Docker镜像创建方法有三种，分别为基于已有镜像创建、基于本地模板创建以及基于Dockerfile创建。
通过Dockerfile创建镜像
这里主要记录下基于Dockerfile创建方法，Dockerfile是由一组指令组成的文件，其中每条指令对应Linux中的一条命令，Docker程序将读取Dockerfile中的指令生成指定镜像。
Dockerfile结构大致分为四个部分：基础镜像信息、维护者信息、镜像操作指令和容器启动时执行指令 。Dockerfile每行支持一条指令，每条指令可带多个参数，支持使用以#号开头的注释。
Docker操作指令
| 指令 | 含义 |
|---|---|
| FROM镜像 | 指定新镜像所基于的镜像，必须为第一条指令 |
| MAINTAINER 名字 | 新镜像的维护人信息 |
| RUN 命令 | 在所基于的镜像上执行命令，并提交到新镜像中 |
| EXPOSE端口号 | 指定新镜像加载到Docker时开启的端口号 |
| ENV 环境变量 变量值 | 设置一个环境变量的值，会被后面的RUN使用 |
| ADD 源文件/目录 目标文件/目录 | 将源文件复制到目标文件，源文件要与Docker位于同一目录下，或者为一个URL |
| COPY 源文件/目录 目标文件/目录 | 将本地主机上的源文件/目录复制到目标地点，源文件/目录要与Dockerfile在同一目录下 |
| VOLUME["目录"] | 在容器中创建一个挂载点 |
| USER 用户名 /UID | 指定运行容器时的用户 |
| WORKDIR 路径 | 为后续的RUN、CMD、ENTRYPOINT指定工作目录 |
| ONBUILD命令 | 指定所生成的镜像作为一个基础镜像时所要运行的命令 |
| CMD["要运行的程序"，"参数1"，"参数2"] | 指定启动容器时运行的命令或脚本，只能有一条CMD命令，多条时只有最后一条被执行 |
以下通过Dockerfile来创建httpd镜像
1.创建镜像工作目录并进入
mkdir apachecd apache/2.创建并编写dockerfile文件
vim Dockerfile
#基于centos镜像FROM centos#维护人的信息MAINTAINER The CentOS Project <303323496@qq.com>#安装httpd软件包RUN yum -y updateRUN yum -y install httpd#开启80端口EXPOSE 80#复制网站首页文件至镜像中web站点下ADD index.html /var/www/html/index.html#复制该脚本至镜像中，并修改其权限ADD run.sh /run.shRUN chmod 775 /run.sh#当启动容器时执行的脚本文件CMD ["/run.sh"]3.创建脚本文件
vim run.sh
#!/bin/bash#清空httpd缓存文件rm -rf /run/httpd/*#启动httpd服务exec /usr/sbin/apachectl -D FOREGROUND4.创建网站首页文件
echo "Thiss is Nginx webapp." > index.html5.查看当前目录文件列表
ls6.通过Dockerfile文件生成镜像
docker build -t httpd:centos .
Sending build context to Docker daemon ?4.096kBStep 1/9 : FROM centos ---> 5182e96772bfStep 2/9 : MAINTAINER The CentOS Project <303323496@qq.com> ---> Running in 6d7c8eae519d ---> 46fc589066ffRemoving intermediate container 6d7c8eae519dStep 3/9 : RUN yum -y update ---> Running in 444105af6041Loaded plugins: fastestmirror, ovlDetermining fastest mirrors * base: mirrors.zju.edu.cn * extras: mirrors.zju.edu.cn * updates: mirrors.cn99.comResolving Dependencies--> Running transaction check---> Package centos-release.x86_64 0:7-5.1804.1.el7.centos will be updated---> Package centos-release.x86_64 0:7-5.1804.4.el7.centos will be an update--> Finished Dependency ResolutionDependencies Resolved================================================================================ Package ????????????Arch ???????Version ????????????????????Repository ???Size================================================================================Updating: centos-release ?????x86_64 ?????7-5.1804.4.el7.centos ??????updates ??????25 kTransaction Summary================================================================================Upgrade ?1 PackageTotal download size: 25 kDownloading packages:Delta RPMs disabled because /usr/bin/applydeltarpm not installed.Public key for centos-release-7-5.1804.4.el7.centos.x86_64.rpm is not installedRetrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7warning: /var/cache/yum/x86_64/7/updates/packages/centos-release-7-5.1804.4.el7.centos.x86_64.rpm:Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEYImporting GPG key 0xF4A80EB5: Userid ????: "CentOS-7 Key (CentOS 7 Official Signing Key) <security@centos.org>" Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5 Package ???: centos-release-7-5.1804.1.el7.centos.x86_64 (@Updates) From ??????: /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7Running transaction checkRunning transaction testTransaction test succeededRunning transaction ?Updating ??: centos-release-7-5.1804.4.el7.centos.x86_64 ?????????????????1/2 ?Cleanup ???: centos-release-7-5.1804.1.el7.centos.x86_64 ?????????????????2/2 ?Verifying ?: centos-release-7-5.1804.4.el7.centos.x86_64 ?????????????????1/2 ?Verifying ?: centos-release-7-5.1804.1.el7.centos.x86_64 ?????????????????2/2Updated: ?centos-release.x86_64 0:7-5.1804.4.el7.centosComplete! ---> 8a4bb67da908Removing intermediate container 444105af6041Step 4/9 : RUN yum -y install httpd ---> Running in 982f008f5f3cLoaded plugins: fastestmirror, ovlLoading mirror speeds from cached hostfile * base: mirrors.zju.edu.cn * extras: mirrors.zju.edu.cn * updates: mirrors.cn99.comResolving Dependencies--> Running transaction check---> Package httpd.x86_64 0:2.4.6-80.el7.centos.1 will be installed--> Processing Dependency: httpd-tools = 2.4.6-80.el7.centos.1 for package: httpd-2.4.6-80.el7.centos.1.x86_64--> Processing Dependency: system-logos >= 7.92.1-1 for package: httpd-2.4.6-80.el7.centos.1.x86_64--> Processing Dependency: /etc/mime.types for package: httpd-2.4.6-80.el7.centos.1.x86_64--> Processing Dependency: libaprutil-1.so.0()(64bit) for package: httpd-2.4.6-80.el7.centos.1.x86_64--> Processing Dependency: libapr-1.so.0()(64bit) for package: httpd-2.4.6-80.el7.centos.1.x86_64--> Running transaction check---> Package apr.x86_64 0:1.4.8-3.el7_4.1 will be installed---> Package apr-util.x86_64 0:1.5.2-6.el7 will be installed---> Package centos-logos.noarch 0:70.0.6-3.el7.centos will be installed---> Package httpd-tools.x86_64 0:2.4.6-80.el7.centos.1 will be installed---> Package mailcap.noarch 0:2.1.41-2.el7 will be installed--> Finished Dependency ResolutionDependencies Resolved================================================================================ Package ??????????Arch ???????Version ??????????????????????Repository ???Size================================================================================Installing: httpd ????????????x86_64 ?????2.4.6-80.el7.centos.1 ????????updates ?????2.7 MInstalling for dependencies: apr ??????????????x86_64 ?????1.4.8-3.el7_4.1 ??????????????base ????????103 k apr-util ?????????x86_64 ?????1.5.2-6.el7 ??????????????????base ?????????92 k centos-logos ?????noarch ?????70.0.6-3.el7.centos ??????????base ?????????21 M httpd-tools ??????x86_64 ?????2.4.6-80.el7.centos.1 ????????updates ??????90 k mailcap ??????????noarch ?????2.1.41-2.el7 ?????????????????base ?????????31 kTransaction Summary================================================================================Install ?1 Package (+5 Dependent packages)Total download size: 24 MInstalled size: 31 MDownloading packages:--------------------------------------------------------------------------------Total ?????????????????????????????????????????????1.1 MB/s | ?24 MB ?00:21Running transaction checkRunning transaction testTransaction test succeededRunning transaction ?Installing : apr-1.4.8-3.el7_4.1.x86_64 ??????????????????????????????????1/6 ?Installing : apr-util-1.5.2-6.el7.x86_64 ?????????????????????????????????2/6 ?Installing : httpd-tools-2.4.6-80.el7.centos.1.x86_64 ????????????????????3/6 ?Installing : centos-logos-70.0.6-3.el7.centos.noarch ?????????????????????4/6 ?Installing : mailcap-2.1.41-2.el7.noarch ?????????????????????????????????5/6 ?Installing : httpd-2.4.6-80.el7.centos.1.x86_64 ??????????????????????????6/6 ?Verifying ?: mailcap-2.1.41-2.el7.noarch ?????????????????????????????????1/6 ?Verifying ?: httpd-tools-2.4.6-80.el7.centos.1.x86_64 ????????????????????2/6 ?Verifying ?: apr-util-1.5.2-6.el7.x86_64 ?????????????????????????????????3/6 ?Verifying ?: httpd-2.4.6-80.el7.centos.1.x86_64 ??????????????????????????4/6 ?Verifying ?: apr-1.4.8-3.el7_4.1.x86_64 ??????????????????????????????????5/6 ?Verifying ?: centos-logos-70.0.6-3.el7.centos.noarch ?????????????????????6/6Installed: ?httpd.x86_64 0:2.4.6-80.el7.centos.1Dependency Installed: ?apr.x86_64 0:1.4.8-3.el7_4.1 ?apr-util.x86_64 0:1.5.2-6.el7 ?centos-logos.noarch 0:70.0.6-3.el7.centos ?httpd-tools.x86_64 0:2.4.6-80.el7.centos.1 ?mailcap.noarch 0:2.1.41-2.el7Complete! ---> d3f0d6f963cbRemoving intermediate container 982f008f5f3cStep 5/9 : EXPOSE 80 ---> Running in b511725feca7 ---> 7f7887f5875eRemoving intermediate container b511725feca7Step 6/9 : ADD index.html /var/www/html/index.html ---> 3c5953c9fd43Removing intermediate container 85dad653f265Step 7/9 : ADD run.sh /run.sh ---> 41980651502bRemoving intermediate container 91ff7e24daa4Step 8/9 : RUN chmod 775 /run.sh ---> Running in 7aebb5d8f194 ---> f673460e23c7Removing intermediate container 7aebb5d8f194Step 9/9 : CMD /run.sh ---> Running in 9c0f5c4f1e32 ---> 551b9fc524baRemoving intermediate container 9c0f5c4f1e32Successfully built 551b9fc524baSuccessfully tagged httpd:centos7.镜像文件加载到容器中运行
docker run -d -p 80:80 --name=httpd httpd:centos8.查看运行中的容器
docker ps9.运行浏览器测试httpd服务
http://192.168.96.44:80【自定义】通过Dockerfile创建httpd镜像
原文地址：http://blog.51cto.com/10316297/2160524