calls to RUN
        sed 's,^RUN #(nop) *,,'                                | # remove RUN #(nop) calls for ENV,LABEL...
        sed $'s,  *&&  *, \\\ \\\n \&\& ,g'                      # pretty print multi command lines following Docker best practices
    ;;
    *)
        echo "unknown OSTYPE: $OSTYPE"
    ;;
esac

Answer 9

更新2018年12月至宝马的答案

docker pull chenzj/dfimage
alias dfimage="docker run -v /var/run/docker.sock:/var/run/docker.sock --rm chenzj/dfimage"
dfimage IMAGE_ID > Dockerfile