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# 以contes为例 查看 dockerhub 上 contes 的 dockerfileFROM scratchADD centos-7-x86_64-docker.tar.xz /LABEL \  org.label-schema.schema-version="1.0" \  org.label-schema.name="CentOS Base Image" \  org.label-schema.vendor="CentOS" \  org.label-schema.license="GPLv2" \  org.label-schema.build-date="20200809" \  org.opencontainers.image.title="CentOS Base Image" \  org.opencontainers.image.vendor="CentOS" \  org.opencontainers.image.licenses="GPL-2.0-only" \  org.opencontainers.image.created="2020-08-09 00:00:00+01:00"CMD ["/bin/bash"]

DockerFile构建过程

基础知识：

每个保留关键字（指令）都必须是大写字母执行顺序从上到下顺序执行表示注释每个指令都会创建提交一个新的镜像层，并提交

dockerfile是面向开发的，我们以后要发布项目，做镜像，就需要编写dockerfile文件，这个文件十分简单！

Docker镜像逐渐成为企业交付的标准！

DockerFile：构建镜像，定义了一切的步骤，源代码；

DockerImages：通过DockerFile构建生成的一个镜像，这个镜像就是我们最终发布和运行的产品！

Docker容器：容器就是镜像运行起来提供服务！

DockerFile的指令

FROM# 基础镜像MAINTAINER# 镜像是谁写的姓名 + 邮箱RUN# 镜像构建的时候需要运行的命令ADD# 步骤eg:tomcat镜像---》放入tomcat的压缩包！添加内容WORKDIR# 镜像的工作目录VOLUME# 挂载的目录位置EXPOST# 暴露端口配置CMD# 指定这个容器启动的时候要运行的命令,只有最后一个会生效，可被替代ENTRYPOINT# 指定这个容器启动的时候要运行的命令，可以追加命令ONBUILD# 当构建一个被继承的 DockerFile ，这个时候就会运行 ONBUILD 的指令，触发指令COPY# 类似ADD，将我们的文件拷贝到镜像中ENV # 构建的时候设置环境变量

实战测试

Docker Hub 中 99% 的镜像都是从 FROM scratch 这个基础镜像过来的，然后配置我们需要的软件和配置来进行构建

创建一个自己的centos

# 1、编写DockerFile的文件FROM centos# 作者信息MAINTAINER yinxiaodong<m15010969094@163.com># 配置环境变量 ENV MYPATH /user/local# 指定镜像的工作目录WORKDIR $MYPATH  RUN yum install -y vimRUN yum install -y net-tools# 暴露80端口 EXPOSE 80 CMD echo $MYPATHCMD echo "---------end--------"CMD /bin/bash# 2、通过文件构建镜像# 命令 docker build -f dockerfile文件路径-t 镜像名:版本号 .[root@localhost dockerfile]# docker build -f mydockerfile-centos -t mycentos:0.1 .Sending build context to Docker daemon 2.048kBStep 1/9 : FROM centos ---> 0d120b6ccaa8Step 2/9 : MAINTAINER yinxiaodong<m15010969094@163.com> ---> Running in f79b12ffb083Removing intermediate container f79b12ffb083 ---> 8ee53d3f7a65Step 3/9 : ENV MYPATH /user/local ---> Running in 659a2c96d5f7Removing intermediate container 659a2c96d5f7 ---> 59ab131ef44cStep 4/9 : WORKDIR $MYPATH ---> Running in 0b4b8f9c65bbRemoving intermediate container 0b4b8f9c65bb ---> 408b06671488Step 5/9 : RUN yum install -y net-tools ---> Running in 151f81148a87CentOS-8 - AppStream              118 kB/s | 5.8 MB   00:50  CentOS-8 - Base                 218 kB/s | 2.2 MB   00:10  CentOS-8 - Extras                1.8 kB/s | 7.3 kB   00:04  Dependencies resolved.================================================================================ Package     Architecture Version            Repository  Size================================================================================Installing: net-tools    x86_64    2.0-0.51.20160912git.el8    BaseOS    323 kTransaction Summary================================================================================Install 1 PackageTotal download size: 323 kInstalled size: 1.0 MDownloading Packages:net-tools-2.0-0.51.20160912git.el8.x86_64.rpm  219 kB/s | 323 kB   00:01  --------------------------------------------------------------------------------Total                      66 kB/s | 323 kB   00:04   warning: /var/cache/dnf/BaseOS-f6a80ba95cf937f2/packages/net-tools-2.0-0.51.20160912git.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEYCentOS-8 - Base                 162 kB/s | 1.6 kB   00:00  Importing GPG key 0x8483C65D: Userid   : "CentOS (CentOS Official Signing Key) <security@centos.org>" Fingerprint: 99DB 70FA E1D7 CE22 7FB6 4882 05B5 55B3 8483 C65D From    : /etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficialKey imported successfullyRunning transaction checkTransaction check succeeded.Running transaction testTransaction test succeeded.Running transaction Preparing    :                            1/1  Installing    : net-tools-2.0-0.51.20160912git.el8.x86_64       1/1  Running scriptlet: net-tools-2.0-0.51.20160912git.el8.x86_64       1/1  Verifying    : net-tools-2.0-0.51.20160912git.el8.x86_64       1/1 Installed: net-tools-2.0-0.51.20160912git.el8.x86_64                   Complete!Removing intermediate container 151f81148a87 ---> c0a0546c9b2aStep 6/9 : EXPOSE 80 ---> Running in 42000936515dRemoving intermediate container 42000936515d ---> fe68114ecf3fStep 7/9 : CMD echo $MYPATH ---> Running in c393fc53a354Removing intermediate container c393fc53a354 ---> a6924276bf90Step 8/9 : CMD echo "---------end--------" ---> Running in 5994de56f0a1Removing intermediate container 5994de56f0a1 ---> a8ba0ebb3770Step 9/9 : CMD /bin/bash ---> Running in d1fa2d436363Removing intermediate container d1fa2d436363 ---> 41bb76be4884Successfully built 41bb76be4884Successfully tagged mycentos:0.1[root@localhost dockerfile]# docker imagesREPOSITORY      TAG         IMAGE ID      CREATED       SIZEmycentos       0.1         41bb76be4884    7 seconds ago    246MBcentos        1.0         d840628c30a9    6 hours ago     215MBcentos        latest       0d120b6ccaa8    2 days ago     215MB# 启动 mycentos 使用 ifconfig 命令查看ip信息[root@localhost dockerfile]# docker run -it mycentos:0.1[root@494c2bc72263 local]# ifconfigeth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500    inet 172.17.0.3 netmask 255.255.0.0 broadcast 172.17.255.255    ether 02:42:ac:11:00:03 txqueuelen 0 (Ethernet)    RX packets 6 bytes 516 (516.0 B)    RX errors 0 dropped 0 overruns 0 frame 0    TX packets 0 bytes 0 (0.0 B)    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536    inet 127.0.0.1 netmask 255.0.0.0    loop txqueuelen 1000 (Local Loopback)    RX packets 0 bytes 0 (0.0 B)    RX errors 0 dropped 0 overruns 0 frame 0    TX packets 0 bytes 0 (0.0 B)    TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0# 查看所在目录    /user/local 正是我们在dockerfile中指定的目录 [root@494c2bc72263 local]# pwd/user/local

查看镜像的构建历史记录

# 命令 docker history 镜像id[root@localhost ~]# docker history 41bb76be4884IMAGE        CREATED       CREATED BY                   SIZE        COMMENT41bb76be4884    16 minutes ago   /bin/sh -c #(nop) CMD ["/bin/sh" "-c" "/bin…  0B         a8ba0ebb3770    16 minutes ago   /bin/sh -c #(nop) CMD ["/bin/sh" "-c" "echo…  0B         a6924276bf90    16 minutes ago   /bin/sh -c #(nop) CMD ["/bin/sh" "-c" "echo…  0B         fe68114ecf3f    16 minutes ago   /bin/sh -c #(nop) EXPOSE 80          0B         c0a0546c9b2a    16 minutes ago   /bin/sh -c yum install -y net-tools       31.3MB       408b06671488    17 minutes ago   /bin/sh -c #(nop) WORKDIR /user/local      0B         59ab131ef44c    17 minutes ago   /bin/sh -c #(nop) ENV MYPATH=/user/local    0B         8ee53d3f7a65    17 minutes ago   /bin/sh -c #(nop) MAINTAINER yinxiaodong<m1…  0B         0d120b6ccaa8    2 days ago     /bin/sh -c #(nop) CMD ["/bin/bash"]      0B         <missing>      2 days ago     /bin/sh -c #(nop) LABEL org.label-schema.sc…  0B         <missing>      2 days ago     /bin/sh -c #(nop) ADD file:538afc0c5c964ce0d…  215MB

我们平时拿到一个镜像，可以研究一下它是怎么做的---->docker history 镜像id

CMD 和 ENTRYPOINT 的区别

CMD# 指定这个容器启动的时候要运行的命令,只有最后一个会生效，可被替代ENTRYPOINT# 指定这个容器启动的时候要运行的命令，可以追加命令# 测试 CMD# 编写DockerFile的文件[root@localhost dockerfile]# cat dockerfile-cmd-test FROM centosCMD ["ls","-a"]# 根据 DockerFile 构建镜像[root@localhost dockerfile]# docker build -f dockerfile-cmd-test -t testcmd:0.1 .Sending build context to Docker daemon 3.072kBStep 1/2 : FROM centos ---> 0d120b6ccaa8Step 2/2 : CMD ["ls","-a"] ---> Running in b3f8ba72222bRemoving intermediate container b3f8ba72222b ---> 561e47f88730Successfully built 561e47f88730Successfully tagged testcmd:0.1# 构建成功# 查看镜像[root@localhost dockerfile]# docker imagesREPOSITORY      TAG         IMAGE ID      CREATED       SIZEtestcmd        0.1         561e47f88730    6 seconds ago    215MBcentos        latest       0d120b6ccaa8    2 days ago     215MB# 启动镜像 发现ls -a命令生效[root@localhost dockerfile]# docker run -it testcmd:0.1.  .dockerenvdev home lib64    media opt  root sbinsys usr.. binetc lib  lost+found mnt  proc run  srvtmp var# 启动命令中 追加一个 -l, 我们期望的是 ls -a -l,但是 报错，这里将 ls -a 替换成了 -l，最终的命令是 -l 所以报错。[root@localhost dockerfile]# docker run -it 561e47f88730 -ldocker: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"-l\": executable file not found in $PATH": unknown.# 将启动命令替换成 docker run -it testcmd:0.1 ls -al， 成功打印详细信息;[root@localhost dockerfile]# docker run -it testcmd:0.1 ls -altotal 0drwxr-xr-x.  1 root root  6 Aug 13 08:20 .drwxr-xr-x.  1 root root  6 Aug 13 08:20 ..-rwxr-xr-x.  1 root root  0 Aug 13 08:20 .dockerenvlrwxrwxrwx.  1 root root  7 May 11 2019 bin -> usr/bindrwxr-xr-x.  5 root root 360 Aug 13 08:20 devdrwxr-xr-x.  1 root root 66 Aug 13 08:20 etcdrwxr-xr-x.  2 root root  6 May 11 2019 homelrwxrwxrwx.  1 root root  7 May 11 2019 lib -> usr/liblrwxrwxrwx.  1 root root  9 May 11 2019 lib64 -> usr/lib64drwx------.  2 root root  6 Aug 9 21:40 lost+founddrwxr-xr-x.  2 root root  6 May 11 2019 mediadrwxr-xr-x.  2 root root  6 May 11 2019 mntdrwxr-xr-x.  2 root root  6 May 11 2019 optdr-xr-xr-x. 123 root root  0 Aug 13 08:20 procdr-xr-x---.  2 root root 162 Aug 9 21:40 rootdrwxr-xr-x. 11 root root 163 Aug 9 21:40 runlrwxrwxrwx.  1 root root  8 May 11 2019 sbin -> usr/sbindrwxr-xr-x.  2 root root  6 May 11 2019 srvdr-xr-xr-x. 13 root root  0 Aug 11 09:58 sysdrwxrwxrwt.  7 root root 145 Aug 9 21:40 tmpdrwxr-xr-x. 12 root root 144 Aug 9 21:40 usrdrwxr-xr-x. 20 root root 262 Aug 9 21:40 var# 测试二：现在我们把 DockerFile 中 CMD 替换成 ENTRYPOINT 后重新构建，运行 看看结果[root@localhost dockerfile]# cat dockerfile-cmd-test FROM centosENTRYPOINT ["ls","-a"]# 重新构建镜像[root@localhost dockerfile]# docker build -f dockerfile-cmd-test -t testcmd:0.2 .Sending build context to Docker daemon 3.072kBStep 1/2 : FROM centos ---> 0d120b6ccaa8Step 2/2 : ENTRYPOINT ["ls","-a"] ---> Running in c634ca09fabeRemoving intermediate container c634ca09fabe ---> 52d295395f08Successfully built 52d295395f08Successfully tagged testcmd:0.2# 查看镜像[root@localhost dockerfile]# docker imagesREPOSITORY      TAG         IMAGE ID      CREATED       SIZEtestcmd        0.2         52d295395f08    7 seconds ago    215MBtestcmd        0.1         561e47f88730    12 minutes ago   215MBcentos        latest       0d120b6ccaa8    2 days ago     215MB# 运行testcmd：0.2镜像 并追加 -l ,发现 打印出了详细信息[root@localhost dockerfile]# docker run -it testcmd:0.2 -ltotal 0drwxr-xr-x.  1 root root  6 Aug 13 08:17 .drwxr-xr-x.  1 root root  6 Aug 13 08:17 ..-rwxr-xr-x.  1 root root  0 Aug 13 08:17 .dockerenvlrwxrwxrwx.  1 root root  7 May 11 2019 bin -> usr/bindrwxr-xr-x.  5 root root 360 Aug 13 08:17 devdrwxr-xr-x.  1 root root 66 Aug 13 08:17 etcdrwxr-xr-x.  2 root root  6 May 11 2019 homelrwxrwxrwx.  1 root root  7 May 11 2019 lib -> usr/liblrwxrwxrwx.  1 root root  9 May 11 2019 lib64 -> usr/lib64drwx------.  2 root root  6 Aug 9 21:40 lost+founddrwxr-xr-x.  2 root root  6 May 11 2019 mediadrwxr-xr-x.  2 root root  6 May 11 2019 mntdrwxr-xr-x.  2 root root  6 May 11 2019 optdr-xr-xr-x. 121 root root  0 Aug 13 08:17 procdr-xr-x---.  2 root root 162 Aug 9 21:40 rootdrwxr-xr-x. 11 root root 163 Aug 9 21:40 runlrwxrwxrwx.  1 root root  8 May 11 2019 sbin -> usr/sbindrwxr-xr-x.  2 root root  6 May 11 2019 srvdr-xr-xr-x. 13 root root  0 Aug 11 09:58 sysdrwxrwxrwt.  7 root root 145 Aug 9 21:40 tmpdrwxr-xr-x. 12 root root 144 Aug 9 21:40 usrdrwxr-xr-x. 20 root root 262 Aug 9 21:40 var

DockerFile中很多命令都十分相似，我们需要了解他的区别，最好的学习就是对比进行测试查看效果！

实战:Tomcat镜像

1、准备镜像文件 tomcat压缩包 jdk压缩包

[root@localhost tomcat]# ls
apache-tomcat-8.5.43.tar.gz Dockerfile jdk-8u211-linux-x64.tar.gz read.txt

2、编写dockerfile文件, 官方命名Dockerfile，build会自动寻找这个文件，不需要 -f 指定！

# 引入基础FROM centos# 作者信息MAINTAINER yinxiaodoong<m15010969094@163.com># copy文件read.txt到容器的 /usr/local/read.txt 目录下COPY read.txt /usr/local/read.txt# 添加jdk tomcat ---> 自动解压ADD jdk-8u211-linux-x64.tar.gz /usr/local/ADD apache-tomcat-8.5.43.tar.gz /usr/local/# 安装 vim 命令RUN yum install -y vim# 配置 MYPATHENV MYPATH /usr/local/# 指定 进入容器默认路径 /user/local/ WORKDIR $MYPATH# 配置jdk环境变量ENV JAVA_HOME /usr/local/jdk1.8.0_211ENV CLASSPATH $JAVA_HOME/lib/dt.jat:$JAVA_HOME/lib/tools.jar# 配置tomcat环境变量ENV CATALINA_HOME /usr/local/apache-tomcat-8.5.43ENV CATALINA_BASH /usr/local/apache-tomcat-8.5.43ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/lib:$CATALINA_HOME/bin# 暴露8080端口EXPOSE 8080# /usr/local/tomcat/webapps# # 启动容器时 启动tomcatCMD /usr/local/apache-tomcat-8.5.43/bin/startup.sh && tail -f /usr/local/apache-tomcat-8.5.43/logs/catalina.out # 构建tomcat镜像[root@localhost tomcat]# docker build -t mytomcat [root@localhost tomcat]# docker imagesREPOSITORY     TAG         IMAGE ID      CREATED       SIZEmytomcat      latest       a9707559afa1    8 seconds ago    693MBcentos       latest       0d120b6ccaa8    4 days ago     215MB[root@localhost tomcat]# docker run -d -p 8081:8080 --name mytomcat--01 -v /home/yinxiaodong/build/tomcat/test:/usr/local/apache-tomcat-8.5.43/webapps/test -v /home/yinxiaodong/build/tomcat/logs:/usr/local/apache-tomcat-8.5.43/logs mytomcat

发布自己的镜像

发布到 dockerHub

地址https://hub.docker.com/ 注册自己的账号

确定自己的账号可以登录

在我们的服务器上提交

[root@localhost logs]# docker login --helpUsage:docker login [OPTIONS] [SERVER]Log in to a Docker registry.If no server is specified, the default is defined by the daemon.Options: -p, --password string  Password   --password-stdin  Take the password from stdin -u, --username string  Username[root@localhost logs]# [root@localhost logs]# docker login -u xxx -p xxxWARNING! Using --password via the CLI is insecure. Use --password-stdin.WARNING! Your password will be stored unencrypted in /root/.docker/config.json.Configure a credential helper to remove this warning. Seehttps://docs.docker.com/engine/reference/commandline/login/#credentials-storeLogin Succeeded

登录完毕后就可以提交镜像了

[root@localhost logs]# docker push xxx/mytomcat:1.0

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

(责任编辑：admin)