dockerfile1

dockerfile介绍

dockerfile是用来构建docker镜像的文件！命令参数脚本！

构建步骤：

1. 编写一个dokerfile文件
2. docker build 构建一个镜像
3. docker run 运行镜像
4. docker push 发布镜像（dckerhub 、阿里云镜像仓库）

dockerfiel构建过程

基础知识：

1. 每个保留关键字（指令）都必须是大写字母
2. 执行从上到下顺序执行
3. #表示注释
4. 每个指令都会创建提交一个新的镜像层，并提交!

dockerfile指令

实战测试

创建一个自己的centos

1.编写dockerfile文件

[root@localhost dockerfile]# cat mydockerfile
FROM centos
MAINTAINER yyds<3069150475@qq.com>

ENV MYPATH /var/local
WORKDIR $MYPATH

RUN rm -rf /etc/yum.repos.d/* && curl -o /etc/yum.repos.d/CentOS-vault-8.5.2111.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
RUN yum -y install vim
RUN yum -y install net-tools

EXPOSE 80

CMD echo $MYPATH
CMD echo "----end----"
CMD /bin/bash

2.通过这个文件构建镜像

[root@localhost dockerfile]# docker build -f dockerfile -t mycentos .

查看代码

 [+] Building 70.2s (6/8)                                  docker:default
[+] Building 70.5s (6/8)                                  docker:default
[+] Building 72.3s (6/8)                                  docker:default
[+] Building 72.6s (6/8)                                  docker:default
[+] Building 117.5s (9/9) FINISHED                        docker:default
 => [internal] load build definition from dockerfile                0.0s
 => => transferring dockerfile: 449B                                0.0s
 => [internal] load metadata for docker.io/library/centos:latest    0.0s
 => [internal] load .dockerignore                                   0.0s
 => => transferring context: 2B                                     0.0s
 => [1/5] FROM docker.io/library/centos:latest                      0.0s
 => CACHED [2/5] WORKDIR /var/local                                 0.0s
 => [3/5] RUN rm -rf /etc/yum.repos.d/* && curl -o /etc/yum.repos  15.9s
 => [4/5] RUN yum -y install vim                                   79.6s
 => [5/5] RUN yum -y install net-tools                             21.7s
 => exporting to image                                              0.3s
 => => exporting layers                                             0.3s
 => => writing image sha256:c7defb0511c187a891e8b504400827c6a54379  0.0s
 => => naming to docker.io/library/mycentos                         0.0s 

构建后的镜像

[root@localhost ~]# docker images
REPOSITORY   TAG       IMAGE ID       CREATED         SIZE
mycentos     latest    c7defb0511c1   3 minutes ago   312MB
centos       latest    5d0da3dc9764   2 years ago     231MB
cmdtest      latest    2b06f9641629   2 years ago     231MB
[root@localhost ~]# docker run -it mycentos
[root@b8511ea46079 local]# ls
[root@b8511ea46079 local]# pwd
/var/local
[root@b8511ea46079 local]# vim a

[1]+  Stopped                 vim a
[root@b8511ea46079 local]# ifconfig
eth0: 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 8  bytes 656 (656.0 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

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        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

查看构建过程

[root@localhost dockerfile]# docker history c7defb0511c1
IMAGE          CREATED          CREATED BY                                      SIZE      COMMENT
c7defb0511c1   12 minutes ago   CMD ["/bin/sh" "-c" "/bin/bash"]                0B        buildkit.dockerfile.v0
<missing>      12 minutes ago   CMD ["/bin/sh" "-c" "echo \"----end----\""]     0B        buildkit.dockerfile.v0
<missing>      12 minutes ago   CMD ["/bin/sh" "-c" "echo $MYPATH"]             0B        buildkit.dockerfile.v0
<missing>      12 minutes ago   EXPOSE map[80/tcp:{}]                           0B        buildkit.dockerfile.v0
<missing>      12 minutes ago   RUN /bin/sh -c yum -y install net-tools # bu…   14.7MB    buildkit.dockerfile.v0
<missing>      12 minutes ago   RUN /bin/sh -c yum -y install vim # buildkit    66.3MB    buildkit.dockerfile.v0
<missing>      13 minutes ago   RUN /bin/sh -c rm -rf /etc/yum.repos.d/* && …   2.5kB     buildkit.dockerfile.v0
<missing>      8 hours ago      WORKDIR /var/local                              0B        buildkit.dockerfile.v0
<missing>      8 hours ago      ENV MYPATH=/var/local                           0B        buildkit.dockerfile.v0
<missing>      8 hours ago      MAINTAINER yyds<3069150475@qq.com>              0B        buildkit.dockerfile.v0
<missing>      2 years ago      /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B
<missing>      2 years ago      /bin/sh -c #(nop)  LABEL org.label-schema.sc…   0B
<missing>      2 years ago      /bin/sh -c #(nop) ADD file:805cb5e15fb6e0bb0…   231MB