Dockerfile 是一个文本格式的配置文件， 可以使用Dockerfile 来快速创建自定义的镜像。Dockerfile有典型的基本结构及其支持的众多指令，具体可以参照Docker技术入门与实践，这篇博客(Docker基础-使用Dockerfile创建镜像)整理了出来，也可以拿来参考。这里主要总结为镜像添加SSH服务 。
一些进入容器的办法， 比如用attach 、exec 等命令，但是这些命令都无法解决远程管理容器的问题。因此，当需要远程登录到容器内进行一些操作的时候，就需要SSH 的支持。介绍如何自行创建一个带有SSH 服务的镜像，并介绍两种创建容器的方法：基于docker commit 命令创建和基于Dockerfile 创建。
1 基于docker commit命令创建
1.1 获取镜像并创建一个容器
root@slave1:/home/xxx/Documents# docker pull ubuntu:16.04
16.04: Pulling from library/ubuntu
Digest: sha256:97b54e5692c27072234ff958a7442dde4266af21e7b688e7fca5dc5acc8ed7d9
Status: Image is up to date for ubuntu:16.04
root@slave1:/home/xxx/Documents# docker run -it ubuntu:16.04 bash
root@185a722ee292:/#
1.2 配置软件源
检查软件源，并使用apt-get update 命令来更新软件源信息：
root@185a722ee292:/# apt-get update
Get:1 http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [109 kB]
Get:3 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages [940 kB]
Get:4 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
Get:5 http://archive.ubuntu.com/ubuntu xenial-backports InRelease [107 kB]
Get:6 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages [1558 kB]
Get:7 http://security.ubuntu.com/ubuntu xenial-security/restricted amd64 Packages [12.7 kB]
Get:8 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 Packages [582 kB]
Get:9 http://security.ubuntu.com/ubuntu xenial-security/multiverse amd64 Packages [6114 B]
Get:10 http://archive.ubuntu.com/ubuntu xenial/restricted amd64 Packages [14.1 kB]
Get:11 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages [9827 kB]
Get:12 http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages [176 kB]
Get:13 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [1322 kB]
Get:14 http://archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 Packages [13.1 kB]
Get:15 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [986 kB]
Get:16 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages [19.1 kB]
Get:17 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages [7942 B]
Get:18 http://archive.ubuntu.com/ubuntu xenial-backports/universe amd64 Packages [8807 B]
Fetched 16.0 MB in 1min 39s (161 kB/s)
Reading package lists... Done
1.3 安装和配置SSH服务
更新软件包缓存后可以安装SSH 服务了，选择主流的opens sh-server 作为服务端
root@185a722ee292:/# apt-get install openssh-server
如果需要正常启动SSH 服务， 则目录/var/run/sshd 必须存在。下面手动创建它，并启动SSH 服务：
root@185a722ee292:/# mkdir -p /var/run/sshd
root@185a722ee292:/# /usr/sbin/sshd -D &
[1] 3243
查看容器的22 端口（ SSH 服务默认监昕的端口），可见此端口已经处于监听状态：
root@185a722ee292:/# netstat -tunlp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 3243/sshd
tcp6 0 0 :::22 :::* LISTEN 3243/sshd
如果bash: vi: command not found 用apt-get install net-tools安装net工具包：
修改SSH服务的安全登录配置，取消pam登陆限制
root@185a722ee292:/# sed -ri 's/session required pam_loginuid.so/#session required pam_loginuid.so/g' /etc/pam.d/sshd
在root 用户目录下创建.ssh 目录，并复制需要登录的公钥信息（一般为本地主机用户目录下的.ssh/id_rsa.pub 文件，可由ssh-keygen -t rsa 命令生成）到authorized_keys 文件中：
root@185a722ee292:/# mkdir root/.ssh
root@185a722ee292:/# vi /root/.ssh/authorized_keys
bash: vi: command not found
root@185a722ee292:/# apt-get install vim
root@185a722ee292:/# vi /root/.ssh/authorized_keys
创建自动启动SSH 服务的可执行文件run . sh ，并添加可执行权限：
root@185a722ee292:/# vi /run.sh
root@185a722ee292:/# chmod +x run.sh
root@185a722ee292:/#
root@185a722ee292:/# exit
exit
run.sh 脚本内容如下：
#!/bin/bash
/usr/sbin/sshd -D
1.4 保存镜像
将退出的容器用docker commit命令保存为一个新的sshd:ubuntu镜像：
root@slave1:/home/xxx/Documents# docker commit 185a722ee292 sshd:ubuntu
sha256:4a1f2846a21fee31106ec6d86ad9ea8cc96295f59ca7a533a8d5195446cebcae
使用docker images 查看本地生成的新镜像sshd:ubuntu ，目前拥有的镜像如下：
root@slave1:/home/xxx/Documents# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
sshd ubuntu 4a1f2846a21f About a minute ago 235MB
1.5 使用镜像
启动容器，并添加端口映射10022 >22 。其中100 22 是宿主主机的端口， 22 是容器的SSH 服务监昕端口：
root@slave1:/home/xxx/Documents# docker run -p 10022:22 -d sshd:ubuntu /run.sh
cdedf8932122f63b6165c744e9e10c1a453b19986332c6f6f5a84a6c61ab1bbe
启动成功后，可以在宿主主机上看到容器运行的详细信息。
root@slave1:/home/xxx/Documents# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cdedf8932122 sshd:ubuntu "/run.sh" 23 seconds ago Up 21 seconds 0.0.0.0:10022->22/tcp youthful_wing
在宿主主机（ 192.168.220.128 ）或其他主机上，可以通过SSH 访问10022 端口来登录容器：
root@slave1:/home/xxx/Documents# ssh 192.168.220.128 -p 10022
The authenticity of host '[192.168.220.128]:10022 ([192.168.220.128]:10022)' can't be established.
ECDSA key fingerprint is SHA256:PIe3rPCEmGvRA/zljQcz8OZzELeZvWnDtd2CXkqmfSk.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[192.168.220.128]:10022' (ECDSA) to the list of known hosts.
Welcome to Ubuntu 16.04 LTS (GNU/Linux 4.4.0-98-generic x86_64)
* Documentation: https://help.ubuntu.com/
The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.
2 基于Dockerfile 创建
使用Dockerfile 来创建一个支持SSH 服务的镜像。
2.1 创建工作目录
创建一个sshd_ubuntu 工作目录：
root@slave1:/home/xxx/Documents# mkdir sshd_ubuntu
root@slave1:/home/xxx/Documents# ls
sshd_ubuntu
创建Dockerfile 和run.sh 文件：
root@slave1:/home/xxx/Documents# cd sshd_ubuntu
root@slave1:/home/xxx/Documents/sshd_ubuntu# touch Dockerfile run.sh
root@slave1:/home/xxx/Documents/sshd_ubuntu# ls
Dockerfile run.sh
2.2 编写run.sh脚本和authorized_keys文件 vi run.sh
#!/bin/bash
/usr/sbin/sshd -D
root@slave1:/home/xxx/Documents/sshd_ubuntu# ssh-keygen -t rsa
root@slave1:/home/xxx/Documents/sshd_ubuntu# cat ~/.ssh/id_rsa.pub >authorized_keys
2.3 编写Dockerfile
root@slave1:/home/xxx/Documents/sshd_ubuntu# vi Dockerfile
# 基础镜像信息
FROM ubuntu:16.04
# 维护者信息
MAINTAINER zzz xxxxxxxx@qq.com
# 更新apt缓存、安装ssh服务
RUN apt-get update && apt-get install -y openssh-server
RUN mkdir -p /var/run/sshd
RUN mkdir -p /root/.ssh
#取消pam限制
RUN sed -ri 's/session requireD pam_loginuid.so/#session required pam_loginuid.so/g' /etc/pam.d/sshd
# 配置免密和自启动脚本
ADD authorized_keys /root/.ssh/authorized_keys
ADD run.sh /run.sh
RUN chmod 755 /run.sh
# 开放22端口
EXPOSE 22
# 设置脚本自启动
CMD ["/run.sh"]
2.4 创建镜像
在sshd_ubuntu 目录下，使用docker build 命令来创建镜像。表示使用当前目录中的Dockerfile
root@slave1:/home/xxx/Documents# cd sshd_ubuntu
root@slave1:/home/xxx/Documents/sshd_ubuntu# docker build -t sshd:dockerfile .
Sending build context to Docker daemon 4.608kB
Step 1/11 : FROM ubuntu:16.04
---> 5e13f8dd4c1a
Step 2/11 : MAINTAINER zzz 473612131@qq.com
---> Using cache
---> 0748b6027d39
Step 3/11 : RUN apt-get update && apt-get install -y openssh-server
---> Using cache
---> a251326511ad
Step 4/11 : RUN mkdir -p /var/run/sshd
---> Using cache
---> 7f7223f9ca3f
Step 5/11 : RUN mkdir -p /root/.ssh
---> Using cache
---> ef9f018d909c
Step 6/11 : RUN sed -ri 's/session requireD pam_loginuid.so/#session required pam_loginuid.so/g' /etc/pam.d/sshd
---> Running in 94c11b0c54ec
Removing intermediate container 94c11b0c54ec
---> cea047a4b34f
Step 7/11 : ADD authorized_keys /root/.ssh/authorized_keys
---> 8312e768de97
Step 8/11 : ADD run.sh /run.sh
---> f5c23bd379b2
Step 9/11 : RUN chmod 755 /run.sh
---> Running in 8f95705b05b4
Removing intermediate container 8f95705b05b4
---> 03eb32be673e
Step 10/11 : EXPOSE 22
---> Running in ef4439caf998
Removing intermediate container ef4439caf998
---> 3ac6903206c9
Step 11/11 : CMD ["/run.sh"]
---> Running in 8271fe311161
Removing intermediate container 8271fe311161
---> 10ba2747ab4a
Successfully built 10ba2747ab4a
Successfully tagged sshd:dockerfile
root@slave1:/home/xxx/Documents/sshd_ubuntu# docker images #本地查看sshd :dockerfile 镜像己存在
REPOSITORY TAG IMAGE ID CREATED SIZE
sshd dockerfile 10ba2747ab4a 2 minutes ago 200MB
2.5 测试镜像，运行容器
使用刚才创建的sshd:dockerfile 镜像来运行一个容器。直接启动镜像，映射容器的22 端口到本地的10122 端口：
root@slave1:/home/xxx/Documents/sshd_ubuntu# docker run -d -p 10122:22 sshd:dockerfile
7cd646779554e185a34d0f775ad8bb81cef4af8547df5ba7ac79d8eed0571d48
root@slave1:/home/xxx/Documents/sshd_ubuntu# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
7cd646779554 sshd:dockerfile "/run.sh" 40 seconds ago Up 39 seconds 0.0.0.0:10122->22/tcp loving_pike
在宿主主机新打开一个终端，连接到新建的容器：
root@slave1:/home/xxx/Documents/sshd_ubuntu# ssh 192.168.220.128 -p 10122
The authenticity of host '[192.168.220.128]:10122 ([192.168.220.128]:10122)' can't be established.
ECDSA key fingerprint is SHA256:MTblEFxBW0AGUzlvSzc5ouq1xM01jcykUFCzwW91Khc.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[192.168.220.128]:10122' (ECDSA) to the list of known hosts.
Welcome to Ubuntu 16.04.6 LTS (GNU/Linux 4.10.0-28-generic x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage
The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.
root@7cd646779554:~#
***参考：
Docker技术入门与实战链接：https://pan.baidu.com/s/1r_TfonbXxPk6ogKvNxGp3g
提取码：c5i2