创建文件夹

首先，创建一个叫做 sshd_ubuntu 的文件夹，用于存放我们的 Dockerfile 、脚本文件、以及其他文件。

$ mkdir sshd_ubuntu
$ ls
sshd_ubuntu
$ cd sshd_ubuntu/
$ touch Dockerfile run.sh
$ ls
Dockerfile  run.sh

编写 shell 脚本和 authorized_keys 文件

其中脚本文件 run.sh 的内容与上一小节一致

#!/bin/bash
/usr/sbin/sshd -D

创建 authorized_keys 文件

$ ssh-keygen
#根据提示生成访问密钥
$ cat ~/.ssh/id_rsa.pub >authorized_keys
#复制公钥到 authorized_keys 文件中

下面是 Dockerfile 的内容及解释

#设置继承镜像
FROM ubuntu:14.04
#提供一些作者的信息
MAINTAINER dwj_zz@163.com
#下面开始运行命令,此处更改ubuntu的源为国内163的源
RUN echo "deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse" > /etc/apt/sources.list
RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse" >> /etc/apt/sources.list
RUN apt-get update

#安装 ssh 服务
RUN 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

#复制配置文件到相应位置,并赋予脚本可执行权限
ADD authorized_keys /root/.ssh/authorized_keys
ADD run.sh /run.sh
RUN chmod 755 /run.sh

#开放端口
EXPOSE 22

#设置自启动命令
CMD ["/run.sh"]

创建镜像

$ sudo docker build -t sshd:dockerfile .
Sending build context to Docker daemon 5.632 kB
Sending build context to Docker daemon
Step 0 : FROM ubuntu:14.04
^Z
[1]+  Stopped                 sudo docker build -t sshd:dockerfile .
#这里我发现创建的速度好慢，于是暂停创建过程，先查看下本地 images
$ sudo docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
sshd                ubuntu              7aef2cd95fd0        12 hours ago        255.2 MB
busybox             latest              e72ac664f4f0        3 weeks ago         2.433 MB
ubuntu              latest              ba5877dc9bec        3 months ago        192.7 MB
#原来我们的 ubuntu 镜像是使用默认的 latest 标签，而我们在 Dockerfile 中一般都是指定版本标签。
$ sudo docker tag ba5 ubuntu:14.04
$ pwd
/home/xxx/sshd_ubuntu
$ sudo docker build -t sshd:dockerfile .
#这里注意一下，在最后还有一个 “.” ，表示使用当前目录的 Dockerfile
Sending build context to Docker daemon 5.632 kB
Sending build context to Docker daemon
Step 0 : FROM ubuntu:14.04
 ---> ba5877dc9bec
Step 1 : MAINTAINER dwj_zz@163.com
 ---> Running in 188d74d02d35
 ---> 473eb019b331
Removing intermediate container 188d74d02d35
#使用 Dockerfile 创建，他会帮你删除中间无用的文件层
Step 2 : RUN echo "deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse" > /etc/apt/sources.list
 ---> Running in f52e2a583db5
 ---> bd4ceef2ee19
Removing intermediate container f52e2a583db5
Step 3 : RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse" >> /etc/apt/sources.list
 ---> Running in 897d65dfe9be
 ---> 9cd736f11928
Removing intermediate container 897d65dfe9be
Step 4 : RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse" >> /etc/apt/sources.list
 ---> Running in ec3433db813e
 ---> 3fca0b605de4
Removing intermediate container ec3433db813e
Step 5 : RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse" >> /etc/apt/sources.list
 ---> Running in 4a0fe165598f
 ---> f6d1c7af36c8
Removing intermediate container 4a0fe165598f
Step 6 : RUN echo "deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse" >> /etc/apt/sources.list
 ---> Running in 209179c21053
 ---> 0cda758c9f3c
Removing intermediate container 209179c21053
Step 7 : RUN apt-get update
 ---> Running in 1fd40eb66f7b
Ign http://archive.ubuntu.com trusty-proposed InRelease
Get:1 http://archive.ubuntu.com trusty-proposed Release.gpg [933 B]
Get:2 http://archive.ubuntu.com trusty-proposed Release [110 kB]
Get:3 http://archive.ubuntu.com trusty-proposed/main amd64 Packages [160 kB]
...
#为了节约篇幅，删去一些无关紧要的内容
Fetched 11.3 MB in 1min 37s (116 kB/s)
Reading package lists...
 ---> 0f132591eddc
Removing intermediate container 1fd40eb66f7b
Step 8 : RUN apt-get install -y openssh-server
 ---> Running in 399e4ea726d2
Reading package lists...
Building dependency tree...
Reading state information...
The following extra packages will be installed:
  ca-certificates krb5-locales libck-connector0 libedit2 libgssapi-krb5-2
  libidn11 libk5crypto3 libkeyutils1 libkrb5-3 libkrb5support0
  libpython-stdlib libpython2.7-minimal libpython2.7-stdlib libwrap0 libx11-6
  libx11-data libxau6 libxcb1 libxdmcp6 libxext6 libxmuu1 ncurses-term
  openssh-client openssh-sftp-server openssl python python-chardet
  python-minimal python-requests python-six python-urllib3 python2.7
  python2.7-minimal ssh-import-id tcpd wget xauth
Suggested packages:
  krb5-doc krb5-user ssh-askpass libpam-ssh keychain monkeysphere rssh
  molly-guard ufw python-doc python-tk python2.7-doc binutils binfmt-support
The following NEW packages will be installed:
  ca-certificates krb5-locales libck-connector0 libedit2 libgssapi-krb5-2
  libidn11 libk5crypto3 libkeyutils1 libkrb5-3 libkrb5support0
  libpython-stdlib libpython2.7-minimal libpython2.7-stdlib libwrap0 libx11-6
  libx11-data libxau6 libxcb1 libxdmcp6 libxext6 libxmuu1 ncurses-term
  openssh-client openssh-server openssh-sftp-server openssl python
  python-chardet python-minimal python-requests python-six python-urllib3
  python2.7 python2.7-minimal ssh-import-id tcpd wget xauth
0 upgraded, 38 newly installed, 0 to remove and 29 not upgraded.
Need to get 7599 kB of archives.
After this operation, 35.3 MB of additional disk space will be used.
Get:1 http://mirrors.163.com/ubuntu/ trusty/main libedit2 amd64 3.1-20130712-2 [86.7 kB]
...
Running hooks in /etc/ca-certificates/update.d....done.
Processing triggers for ureadahead (0.100.0-16) ...
 ---> 62f952643e33
Removing intermediate container 399e4ea726d2
Step 9 : RUN mkdir -p /var/run/sshd
 ---> Running in aa1c4d469284
 ---> e81557dd4887
Removing intermediate container aa1c4d469284
Step 10 : RUN mkdir -p /root/.ssh
 ---> Running in 0626987081d0
 ---> 23882ee06756
Removing intermediate container 0626987081d0
Step 11 : RUN sed -ri ‘s/session    required     pam_loginuid.so/#session    required     pam_loginuid.so/g‘ /etc/pam.d/sshd
 ---> Running in 3808c650bf85
 ---> 6c0ca1d20d7f
Removing intermediate container 3808c650bf85
Step 12 : ADD authorized_keys /root/.ssh/authorized_keys
 ---> a64bbd8ae617
Removing intermediate container 16e2d93d6ef0
Step 13 : ADD run.sh /run.sh
 ---> 230711022f7d
Removing intermediate container 137e56188d7b
Step 14 : RUN chmod 755 /run.sh
 ---> Running in a876e4ea378e
 ---> 32d74bbb7406
Removing intermediate container a876e4ea378e
Step 15 : EXPOSE 22
 ---> Running in eeaf9352ca11
 ---> 901e3fa9f596
Removing intermediate container eeaf9352ca11
Step 16 : CMD /run.sh
 ---> Running in 48c37db83ffb
 ---> 570c26a9de68
Removing intermediate container 48c37db83ffb
Successfully built 570c26a9de68
#最后，返回告诉我们创建成功，镜像 id 号是570c26a9de68，让我们来查看下
$ sudo docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
sshd                dockerfile          570c26a9de68        4 minutes ago       246.5 MB
sshd                ubuntu              7aef2cd95fd0        12 hours ago        255.2 MB
busybox             latest              e72ac664f4f0        3 weeks ago         2.433 MB
ubuntu              14.04               ba5877dc9bec        3 months ago        192.7 MB
ubuntu              latest              ba5877dc9bec        3 months ago        192.7 MB

测试镜像，运行容器

我们使用刚才我们创建的 sshd:dockerfile 来运行一个容器，看看时候达到我们的要求。

$ sudo docker ps
#这是上一小节，我们用 ”commit“ 方式建立的容器
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                 NAMES
3ad7182aa47f        sshd:ubuntu         "/run.sh"           12 hours ago        Up 3 seconds        0.0.0.0:100->22/tcp   focused_ptolemy
$ sudo docker run -d -p 101:22 sshd:dockerfile
#注意到，跟上一小节运行的容器的命令不一样，不需要在输入命令‘/run.sh’了，因为已经在 Dockerfile 中定义了自启动命令。
890c04ff8d769b604386ba4475253ae8c21fc92d60083759afa77573bf4e8af1
$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                 NAMES
890c04ff8d76        sshd:dockerfile     "/run.sh"           4 seconds ago       Up 3 seconds        0.0.0.0:101->22/tcp   high_albattani
3ad7182aa47f        sshd:ubuntu         "/run.sh"           12 hours ago        Up 28 seconds       0.0.0.0:100->22/tcp   focused_ptolemy

在本地新开一个终端，连接到新建的容器

> ssh 192.168.1.200 -p 101
The authenticity of host ‘[192.168.1.200]:101 ([192.168.1.200]:101)‘ can‘t be established.
ECDSA key fingerprint is d1:59:f1:09:3b:09:79:6d:19:16:f4:fd:39:1b:be:27.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘[192.168.1.200]:101‘ (ECDSA) to the list of known hosts.
Welcome to Ubuntu 14.04 LTS (GNU/Linux 3.2.0-37-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.

root@890c04ff8d76:~#
测试成功

「二」创建一个带 ssh 服务的基础镜像（修订版）--使用 Dockerfile 创建