docker镜像构建详细说明

小鱼儿 2022-10-07 15:43 205阅读 0赞

### 文章目录 ###

*  说明
 *  镜像编辑【常用说明】
 *   *  查找命令依赖的包
     *  编辑镜像文件【基础使用流程说明】
     *   *  编辑镜像文件【注意事项说明】
     *  编辑镜像文件【ADD与COPY增加文件】
     *  编辑镜像文件【EXPOSE指定端口】
     *  编辑镜像文件【ENV指定变量】
     *  编辑镜像文件【USER指定用户】
     *  编辑镜像文件【VOLUME 持久化目录】
 *  搭建一个ssh服务器
 *   *  dockerfile文件内容和编译过程如下
     *  创建容器使用测试

# 说明 #

*  镜像构建并不是一个从零到有的过程–，而是从一个已经存在的镜像的基础上，开始进  
    行修改。
 *  比如，想要一个自定义的centos镜像，这镜像里面有自己想要的服务或命令，那么就得先有一个centos镜像，这个镜像可以直接从官网这些渠道获取，这个镜像就称之为基础镜像。 然后我们在基础镜像上通过dockerfile增加功能，得到一个新的终版镜像。
 *  如：我们从网易云下载的一个centos镜像，这个镜像的命令很少，连最基本的ip a和ifconfig命令都没有，后面我们就以这个镜像增加这2命令为例。  
    下面中我创建一个退出就自动删除的centos容器【为了确定上面是没这2个命令的】

[root@ccx ~]# docker images | grep cen
    hub.c.163.com/library/centos      latest    328edcd84f1b   3 years ago   193MB
    [root@ccx ~]# docker run -it --rm hub.c.163.com/library/centos
    [root@bed2a3aa0268 /]# ip a 
    bash: ip: command not found
    [root@bed2a3aa0268 /]# ifconfig
    bash: ifconfig: command not found
    [root@903b38da3748 /]# cat /etc/redhat-release 
    CentOS Linux release 7.3.1611 (Core) 
    [root@903b38da3748 /]# 
    [root@bed2a3aa0268 /]# exit
    exit
    [root@ccx ~]#

# 镜像编辑【常用说明】 #

## 查找命令依赖的包 ##

*  我们要安装ifconfig和ip命令，首先就得知道这2命令的包是啥  
    我们可以去有这个命令的主机上，执行下面命令即可看到了。

[root@ccx ~]# rpm -qf `which ifconfig`
    net-tools-2.0-0.24.20131004git.el7.x86_64
    [root@ccx ~]# rpm -qf `which ip`
    iproute-4.11.0-14.el7.x86_64
    [root@ccx ~]#

## 编辑镜像文件【基础使用流程说明】 ##

*  在任意位置编辑一个配置文件：`Dockerfile`

[root@ccx ~]# pwd
    /root
    [root@ccx ~]# cat Dockerfile 
    FROM hub.c.163.com/library/centos
    MAINTAINER ccx
    
    RUN yum install net-tools -y
    RUN yum install iproute -y
    
    CMD ["/bin/bash"]
    [root@ccx ~]#

*  参数说明
 *  `FROM`：后面跟的是镜像的名称，如果现在有的话，就用命令docker images查看，然后复制名称过来即可，如果没有的话，可以输入一个centos，然后系统会自动从网上拉取这个镜像【建议还是先自行下载，然后复制镜像名称过来】
 *  `MAINTAINER`： 后面跟的是介绍说明，跟啥内容都行。
 *  `RUN`：后面跟的是需要执行的命令操作，就是当镜像启动前会执行这些命令【这个RUN不是越多越好，后面会做说明的】
 *  `CMD[" "]`：这里面放的是编译器，centos的就是/bin/bash了
 *  编译前先查看一个文件值是不是为1【如果不是1的话，下面镜像编译会卡住，无法成功】

[root@ccx ~]# cat /proc/sys/net/ipv4/ip_forward
    1
    [root@ccx ~]#
    # 如果上面的值不是1，那么就执行下面命令
    [root@ccx ~]# echo 1 > /proc/sys/net/ipv4/ip_forward

*  上面的文件编译完成以后，就要开始编译镜像了  
    命令格式：`docker build -t REPOSITORY名称：TAG名称 Dockerfile文件路径 -f Dockerfile名称`【默认是Dockerfile文件，如果只有一个默认文件，那么-f就不需要加了】  
    如：`docker build -t centos:v1 .` 【. 表示当前路径啊】，编译过程如下

[root@ccx ~]# docker build -t centos:v1 .
    Sending build context to Docker daemon  1.177GB
    Step 1/5 : FROM hub.c.163.com/library/centos
     ---> 328edcd84f1b
    Step 2/5 : MAINTAINER ccx
     ---> Running in 11d69d710d74
    Removing intermediate container 11d69d710d74
     ---> cf8f1b1f7f64
    Step 3/5 : RUN yum install net-tools -y
     ---> Running in fec2cd515930
    Loaded plugins: fastestmirror, ovl
    Determining fastest mirrors
     * base: mirrors.aliyun.com
     * extras: mirrors.aliyun.com
     * updates: mirrors.aliyun.com
    Resolving Dependencies
    --> Running transaction check
    ---> Package net-tools.x86_64 0:2.0-0.25.20131004git.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package         Arch         Version                          Repository  Size
    ================================================================================
    Installing:
     net-tools       x86_64       2.0-0.25.20131004git.el7         base       306 k
    
    Transaction Summary
    ================================================================================
    Install  1 Package
    
    Total download size: 306 k
    Installed size: 917 k
    Downloading packages:
    warning: /var/cache/yum/x86_64/7/base/packages/net-tools-2.0-0.25.20131004git.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
    Public key for net-tools-2.0-0.25.20131004git.el7.x86_64.rpm is not installed
    Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    Importing 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-7-3.1611.el7.centos.x86_64 (@CentOS)
     From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : net-tools-2.0-0.25.20131004git.el7.x86_64                    1/1 
      Verifying  : net-tools-2.0-0.25.20131004git.el7.x86_64                    1/1 
    
    Installed:
      net-tools.x86_64 0:2.0-0.25.20131004git.el7                                   
    
    Complete!
    Removing intermediate container fec2cd515930
     ---> 652b957f8a8b
    Step 4/5 : RUN yum install iproute -y
     ---> Running in 69691bc80819
    Loaded plugins: fastestmirror, ovl
    Loading mirror speeds from cached hostfile
     * base: mirrors.aliyun.com
     * extras: mirrors.aliyun.com
     * updates: mirrors.aliyun.com
    Resolving Dependencies
    --> Running transaction check
    ---> Package iproute.x86_64 0:4.11.0-30.el7 will be installed
    --> Processing Dependency: libmnl.so.0(LIBMNL_1.0)(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Processing Dependency: libxtables.so.10()(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Processing Dependency: libmnl.so.0()(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Running transaction check
    ---> Package iptables.x86_64 0:1.4.21-35.el7 will be installed
    --> Processing Dependency: libnfnetlink.so.0()(64bit) for package: iptables-1.4.21-35.el7.x86_64
    --> Processing Dependency: libnetfilter_conntrack.so.3()(64bit) for package: iptables-1.4.21-35.el7.x86_64
    ---> Package libmnl.x86_64 0:1.0.3-7.el7 will be installed
    --> Running transaction check
    ---> Package libnetfilter_conntrack.x86_64 0:1.0.6-1.el7_3 will be installed
    ---> Package libnfnetlink.x86_64 0:1.0.1-4.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package                      Arch         Version             Repository  Size
    ================================================================================
    Installing:
     iproute                      x86_64       4.11.0-30.el7       base       805 k
    Installing for dependencies:
     iptables                     x86_64       1.4.21-35.el7       base       432 k
     libmnl                       x86_64       1.0.3-7.el7         base        23 k
     libnetfilter_conntrack       x86_64       1.0.6-1.el7_3       base        55 k
     libnfnetlink                 x86_64       1.0.1-4.el7         base        26 k
    
    Transaction Summary
    ================================================================================
    Install  1 Package (+4 Dependent packages)
    
    Total download size: 1.3 M
    Installed size: 3.5 M
    Downloading packages:
    --------------------------------------------------------------------------------
    Total                                              1.8 MB/s | 1.3 MB  00:00     
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : libmnl-1.0.3-7.el7.x86_64                                    1/5 
      Installing : libnfnetlink-1.0.1-4.el7.x86_64                              2/5 
      Installing : libnetfilter_conntrack-1.0.6-1.el7_3.x86_64                  3/5 
      Installing : iptables-1.4.21-35.el7.x86_64                                4/5 
      Installing : iproute-4.11.0-30.el7.x86_64                                 5/5 
      Verifying  : libnfnetlink-1.0.1-4.el7.x86_64                              1/5 
      Verifying  : libnetfilter_conntrack-1.0.6-1.el7_3.x86_64                  2/5 
      Verifying  : iptables-1.4.21-35.el7.x86_64                                3/5 
      Verifying  : libmnl-1.0.3-7.el7.x86_64                                    4/5 
      Verifying  : iproute-4.11.0-30.el7.x86_64                                 5/5 
    
    Installed:
      iproute.x86_64 0:4.11.0-30.el7                                                
    
    Dependency Installed:
      iptables.x86_64 0:1.4.21-35.el7                                               
      libmnl.x86_64 0:1.0.3-7.el7                                                   
      libnetfilter_conntrack.x86_64 0:1.0.6-1.el7_3                                 
      libnfnetlink.x86_64 0:1.0.1-4.el7                                             
    
    Complete!
    Removing intermediate container 69691bc80819
     ---> 443471b80ff2
    Step 5/5 : CMD ["/bin/bash"]
     ---> Running in 7135ecfff344
    Removing intermediate container 7135ecfff344
     ---> 4105c41a4cc1
    Successfully built 4105c41a4cc1
    Successfully tagged centos:v1

*  编译完成以后可以通过查看镜像看到我们制作的这个镜像了  
    然后查看详细可以看到 前4项就是我们自定义的内容了

[root@ccx ~]# docker images
    REPOSITORY                        TAG       IMAGE ID       CREATED              SIZE
    centos                            v1        4105c41a4cc1   About a minute ago   433MB
    nginx                             latest    d1a364dc548d   3 weeks ago          133MB
    hub.c.163.com/library/wordpress   latest    dccaeccfba36   3 years ago          406MB
    hub.c.163.com/library/centos      latest    328edcd84f1b   3 years ago          193MB
    hub.c.163.com/library/mysql       latest    9e64176cd8a2   4 years ago          407MB
    [root@ccx ~]# 
    [root@ccx ~]# docker history centos:v1 
    IMAGE          CREATED         CREATED BY                                      SIZE      COMMENT
    4105c41a4cc1   3 minutes ago   /bin/sh -c #(nop) CMD ["/bin/bash"] 0B 
    443471b80ff2   3 minutes ago   /bin/sh -c yum install iproute -y               121MB     
    652b957f8a8b   3 minutes ago   /bin/sh -c yum install net-tools -y             119MB     
    cf8f1b1f7f64   4 minutes ago   /bin/sh -c #(nop) MAINTAINER ccx 0B 
    328edcd84f1b   3 years ago     /bin/sh -c #(nop) CMD ["/bin/bash"] 0B 
    <missing>      3 years ago     /bin/sh -c #(nop) LABEL name=CentOS Base Im… 0B 
    <missing>      3 years ago     /bin/sh -c #(nop) ADD file:63492ba809361c51e… 193MB 
    [root@ccx ~]#

*  现在通过这个镜像生成容器测试  
    可以看到这个镜像中这2命令确实有了

[root@ccx ~]# docker run -it --rm centos:v1 
    [root@0508e306c79d /]# ip a 
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
           valid_lft forever preferred_lft forever
    16: eth0@if17: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
        link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
        inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
           valid_lft forever preferred_lft forever
    [root@0508e306c79d /]# ifconfig
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
            ether 02:42:ac:11:00:02  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 0
    
    lo: 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
    
    [root@0508e306c79d /]#

### 编辑镜像文件【注意事项说明】 ###

*  上面的`Dockerfile`配置文件中，每多写一个`RUN`，所生成的镜像都会多一层`layer`，这样就会导致生成的镜像很大，所以我们尽可能的只写一个`RUN`让这些命令全部实现，所以修改后如下咯。
 *  我们可以将Dockerfile文件修改为如下  
    `&&`是与的意思，就是前面执行完了执行后面的命令， `\`是换行的意思【后面不能有空格哈】，如果有很多命令需要执行，则加很多 `&& \`就是了【这样是为了美观】

[root@ccx ~]# cat Dockerfile 
    FROM hub.c.163.com/library/centos
    MAINTAINER ccx
    
    RUN yum install net-tools -y && \
        yum install iproute -y
    
    CMD ["/bin/bash"]
    [root@ccx ~]#

*  然后我们重新生成一个 centos:v2版本  
    `docker build -t centos:v2 .`  
    过程如下

[root@ccx ~]# docker build -t centos:v2 .
    Sending build context to Docker daemon  1.177GB
    Step 1/4 : FROM hub.c.163.com/library/centos
     ---> 328edcd84f1b
    Step 2/4 : MAINTAINER ccx
     ---> Using cache
     ---> cf8f1b1f7f64
    Step 3/4 : RUN yum install net-tools -y &&     yum install iproute -y
     ---> Running in 4ed42d93dd76
    Loaded plugins: fastestmirror, ovl
    Determining fastest mirrors
     * base: mirrors.aliyun.com
     * extras: mirrors.aliyun.com
     * updates: mirrors.aliyun.com
    Resolving Dependencies
    --> Running transaction check
    ---> Package net-tools.x86_64 0:2.0-0.25.20131004git.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package         Arch         Version                          Repository  Size
    ================================================================================
    Installing:
     net-tools       x86_64       2.0-0.25.20131004git.el7         base       306 k
    
    Transaction Summary
    ================================================================================
    Install  1 Package
    
    Total download size: 306 k
    Installed size: 917 k
    Downloading packages:
    warning: /var/cache/yum/x86_64/7/base/packages/net-tools-2.0-0.25.20131004git.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
    Public key for net-tools-2.0-0.25.20131004git.el7.x86_64.rpm is not installed
    Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    Importing 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-7-3.1611.el7.centos.x86_64 (@CentOS)
     From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : net-tools-2.0-0.25.20131004git.el7.x86_64                    1/1 
      Verifying  : net-tools-2.0-0.25.20131004git.el7.x86_64                    1/1 
    
    Installed:
      net-tools.x86_64 0:2.0-0.25.20131004git.el7                                   
    
    Complete!
    Loaded plugins: fastestmirror, ovl
    Loading mirror speeds from cached hostfile
     * base: mirrors.aliyun.com
     * extras: mirrors.aliyun.com
     * updates: mirrors.aliyun.com
    Resolving Dependencies
    --> Running transaction check
    ---> Package iproute.x86_64 0:4.11.0-30.el7 will be installed
    --> Processing Dependency: libmnl.so.0(LIBMNL_1.0)(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Processing Dependency: libxtables.so.10()(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Processing Dependency: libmnl.so.0()(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Running transaction check
    ---> Package iptables.x86_64 0:1.4.21-35.el7 will be installed
    --> Processing Dependency: libnfnetlink.so.0()(64bit) for package: iptables-1.4.21-35.el7.x86_64
    --> Processing Dependency: libnetfilter_conntrack.so.3()(64bit) for package: iptables-1.4.21-35.el7.x86_64
    ---> Package libmnl.x86_64 0:1.0.3-7.el7 will be installed
    --> Running transaction check
    ---> Package libnetfilter_conntrack.x86_64 0:1.0.6-1.el7_3 will be installed
    ---> Package libnfnetlink.x86_64 0:1.0.1-4.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package                      Arch         Version             Repository  Size
    ================================================================================
    Installing:
     iproute                      x86_64       4.11.0-30.el7       base       805 k
    Installing for dependencies:
     iptables                     x86_64       1.4.21-35.el7       base       432 k
     libmnl                       x86_64       1.0.3-7.el7         base        23 k
     libnetfilter_conntrack       x86_64       1.0.6-1.el7_3       base        55 k
     libnfnetlink                 x86_64       1.0.1-4.el7         base        26 k
    
    Transaction Summary
    ================================================================================
    Install  1 Package (+4 Dependent packages)
    
    Total download size: 1.3 M
    Installed size: 3.5 M
    Downloading packages:
    --------------------------------------------------------------------------------
    Total                                              1.6 MB/s | 1.3 MB  00:00     
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : libmnl-1.0.3-7.el7.x86_64                                    1/5 
      Installing : libnfnetlink-1.0.1-4.el7.x86_64                              2/5 
      Installing : libnetfilter_conntrack-1.0.6-1.el7_3.x86_64                  3/5 
      Installing : iptables-1.4.21-35.el7.x86_64                                4/5 
      Installing : iproute-4.11.0-30.el7.x86_64                                 5/5 
      Verifying  : libnfnetlink-1.0.1-4.el7.x86_64                              1/5 
      Verifying  : libnetfilter_conntrack-1.0.6-1.el7_3.x86_64                  2/5 
      Verifying  : iptables-1.4.21-35.el7.x86_64                                3/5 
      Verifying  : libmnl-1.0.3-7.el7.x86_64                                    4/5 
      Verifying  : iproute-4.11.0-30.el7.x86_64                                 5/5 
    
    Installed:
      iproute.x86_64 0:4.11.0-30.el7                                                
    
    Dependency Installed:
      iptables.x86_64 0:1.4.21-35.el7                                               
      libmnl.x86_64 0:1.0.3-7.el7                                                   
      libnetfilter_conntrack.x86_64 0:1.0.6-1.el7_3                                 
      libnfnetlink.x86_64 0:1.0.1-4.el7                                             
    
    Complete!
    Removing intermediate container 4ed42d93dd76
     ---> 7e5ab683bf8b
    Step 4/4 : CMD ["/bin/bash"]
     ---> Running in 60f0fa6c3965
    Removing intermediate container 60f0fa6c3965
     ---> 6f27209158df
    Successfully built 6f27209158df
    Successfully tagged centos:v2
    [root@ccx ~]#

*  和基础使用创建结果对比  
    只有一个run以后镜像大小明显小了很多，下面TAG的v2是只有一个run创建的

[root@ccx ~]# docker images
    REPOSITORY                        TAG       IMAGE ID       CREATED          SIZE
    centos                            v2        6f27209158df   2 minutes ago    315MB
    centos                            v1        4105c41a4cc1   13 minutes ago   433MB

*  创建容器测试结果  
    ifconfig和ip a命令依然是有的。

[root@ccx ~]# docker run -it --rm centos:v2
    [root@20f2597f6246 /]# ifconfig
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
            ether 02:42:ac:11:00:02  txqueuelen 0  (Ethernet)
            RX packets 3  bytes 266 (266.0 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
            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
    
    [root@20f2597f6246 /]# ip a 
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
           valid_lft forever preferred_lft forever
    20: eth0@if21: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
        link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
        inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
           valid_lft forever preferred_lft forever
    [root@20f2597f6246 /]#

## 编辑镜像文件【ADD与COPY增加文件】 ##

*  ADD和COPY的区别
    
     *  `ADD`和`COPY`是作用是一样的,都是用于文件拷贝
     *  但`ADD`带有自动解压功能，适用于拷贝多个文件，拷贝前将这些文件打成一个tar包即可】
     *  `COPY`没有自动解压功能，适用于拷贝单个文件，不用做任何操作【不需要打tar包操作】，但COPY也可以拷贝tar包到容器，只是容器里看到的依然是tar包，不会自动解压罢了。
     *  所以，如果文件多，打成tar包用ADD拷贝，如果仅有一个文件，则用COPY直接拷贝，他们的使用方法是一样的。
 *  这个依然是基于`Dockerfile`文件实现的功能。
 *  ADD使用方法：`ADD tar包文件名 路径` ，就是将指定文件拷贝到指定容器的路径里面  
    注：tar包文件必须和dockerfile在一个目录中
 *  COPY使用方法：`COPY 文件名 路径` ，就是将指定文件拷贝到指定容器的路径里面  
    注：需要拷贝的文件必须和dockerfile再在一个目录中
 *  如：我们将容器中的yum源替换为本机的yum源为例  
    我们先将本地的yum源打成tar包并放在和Dockerfile文件一个目录

[root@ccx ~]# cd /etc/yum.repos.d/
    [root@ccx yum.repos.d]# ls
    bak  CentOS-Base.repo  docker-ce.repo  epel.repo  k8s.repo
    [root@ccx yum.repos.d]# tar zcf repo.tar.gz *.repo
    [root@ccx yum.repos.d]# mv repo.tar.gz /root
    mv: overwrite ‘/root/repo.tar.gz’? y
    [root@ccx yum.repos.d]# cd /root
    [root@ccx ~]# ls | grep rep
    repo.tar.gz
    [root@ccx ~]# 
    [root@ccx ~]# tar tf repo.tar.gz 
    CentOS-Base.repo
    docker-ce.repo
    epel.repo
    k8s.repo
    [root@ccx ~]#

*  然后修改Dockerfile文件  
    添加文件之前需要先删除原来镜像中的源路径文件，所以需要先定义一个RUN用来删除文件，然后再这个文件下面 添加一个ADD，将文件拷贝到yum文件中【RUN分开的原因是需要先配置完毕yum才能使用yum install】

[root@ccx ~]# cat Dockerfile
    FROM hub.c.163.com/library/centos
    MAINTAINER ccx
    
    RUN rm -rf /etc/yum.repos.d/*
    
    ADD repo.tar.gz /etc/yum.repos.d/
    
    RUN yum install net-tools -y && \
        yum install iproute -y
    
    CMD ["/bin/bash"]
    [root@ccx ~]#

*  上面文件保存后重新编译一次，名称为centos:v3，过程如下

[root@ccx ~]# yum build -t centos:v3 .
    Loaded plugins: fastestmirror, langpacks
    No such command: build. Please use /usr/bin/yum --help
    [root@ccx ~]# docker build -t centos:v3 .
    Sending build context to Docker daemon  1.177GB
    Step 1/6 : FROM hub.c.163.com/library/centos
     ---> 328edcd84f1b
    Step 2/6 : MAINTAINER ccx
     ---> Using cache
     ---> cf8f1b1f7f64
    Step 3/6 : RUN rm -rf /etc/yum.repos.d/*
     ---> Running in 8eb8c344528c
    Removing intermediate container 8eb8c344528c
     ---> e74a3061df3a
    Step 4/6 : ADD repo.tar.gz /etc/yum.repos.d/
     ---> 80fe76f4a233
    Step 5/6 : RUN yum install net-tools -y &&     yum install iproute -y
     ---> Running in 6277b3c234a9
    Loaded plugins: fastestmirror, ovl
    Retrieving key from https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
    Importing GPG key 0x307EA071:
     Userid     : "Rapture Automatic Signing Key (cloud-rapture-signing-key-2021-03-01-08_01_09.pub)"
     Fingerprint: 7f92 e05b 3109 3bef 5a3c 2d38 feea 9169 307e a071
     From       : https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
    Retrieving key from https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
    Determining fastest mirrors
    Resolving Dependencies
    --> Running transaction check
    ---> Package net-tools.x86_64 0:2.0-0.25.20131004git.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package         Arch         Version                          Repository  Size
    ================================================================================
    Installing:
     net-tools       x86_64       2.0-0.25.20131004git.el7         base       306 k
    
    Transaction Summary
    ================================================================================
    Install  1 Package
    
    Total download size: 306 k
    Installed size: 917 k
    Downloading packages:
    warning: /var/cache/yum/x86_64/7/base/packages/net-tools-2.0-0.25.20131004git.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
    Public key for net-tools-2.0-0.25.20131004git.el7.x86_64.rpm is not installed
    Retrieving key from http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
    Importing 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
     From       : http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : net-tools-2.0-0.25.20131004git.el7.x86_64                    1/1 
      Verifying  : net-tools-2.0-0.25.20131004git.el7.x86_64                    1/1 
    
    Installed:
      net-tools.x86_64 0:2.0-0.25.20131004git.el7                                   
    
    Complete!
    Loaded plugins: fastestmirror, ovl
    Loading mirror speeds from cached hostfile
    Resolving Dependencies
    --> Running transaction check
    ---> Package iproute.x86_64 0:4.11.0-30.el7 will be installed
    --> Processing Dependency: libmnl.so.0(LIBMNL_1.0)(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Processing Dependency: libxtables.so.10()(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Processing Dependency: libmnl.so.0()(64bit) for package: iproute-4.11.0-30.el7.x86_64
    --> Running transaction check
    ---> Package iptables.x86_64 0:1.4.21-35.el7 will be installed
    --> Processing Dependency: libnfnetlink.so.0()(64bit) for package: iptables-1.4.21-35.el7.x86_64
    --> Processing Dependency: libnetfilter_conntrack.so.3()(64bit) for package: iptables-1.4.21-35.el7.x86_64
    ---> Package libmnl.x86_64 0:1.0.3-7.el7 will be installed
    --> Running transaction check
    ---> Package libnetfilter_conntrack.x86_64 0:1.0.6-1.el7_3 will be installed
    ---> Package libnfnetlink.x86_64 0:1.0.1-4.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package                      Arch         Version             Repository  Size
    ================================================================================
    Installing:
     iproute                      x86_64       4.11.0-30.el7       base       805 k
    Installing for dependencies:
     iptables                     x86_64       1.4.21-35.el7       base       432 k
     libmnl                       x86_64       1.0.3-7.el7         base        23 k
     libnetfilter_conntrack       x86_64       1.0.6-1.el7_3       base        55 k
     libnfnetlink                 x86_64       1.0.1-4.el7         base        26 k
    
    Transaction Summary
    ================================================================================
    Install  1 Package (+4 Dependent packages)
    
    Total download size: 1.3 M
    Installed size: 3.5 M
    Downloading packages:
    --------------------------------------------------------------------------------
    Total                                              2.7 MB/s | 1.3 MB  00:00     
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : libmnl-1.0.3-7.el7.x86_64                                    1/5 
      Installing : libnfnetlink-1.0.1-4.el7.x86_64                              2/5 
      Installing : libnetfilter_conntrack-1.0.6-1.el7_3.x86_64                  3/5 
      Installing : iptables-1.4.21-35.el7.x86_64                                4/5 
      Installing : iproute-4.11.0-30.el7.x86_64                                 5/5 
      Verifying  : libnfnetlink-1.0.1-4.el7.x86_64                              1/5 
      Verifying  : libnetfilter_conntrack-1.0.6-1.el7_3.x86_64                  2/5 
      Verifying  : iptables-1.4.21-35.el7.x86_64                                3/5 
      Verifying  : libmnl-1.0.3-7.el7.x86_64                                    4/5 
      Verifying  : iproute-4.11.0-30.el7.x86_64                                 5/5 
    
    Installed:
      iproute.x86_64 0:4.11.0-30.el7                                                
    
    Dependency Installed:
      iptables.x86_64 0:1.4.21-35.el7                                               
      libmnl.x86_64 0:1.0.3-7.el7                                                   
      libnetfilter_conntrack.x86_64 0:1.0.6-1.el7_3                                 
      libnfnetlink.x86_64 0:1.0.1-4.el7                                             
    
    Complete!
    Removing intermediate container 6277b3c234a9
     ---> 2b86e5699766
    Step 6/6 : CMD ["/bin/bash"]
     ---> Running in 1e6ff2ac0399
    Removing intermediate container 1e6ff2ac0399
     ---> 0212a1a45667
    Successfully built 0212a1a45667
    Successfully tagged centos:v3
    [root@ccx ~]#

*  创建容器测试  
    可以看到yum源文件已经边了，且命令已经安装成功了

[root@ccx ~]# docker images
    REPOSITORY                        TAG       IMAGE ID       CREATED          SIZE
    centos                            v3        0212a1a45667   3 minutes ago    357MB
    centos                            v2        6f27209158df   27 minutes ago   315MB
    centos                            v1        4105c41a4cc1   38 minutes ago   433MB
    [root@ccx ~]# docker run -it --rm centos:v3 
    [root@020e9637b5e3 /]# ls /etc/yum.repos.d/
    CentOS-Base.repo  docker-ce.repo  epel.repo  k8s.repo
    [root@020e9637b5e3 /]# ifconfig
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
            ether 02:42:ac:11:00:02  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
            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
    
    [root@020e9637b5e3 /]# ip a 
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
           valid_lft forever preferred_lft forever
    26: eth0@if27: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
        link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
        inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
           valid_lft forever preferred_lft forever
    [root@020e9637b5e3 /]#

## 编辑镜像文件【EXPOSE指定端口】 ##

*  使用方法：`EXPOSE 端口号1 端口号2 端口号3`
 *  这个我们以nginx服务为例【镜像使用我们上面创建的centos:v3】  
    并且这个nginx的CMD文件比较特别，我们可以查看镜像现有的CMD，然后复制过去就行了  
    先查看到nginx镜像的CMD路径

[root@ccx ~]# docker history nginx:latest --no-trunc| head -n 2
    IMAGE                                                                     CREATED       CREATED BY                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  SIZE      COMMENT
    sha256:d1a364dc548d5357f0da3268c888e1971bbdb957ee3f028fe7194f1d61c6fdee   3 weeks ago   /bin/sh -c #(nop) CMD ["nginx" "-g" "daemon off;"] 0B 
    [root@ccx ~]#

*  编辑一个新的dockerfile文件  
    我们可以拷贝一份刚才的docker模版，然后编辑如下内容【注，CMD中的内容需要将空格改为`,`】，最后在当前目录新建一个`index.html`【名称固定的，里面的内容可以随便造一点】

[root@ccx ~]# cp Dockerfile Dockerfile_v2
    [root@ccx ~]# vim Dockerfile_v2 
    [root@ccx ~]# cat Dockerfile_v2
    FROM centos:v3
    MAINTAINER ccx
    
    RUN yum install nginx -y
    COPY index.html /usr/share/nginx/html
    EXPOSE 80
    
    CMD ["nginx","-g","daemon off;"]
    [root@ccx ~]# vim index.html 
    [root@ccx ~]# cat index.html 
    <p>
    hello word!
    </p>
    [root@ccx ~]#

*  编译镜像为nginx:v1  
    因为我们新增的一个dockerfile文件，所以我们需要用 -f 指定文件名  
    `docker build -t nginx:v1 . -f Dockerfile_v2`  
    过程如下【如果镜像中没有nginx源，会编译错误】

[root@ccx ~]# docker build -t nginx:v1 . -f Dockerfile_v2 
    Sending build context to Docker daemon  1.177GB
    Step 1/6 : FROM centos:v3
     ---> 0212a1a45667
    Step 2/6 : MAINTAINER ccx
     ---> Running in 3c6429284bf7
    Removing intermediate container 3c6429284bf7
     ---> 67508b852318
    Step 3/6 : RUN yum install nginx -y
     ---> Running in 59dff0944913
    Loaded plugins: fastestmirror, ovl
    Loading mirror speeds from cached hostfile
    Resolving Dependencies
    --> Running transaction check
    ---> Package nginx.x86_64 1:1.20.1-2.el7 will be installed
    --> Processing Dependency: nginx-filesystem = 1:1.20.1-2.el7 for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: libcrypto.so.1.1(OPENSSL_1_1_0)(64bit) for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: libssl.so.1.1(OPENSSL_1_1_0)(64bit) for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: libssl.so.1.1(OPENSSL_1_1_1)(64bit) for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: nginx-filesystem for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: openssl for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: redhat-indexhtml for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: system-logos for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: libcrypto.so.1.1()(64bit) for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: libprofiler.so.0()(64bit) for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Processing Dependency: libssl.so.1.1()(64bit) for package: 1:nginx-1.20.1-2.el7.x86_64
    --> Running transaction check
    ---> Package centos-indexhtml.noarch 0:7-9.el7.centos will be installed
    ---> Package centos-logos.noarch 0:70.0.6-3.el7.centos will be installed
    ---> Package gperftools-libs.x86_64 0:2.6.1-1.el7 will be installed
    ---> Package nginx-filesystem.noarch 1:1.20.1-2.el7 will be installed
    ---> Package openssl.x86_64 1:1.0.2k-21.el7_9 will be installed
    --> Processing Dependency: openssl-libs(x86-64) = 1:1.0.2k-21.el7_9 for package: 1:openssl-1.0.2k-21.el7_9.x86_64
    --> Processing Dependency: make for package: 1:openssl-1.0.2k-21.el7_9.x86_64
    --> Processing Dependency: libcrypto.so.10(OPENSSL_1.0.2)(64bit) for package: 1:openssl-1.0.2k-21.el7_9.x86_64
    ---> Package openssl11-libs.x86_64 1:1.1.1g-3.el7 will be installed
    --> Running transaction check
    ---> Package make.x86_64 1:3.82-24.el7 will be installed
    ---> Package openssl-libs.x86_64 1:1.0.1e-60.el7_3.1 will be updated
    ---> Package openssl-libs.x86_64 1:1.0.2k-21.el7_9 will be an update
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package               Arch        Version                   Repository    Size
    ================================================================================
    Installing:
     nginx                 x86_64      1:1.20.1-2.el7            epel         586 k
    Installing for dependencies:
     centos-indexhtml      noarch      7-9.el7.centos            base          92 k
     centos-logos          noarch      70.0.6-3.el7.centos       base          21 M
     gperftools-libs       x86_64      2.6.1-1.el7               base         272 k
     make                  x86_64      1:3.82-24.el7             base         421 k
     nginx-filesystem      noarch      1:1.20.1-2.el7            epel          23 k
     openssl               x86_64      1:1.0.2k-21.el7_9         updates      493 k
     openssl11-libs        x86_64      1:1.1.1g-3.el7            epel         1.5 M
    Updating for dependencies:
     openssl-libs          x86_64      1:1.0.2k-21.el7_9         updates      1.2 M
    
    Transaction Summary
    ================================================================================
    Install  1 Package  (+7 Dependent packages)
    Upgrade             ( 1 Dependent package)
    
    Total download size: 26 M
    Downloading packages:
    Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
    --------------------------------------------------------------------------------
    Total                                              4.9 MB/s |  26 MB  00:05     
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Installing : centos-logos-70.0.6-3.el7.centos.noarch                     1/10 
      Installing : centos-indexhtml-7-9.el7.centos.noarch                      2/10 
      Installing : 1:make-3.82-24.el7.x86_64                                   3/10 
      Installing : 1:nginx-filesystem-1.20.1-2.el7.noarch                      4/10 
      Installing : 1:openssl11-libs-1.1.1g-3.el7.x86_64                        5/10 
      Installing : gperftools-libs-2.6.1-1.el7.x86_64                          6/10 
      Updating   : 1:openssl-libs-1.0.2k-21.el7_9.x86_64                       7/10 
      Installing : 1:openssl-1.0.2k-21.el7_9.x86_64                            8/10 
      Installing : 1:nginx-1.20.1-2.el7.x86_64                                 9/10 
      Cleanup    : 1:openssl-libs-1.0.1e-60.el7_3.1.x86_64                    10/10 
      Verifying  : 1:nginx-1.20.1-2.el7.x86_64                                 1/10 
      Verifying  : 1:openssl-libs-1.0.2k-21.el7_9.x86_64                       2/10 
      Verifying  : gperftools-libs-2.6.1-1.el7.x86_64                          3/10 
      Verifying  : 1:openssl11-libs-1.1.1g-3.el7.x86_64                        4/10 
      Verifying  : 1:nginx-filesystem-1.20.1-2.el7.noarch                      5/10 
      Verifying  : 1:make-3.82-24.el7.x86_64                                   6/10 
      Verifying  : 1:openssl-1.0.2k-21.el7_9.x86_64                            7/10 
      Verifying  : centos-indexhtml-7-9.el7.centos.noarch                      8/10 
      Verifying  : centos-logos-70.0.6-3.el7.centos.noarch                     9/10 
      Verifying  : 1:openssl-libs-1.0.1e-60.el7_3.1.x86_64                    10/10 
    
    Installed:
      nginx.x86_64 1:1.20.1-2.el7                                                   
    
    Dependency Installed:
      centos-indexhtml.noarch 0:7-9.el7.centos                                      
      centos-logos.noarch 0:70.0.6-3.el7.centos                                     
      gperftools-libs.x86_64 0:2.6.1-1.el7                                          
      make.x86_64 1:3.82-24.el7                                                     
      nginx-filesystem.noarch 1:1.20.1-2.el7                                        
      openssl.x86_64 1:1.0.2k-21.el7_9                                              
      openssl11-libs.x86_64 1:1.1.1g-3.el7                                          
    
    Dependency Updated:
      openssl-libs.x86_64 1:1.0.2k-21.el7_9                                         
    
    Complete!
    Removing intermediate container 59dff0944913
     ---> f4aea8fab811
    Step 4/6 : COPY index.html /usr/share/nginx/html
     ---> 64f0b3c15c5e
    Step 5/6 : EXPOSE 80
     ---> Running in 00c9d88e2742
    Removing intermediate container 00c9d88e2742
     ---> 8b6bd0688188
    Step 6/6 : CMD ["nginx","-g","daemon off;"]
     ---> Running in 1b7e3750fa72
    Removing intermediate container 1b7e3750fa72
     ---> 13ee3750e1c8
    Successfully built 13ee3750e1c8
    Successfully tagged nginx:v1
    [root@ccx ~]#

*  通过查看镜像的全部内容，可以看到我们刚才定义的内容

[root@ccx ~]# docker images| grep nginx
    nginx                             v1        13ee3750e1c8   52 seconds ago      548MB
    nginx                             latest    d1a364dc548d   3 weeks ago         133MB
    [root@ccx ~]# docker history nginx:v1 
    IMAGE          CREATED              CREATED BY                                      SIZE      COMMENT
    13ee3750e1c8   About a minute ago   /bin/sh -c #(nop) CMD ["nginx" "-g" "daemon… 0B 
    8b6bd0688188   About a minute ago   /bin/sh -c #(nop) EXPOSE 80 0B 
    64f0b3c15c5e   About a minute ago   /bin/sh -c #(nop) COPY file:616c5da4cb1c7de2… 21B 
    f4aea8fab811   About a minute ago   /bin/sh -c yum install nginx -y                 191MB     
    67508b852318   About a minute ago   /bin/sh -c #(nop) MAINTAINER ccx 0B 
    0212a1a45667   30 minutes ago       /bin/sh -c #(nop) CMD ["/bin/bash"] 0B 
    2b86e5699766   30 minutes ago       /bin/sh -c yum install net-tools -y &&     y…   164MB     
    80fe76f4a233   30 minutes ago       /bin/sh -c #(nop) ADD file:9a052aed38285906d… 6.04kB 
    e74a3061df3a   30 minutes ago       /bin/sh -c rm -rf /etc/yum.repos.d/*            0B        
    cf8f1b1f7f64   About an hour ago    /bin/sh -c #(nop) MAINTAINER ccx 0B 
    328edcd84f1b   3 years ago          /bin/sh -c #(nop) CMD ["/bin/bash"] 0B 
    <missing>      3 years ago          /bin/sh -c #(nop) LABEL name=CentOS Base Im… 0B 
    <missing>      3 years ago          /bin/sh -c #(nop) ADD file:63492ba809361c51e… 193MB 
    [root@ccx ~]#

*  通过这个镜像创建一个容器，看是否正常

[root@ccx ~]# docker run -dit --name=web --restart=always -p 80:80 nginx:v1 
    b245ace740008e48cdbf5f62e57f38ca33bf7cbdef39d84606248b4d4a52a79e
    [root@ccx ~]# docker ps
    CONTAINER ID   IMAGE      COMMAND                  CREATED         STATUS         PORTS                               NAMES
    b245ace74000   nginx:v1   "nginx -g 'daemon of…"   3 seconds ago   Up 2 seconds   0.0.0.0:80->80/tcp, :::80->80/tcp   web
    [root@ccx ~]#

*  上面容器启动正常，可以看到本机端口80已经映射到容器的端口80了，那么现在使用浏览器，输入本机ip回车后页面是可以显示index中的内容的，成功。  
    ![在这里插入图片描述][2021061823543662.png]

## 编辑镜像文件【ENV指定变量】 ##

*  当使用 Dockerfile 进行构建镜像时，有时会需要设置容器内的环境变量。
 *  使用方法：`ENV <key>=<value> <key2>=<value2>`
 *  ENV 指令将环境变量 设置为值 。这个值将在构建阶段的所有后续指令的环境中， 也可以被替换使用在其他指令中。 该值将被解释为其他环境变量，因此如果引号字符没有转义，它们将被删除。像命令行解析一样，引号和反斜杠可以用于在值中包含空格。  
    例如：

ENV MY_NAME="super hero"
    ENV MY_CAT=fluffy

*  当使用生成的镜像运行容器时，使用 ENV 设置的环境变量将持久存在于容器内。 你可以使用 `docker inspect 容器名` 查看这些值，并使用 `docker run --env <key>=<value>`修改它们【也可以docker run的时候 -e 指定参数，这时候的参数会覆盖镜像中的参数】。
 *  dockerfile文件如下：我在新增容器的时候指定了变量a=123，然后我在创建容器的时候重新制定a=123\_now

[root@ccx ~]# cat dockerfile_v1 
    FROM hub.c.163.com/library/centos:latest
    MAINTAINER ccx_ssh_server
    ENV aa=123
    ENV bb=321
    
    RUN useradd ccx && \
        echo root | passwd --stdin root
    USER ccx
    
    VOLUME ["/ccx"]
    
    CMD ["/bin/bash"]
    [root@ccx ~]# 
    
    # 生成镜像
    [root@ccx ~]# docker build -t . -f dockerfile_v1 
    invalid argument "." for t: Error parsing reference: "." is not a valid repository/tag: invalid reference format
    See 'docker build --help'.
    [root@ccx ~]# 
    [root@ccx ~]# docker build -t centos:v1 . -f dockerfile_v1 
    Sending build context to Docker daemon 1.593 GB
    Step 1/8 : FROM hub.c.163.com/library/centos:latest
     ---> 328edcd84f1b
    Step 2/8 : MAINTAINER ccx_ssh_server
     ---> Using cache
     ---> 838371e7ae87
    Step 3/8 : ENV aa 123
     ---> Using cache
     ---> 9456dedc09b1
    Step 4/8 : ENV bb 321
     ---> Using cache
     ---> 6a86a8083e4b
    Step 5/8 : RUN useradd ccx &&     echo root | passwd --stdin root
     ---> Running in 35f2637de210
    
    Changing password for user root.
    passwd: all authentication tokens updated successfully.
     ---> 711018578e3f
    Removing intermediate container 35f2637de210
    Step 6/8 : USER ccx
     ---> Running in af9ed521a567
     ---> b81ad3f64b1d
    Removing intermediate container af9ed521a567
    Step 7/8 : VOLUME /ccx
     ---> Running in ac29ce706baa
     ---> ed2c8f47ca94
    Removing intermediate container ac29ce706baa
    Step 8/8 : CMD /bin/bash
     ---> Running in ac98417778c5
     ---> c85441b108da
    Removing intermediate container ac98417778c5
    Successfully built c85441b108da
    
    # 创建容器
    [root@ccx ~]# docker run -it --name=test --restart=always -e aa=123_now centos:v1 
    [ccx@de97fc9d16ab /]$ echo $aa
    123_now
    [ccx@de97fc9d16ab /]$ echo $bb
    321
    [ccx@de97fc9d16ab /]$

## 编辑镜像文件【USER指定用户】 ##

*  格式
    
     *  USER user
     *  USER user:group
     *  USER uid
     *  USER uid:gid
     *  USER user:gid
     *  USER uid:group
 *  示例  
    一般我们指定的用户，容器中是没有这个用户名的，所以我们指定用户名的时候，在USER前面加一个`RUN useradd user`创建这个用户，再指定。【也可以不用指定，我们创建好一个用户后，在生成容器的时候 `-u user`指定用户名】
 *  作用
    
     *  指定运行时的用户名或UID，后续的RUN也会使用指定的用户。
     *  当服务不需要管理权限时，可以通过该命令指定运行用户。并且可以在之前创建所需要的用户
 *  说明  
    要临时获取管理权限可以使用gosu，而不推荐sudo。
 *  注：  
    使用USER指定用户后，Dockerfile中其后的命令RUN、CMD、ENTRYPOINT都将使用该用户。镜像构建完成后，通过docker run运行容器时，可以通过-u参数来覆盖所指定的用户。
 *  dockerfile文件如下：我创建了一个用户ccx并指定ccx为默认用户

[root@ccx ~]# cat dockerfile_v1 
    FROM hub.c.163.com/library/centos:latest
    MAINTAINER ccx_ssh_server
    ENV aa=123
    ENV bb=321
    
    RUN useradd ccx && \
        echo root | passwd --stdin root
    USER ccx
    
    VOLUME ["/ccx"]
    
    CMD ["/bin/bash"]
    [root@ccx ~]# 
    
    # 生成镜像
    [root@ccx ~]# docker build -t . -f dockerfile_v1 
    invalid argument "." for t: Error parsing reference: "." is not a valid repository/tag: invalid reference format
    See 'docker build --help'.
    [root@ccx ~]# 
    [root@ccx ~]# docker build -t centos:v1 . -f dockerfile_v1 
    Sending build context to Docker daemon 1.593 GB
    Step 1/8 : FROM hub.c.163.com/library/centos:latest
     ---> 328edcd84f1b
    Step 2/8 : MAINTAINER ccx_ssh_server
     ---> Using cache
     ---> 838371e7ae87
    Step 3/8 : ENV aa 123
     ---> Using cache
     ---> 9456dedc09b1
    Step 4/8 : ENV bb 321
     ---> Using cache
     ---> 6a86a8083e4b
    Step 5/8 : RUN useradd ccx &&     echo root | passwd --stdin root
     ---> Running in 35f2637de210
    
    Changing password for user root.
    passwd: all authentication tokens updated successfully.
     ---> 711018578e3f
    Removing intermediate container 35f2637de210
    Step 6/8 : USER ccx
     ---> Running in af9ed521a567
     ---> b81ad3f64b1d
    Removing intermediate container af9ed521a567
    Step 7/8 : VOLUME /ccx
     ---> Running in ac29ce706baa
     ---> ed2c8f47ca94
    Removing intermediate container ac29ce706baa
    Step 8/8 : CMD /bin/bash
     ---> Running in ac98417778c5
     ---> c85441b108da
    Removing intermediate container ac98417778c5
    Successfully built c85441b108da
    
    # 创建容器
    [root@ccx ~]# docker run -it --name=test --restart=always centos:v1 
    [ccx@2000b48aba23 /]$ 
    [ccx@2000b48aba23 /]$ su - root
    Password: 
    [root@2000b48aba23 ~]#
    
    ## 容器中默认用户是ccx了，我们现在在创建容器的时候指定用户为root
    [root@ccx ~]# docker rm -f test 
    test
    [root@ccx ~]# docker run -it --name=test --restart=always -u root centos:v1 
    [root@ffbe157ebd26 /]# pwd
    /
    [root@ffbe157ebd26 /]# exit
    exit

## 编辑镜像文件【VOLUME 持久化目录】 ##

*  用于指定持久化目录 【下面的目录是容器中的存储目录，会对应在本机默认地址生成路径（下面有查看详细说明的），这种并不好，虽然数据会永久保留到本地，但数据不能共享，每当容器删除并新建后，ID变了，所以默认存储路径也就变了，还是手动创建时指定目录的好一些。】
 *  格式：  
    `VOLUME ["/path/to/dir"]`
 *  示例：  
    `VOLUME ["/data"]`  
    `VOLUME ["/var/www", "/var/log/apache2", "/etc/apache2"]`
 *  注：  
    一个卷可以存在于一个或多个容器的指定目录，该目录可以绕过联合文件系统，并具有以下功能：
    
     *  1 卷可以容器间共享和重用
     *  2 容器并不一定要和其它容器共享卷
     *  3 修改卷后会立即生效
     *  4 对卷的修改不会对镜像产生影响
     *  5 卷会一直存在，直到没有任何容器在使用它

[root@ccx ~]# docker run -it --name=test --restart=always centos:v1 
    [ccx@8c8b1dc9b380 /]$ su - 
    Password: 
    [root@8c8b1dc9b380 ~]# cd /ccx/
    [root@8c8b1dc9b380 ccx]# ls
    [root@8c8b1dc9b380 ccx]# touch ccxhero
    [root@8c8b1dc9b380 ccx]# ls
    ccxhero
    [root@8c8b1dc9b380 ccx]# exit
    logout
    [ccx@8c8b1dc9b380 /]$ 
    [ccx@8c8b1dc9b380 /]$ exit
    exit
    [root@ccx ~]# docker inspect test |egrep -B 1 volume
                { 
                    "Type": "volume",
                    "Name": "4bcec9409e950425ab4a39974a1a91690360a53bf4952c0cbd629a617ef84734",
                    "Source": "/var/lib/docker/volumes/4bcec9409e950425ab4a39974a1a91690360a53bf4952c0cbd629a617ef84734/_data",
    [root@ccx ~]# ls /var/lib/docker/volumes/4bcec9409e950425ab4a39974a1a91690360a53bf4952c0cbd629a617ef84734/_data/
    ccxhero
    [root@ccx ~]#

# 搭建一个ssh服务器 #

*  需要准备一个镜像，我用的是网易云的默认centos镜像。
 *  在任意位置编辑一个`dockerfile`文件，里面写ssh服务器的必备组件。  
    思路：搭建一个服务器最基本的，就是分多次搭建，后面启动报错以后，查看日志，日志报什么错就添加什么功能就行了，如下面的文件中，文件key和修改的文件日志中都会有报错提示的。  
    注，多次编译的话，每次编译后都需要删除本地文件`.ssh/known_hosts`中的容器ip信息【因为每次修改容器key都会改变，所以会ssh报错】

## dockerfile文件内容和编译过程如下 ##

[root@ccx ~]# cat dockerfile 
    FROM hub.c.163.com/library/centos:latest
    MAINTAINER ccx_ssh_server
    RUN yum install openssh-server openssh-clients -y && \
        ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key && \
        ssh-keygen -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key && \
        ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_ky && \
        echo root | passwd --stdin root && \
        sed -i '/UseDNS/cUseDNS no' /etc/ssh/sshd_config
    
    EXPOSE 22
    CMD ["/usr/sbin/sshd","-D"]
    [root@ccx ~]# 
    [root@ccx ~]# docker build -t centos:ssh .
    Sending build context to Docker daemon 1.593 GB
    Step 1/5 : FROM hub.c.163.com/library/centos:latest
     ---> 328edcd84f1b
    Step 2/5 : MAINTAINER ccx_ssh_server
     ---> Using cache
     ---> 838371e7ae87
    Step 3/5 : RUN yum install openssh-server openssh-clients -y &&     ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key &&     ssh-keygen -t ecdsa -f /etc/ssh/ssh_host_ecdsa_key &&     ssh-keygen -t ed25519 -f /etc/ssh/ssh_host_ed25519_ky &&     echo root | passwd --stdin root &&     sed -i '/UseDNS/cUseDNS no' /etc/ssh/sshd_config
     ---> Running in 1e9a85cf5eb9
    
    Loaded plugins: fastestmirror, ovl
    Determining fastest mirrors
     * base: mirrors.aliyun.com
     * extras: mirrors.aliyun.com
     * updates: mirrors.aliyun.com
    Resolving Dependencies
    --> Running transaction check
    ---> Package openssh-clients.x86_64 0:7.4p1-21.el7 will be installed
    --> Processing Dependency: openssh = 7.4p1-21.el7 for package: openssh-clients-7.4p1-21.el7.x86_64
    --> Processing Dependency: fipscheck-lib(x86-64) >= 1.3.0 for package: openssh-clients-7.4p1-21.el7.x86_64
    --> Processing Dependency: libcrypto.so.10(OPENSSL_1.0.2)(64bit) for package: openssh-clients-7.4p1-21.el7.x86_64
    --> Processing Dependency: libfipscheck.so.1()(64bit) for package: openssh-clients-7.4p1-21.el7.x86_64
    --> Processing Dependency: libedit.so.0()(64bit) for package: openssh-clients-7.4p1-21.el7.x86_64
    ---> Package openssh-server.x86_64 0:7.4p1-21.el7 will be installed
    --> Processing Dependency: libwrap.so.0()(64bit) for package: openssh-server-7.4p1-21.el7.x86_64
    --> Running transaction check
    ---> Package fipscheck-lib.x86_64 0:1.4.1-6.el7 will be installed
    --> Processing Dependency: /usr/bin/fipscheck for package: fipscheck-lib-1.4.1-6.el7.x86_64
    ---> Package libedit.x86_64 0:3.0-12.20121213cvs.el7 will be installed
    ---> Package openssh.x86_64 0:7.4p1-21.el7 will be installed
    ---> Package openssl-libs.x86_64 1:1.0.1e-60.el7_3.1 will be updated
    ---> Package openssl-libs.x86_64 1:1.0.2k-21.el7_9 will be an update
    ---> Package tcp_wrappers-libs.x86_64 0:7.6-77.el7 will be installed
    --> Running transaction check
    ---> Package fipscheck.x86_64 0:1.4.1-6.el7 will be installed
    --> Finished Dependency Resolution
    
    Dependencies Resolved
    
    ================================================================================
     Package               Arch       Version                     Repository   Size
    ================================================================================
    Installing:
     openssh-clients       x86_64     7.4p1-21.el7                base        655 k
     openssh-server        x86_64     7.4p1-21.el7                base        459 k
    Installing for dependencies:
     fipscheck             x86_64     1.4.1-6.el7                 base         21 k
     fipscheck-lib         x86_64     1.4.1-6.el7                 base         11 k
     libedit               x86_64     3.0-12.20121213cvs.el7      base         92 k
     openssh               x86_64     7.4p1-21.el7                base        510 k
     tcp_wrappers-libs     x86_64     7.6-77.el7                  base         66 k
    Updating for dependencies:
     openssl-libs          x86_64     1:1.0.2k-21.el7_9           updates     1.2 M
    
    Transaction Summary
    ================================================================================
    Install  2 Packages (+5 Dependent packages)
    Upgrade             ( 1 Dependent package)
    
    Total download size: 3.0 M
    Downloading packages:
    Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
    warning: /var/cache/yum/x86_64/7/base/packages/fipscheck-lib-1.4.1-6.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY
    Public key for fipscheck-lib-1.4.1-6.el7.x86_64.rpm is not installed
    Public key for openssl-libs-1.0.2k-21.el7_9.x86_64.rpm is not installed
    --------------------------------------------------------------------------------
    Total                                              603 kB/s | 3.0 MB  00:05     
    Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    Importing 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-7-3.1611.el7.centos.x86_64 (@CentOS)
     From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
    Running transaction check
    Running transaction test
    Transaction test succeeded
    Running transaction
      Updating   : 1:openssl-libs-1.0.2k-21.el7_9.x86_64                        1/9 
      Installing : fipscheck-1.4.1-6.el7.x86_64                                 2/9 
      Installing : fipscheck-lib-1.4.1-6.el7.x86_64                             3/9 
      Installing : openssh-7.4p1-21.el7.x86_64                                  4/9 
      Installing : tcp_wrappers-libs-7.6-77.el7.x86_64                          5/9 
      Installing : libedit-3.0-12.20121213cvs.el7.x86_64                        6/9 
      Installing : openssh-clients-7.4p1-21.el7.x86_64                          7/9 
      Installing : openssh-server-7.4p1-21.el7.x86_64                           8/9 
      Cleanup    : 1:openssl-libs-1.0.1e-60.el7_3.1.x86_64                      9/9 
      Verifying  : fipscheck-lib-1.4.1-6.el7.x86_64                             1/9 
      Verifying  : openssh-7.4p1-21.el7.x86_64                                  2/9 
      Verifying  : fipscheck-1.4.1-6.el7.x86_64                                 3/9 
      Verifying  : openssh-clients-7.4p1-21.el7.x86_64                          4/9 
      Verifying  : libedit-3.0-12.20121213cvs.el7.x86_64                        5/9 
      Verifying  : tcp_wrappers-libs-7.6-77.el7.x86_64                          6/9 
      Verifying  : 1:openssl-libs-1.0.2k-21.el7_9.x86_64                        7/9 
      Verifying  : openssh-server-7.4p1-21.el7.x86_64                           8/9 
      Verifying  : 1:openssl-libs-1.0.1e-60.el7_3.1.x86_64                      9/9 
    
    Installed:
      openssh-clients.x86_64 0:7.4p1-21.el7   openssh-server.x86_64 0:7.4p1-21.el7  
    
    Dependency Installed:
      fipscheck.x86_64 0:1.4.1-6.el7            fipscheck-lib.x86_64 0:1.4.1-6.el7  
      libedit.x86_64 0:3.0-12.20121213cvs.el7   openssh.x86_64 0:7.4p1-21.el7       
      tcp_wrappers-libs.x86_64 0:7.6-77.el7    
    
    Dependency Updated:
      openssl-libs.x86_64 1:1.0.2k-21.el7_9                                         
    
    Complete!
    Enter passphrase (empty for no passphrase): Enter same passphrase again: Generating public/private rsa key pair.
    Your identification has been saved in /etc/ssh/ssh_host_rsa_key.
    Your public key has been saved in /etc/ssh/ssh_host_rsa_key.pub.
    The key fingerprint is:
    SHA256:WSZdXGlHGIi3fCei6smn6VuynOun+fGEjBSLTVYjeZc root@c7947be2eb9d
    The key's randomart image is: +---[RSA 2048]----+ | ..oo.+o=.| | .+ooE + .| | =.++ o . | | = B + o .| | . S . o o | | . o.. | | o.= . | | o.Oo+ | | +^O. . | +----[SHA256]-----+ Enter passphrase (empty for no passphrase): Enter same passphrase again: Generating public/private ecdsa key pair. Your identification has been saved in /etc/ssh/ssh_host_ecdsa_key. Your public key has been saved in /etc/ssh/ssh_host_ecdsa_key.pub. The key fingerprint is: SHA256:H89DqtJMeBqw4r/cVKWsEDnDSIo5isgyeO2D4UVA41A root@c7947be2eb9d The key's randomart image is:
    +---[ECDSA 256]---+
    |.oE              |
    |.* = .           |
    |= o B     .      |
    |*. o.+ . o       |
    |B.o +o .S . .    |
    |.+.=..ooo. *     |
    | .o.o oB  o +    |
    |  .. +o o.   .   |
    |   .+....        |
    +----[SHA256]-----+
    Enter passphrase (empty for no passphrase): Enter same passphrase again: Generating public/private ed25519 key pair.
    Your identification has been saved in /etc/ssh/ssh_host_ed25519_ky.
    Your public key has been saved in /etc/ssh/ssh_host_ed25519_ky.pub.
    The key fingerprint is:
    SHA256:tNvw7NqAuYlQluoxicpM0cGhcydbAENyWiOEApoIlo0 root@c7947be2eb9d
    The key's randomart image is:
    +--[ED25519 256]--+
    |X*Oo             |
    |OE+oo            |
    |*o = o  .        |
    |  + *. . .       |
    | . o+   S        |
    | ..=   o *       |
    |..*   o o +      |
    |=. + . o +       |
    |.o. . o ..o      |
    +----[SHA256]-----+
    Changing password for user root.
    passwd: all authentication tokens updated successfully.
     ---> 1f5218f8c394
    Removing intermediate container 1e9a85cf5eb9
    Step 4/5 : EXPOSE 22
     ---> Running in 48cc84e52301
     ---> 7adefc98f42a
    Removing intermediate container 48cc84e52301
    Step 5/5 : CMD /usr/sbin/sshd -D
     ---> Running in 4753b5a05b20
     ---> 74245a4c3090
    Removing intermediate container 4753b5a05b20
    Successfully built 74245a4c3090
    [root@ccx ~]# 
    [root@ccx ~]# docker images | ssh
    usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]
               [-D [bind_address:]port] [-E log_file] [-e escape_char]
               [-F configfile] [-I pkcs11] [-i identity_file]
               [-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec]
               [-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address]
               [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]]
               [user@]hostname [command]
    [root@ccx ~]# docker images | grep ssh
    centos                            ssh                 74245a4c3090        15 seconds ago      319 MB
    [root@ccx ~]#

## 创建容器使用测试 ##

[root@ccx ~]# docker run -dit --restart=always --name=ssh centos:ssh 
    3c988c5bfffb9c452502aedd8af66913ed8f25daf2a942321a369a178616b82e
    [root@ccx ~]# docker ps
    CONTAINER ID        IMAGE                             COMMAND                  CREATED             STATUS              PORTS                NAMES
    3c988c5bfffb        centos:ssh                        "/usr/sbin/sshd -D"      10 seconds ago      Up 9 seconds        22/tcp               ssh
    [root@ccx ~]# docker inspect ssh | grep IPA
                "SecondaryIPAddresses": null,
                "IPAddress": "172.17.0.4",
                        "IPAMConfig": null,
                        "IPAddress": "172.17.0.4",
    [root@ccx ~]# ssh 172.17.0.4
    The authenticity of host '172.17.0.4 (172.17.0.4)' can't be established. ECDSA key fingerprint is SHA256:H89DqtJMeBqw4r/cVKWsEDnDSIo5isgyeO2D4UVA41A. ECDSA key fingerprint is MD5:c5:6e:c3:88:f8:a8:3a:f7:e5:d2:f5:ed:9d:f4:ac:6f. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '172.17.0.4' (ECDSA) to the list of known hosts. root@172.17.0.4's password: 
    [root@3c988c5bfffb ~]# 
    [root@3c988c5bfffb ~]# 
    [root@3c988c5bfffb ~]# pwd
    /root
    [root@3c988c5bfffb ~]# exit
    logout
    Connection to 172.17.0.4 closed.
    [root@ccx ~]#

*  查看sshcmd方法如下：

[root@ccx ~]# ps aux | grep -v grep | grep ssh
    root       9735  0.0  0.0 112756  4308 ?        Ss   09:05   0:00 /usr/sbin/sshd -D
    root      21042  0.1  0.1 163448  6192 ?        Ss   09:32   0:10 sshd: root@pts/2,pts/3
    [root@ccx ~]#

[2021061823543662.png]: /images/20221005/64f355f9e3b74fbaacad856cc7888b09.png