一、需求
由于在测试环境中使用了docker官网的centos 镜像，但是该镜像里面默认没有安装ssh服务，在做测试时又需要开启ssh。所以上网也查了查资料。下面详细的纪录下。在centos 容器内安装ssh后，转成新的镜像用于后期测试使用。
二、镜像定制
第一种方式（手动修改容器镜像）
1.先下载centos镜像
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[root@docker ~]# docker pull centos
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2.启动容器并进行配置
启动容器，
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[root@docker ~]# docker run -it -d --name test-centos1 centos
d72250ecaa5e3e36226a1edd749f494d9f00eddc4143c81ac3565aa4e551791a
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命令注释：-it : 进行交互式操作
-d : 等同于 -d=true,容器将会在后台运行，不然执行一次命令后，退出后，便是exit状态了。
--name : 容器启动后的名字，默认不指定，将会随机产生一个名字。或者使用 -name="containers_name"
centos：使用的镜像名称
进入容器，安装ssh server，以及配置开机启动
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[root@docker ~]# docker exec -it test-centos1 /bin/bash
[root@d72250ecaa5e /]# ifconfig
bash: ifconfig: command not found
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注：命令最后参数 /bin/bash： 指进入容器时执行的命令（command）
我们检查了下容器，暂时安装以下必用的软件吧 net-tools，openssh-server
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[root@d72250ecaa5e /]# yum install openssh-server net-tools -y
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创建ssh 所需的目录，并在根目录创建sshd 启动脚本
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[root@d72250ecaa5e /]# mkdir -pv /var/run/sshd
mkdir: created directory '/var/run/sshd'
[root@d72250ecaa5e /]# cat /auto_sshd.sh
#!/bin/bash
/usr/sbin/sshd -d
[root@d72250ecaa5e /]# chmod +x /auto_sshd.sh
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修改容器内root 的账户密码
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[root@d72250ecaa5e /]# echo "root:iloveworld" | chpasswd
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生成ssh 主机dsa 密钥（不然ssh 该容器时，会出现错误。）
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[root@d72250ecaa5e /]# ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key
[root@d72250ecaa5e /]# ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
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我们加一个history记录的时间功能吧，这样方便后期查看
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echo 'export histtimeformat="%f %t `whoami` "' >> /etc/profile
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ok，配置基本完毕咯。清理命令历史纪录，之后退出容器。现在可以生成一个新的docker 镜像了。
3.配置完成后，进行打包成新的镜像
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[root@docker ~]# docker commit test-centos1 centos_sshd:7.0
sha256:6e3330b30dfff5f029f102874e54cfffffbc37dcf2a4eb7304c817148fbc944d
[root@docker ~]# docker images
repository tag image id created size
centos_sshd 7.0 6e3330b30dff 8 seconds ago 310.1 mb
docker.io/ubuntu latest e4415b714b62 12 days ago 128.1 mb
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命令注释：commit： 提交一个具有新配置的容器成为镜像，后面跟容器的name 或者容器id ，最后是生成新镜像的名字
更新：这条命令更方便以后启动，如下：
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[root@docker ~]# docker commit --change='cmd ["/auto_sshd.sh"]' -c "expose 22" test-centos1 centos_sshd:7.0
sha256:7bb4efd82c4ff1f241cbc57ee45aab1b05d214b1e9fcd51196696c67d480e70b
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命令注释： --change : 将后期使用此镜像运行容器时的命令参数、开放的容器端口提前设置好。
4.验证
查看镜像，并启动新的容器
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[root@docker ~]# docker images
repository tag image id created size
centos_sshd 7.0 7bb4efd82c4f 4 minutes ago 310.1 mb
docker.io/ubuntu latest e4415b714b62 12 days ago 128.1 mb
[root@docker ~]# docker run -d -it --name centos_7.0-1 centos_sshd:7.0
ec17e553d5c4c60865afeb99df8dfd1f4e7d4ba6e1b0d5516f9127f09d1d6356
[root@docker ~]# docker ps -a
container id image command created status ports names
ec17e553d5c4 centos_sshd:7.0 "/auto_sshd.sh" 6 seconds ago up 5 seconds 22/tcp centos_7.0-1
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进行ssh测试，先查看一下该容器的ip，之后ssh。ok
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[root@docker ~]# docker exec centos_7.0-1 hostname -i
172.17.0.4
[root@docker ~]# ssh root@172.17.0.4
the authenticity of host '172.17.0.4 (172.17.0.4)' can't be established.
rsa key fingerprint is 87:88:07:12:ac:0a:90:28:10:e1:9e:eb:1f:d6:c9:9d.
are you sure you want to continue connecting (yes/no)? yes
warning: permanently added '172.17.0.4' (rsa) to the list of known hosts.
root@172.17.0.4's password:
last login: tue nov 29 16:00:49 2016 from gateway
[root@ec17e553d5c4 ~]# w
16:34:17 up 63 days, 7:49, 1 user, load average: 0.00, 0.02, 0.05
user tty from login@ idle jcpu pcpu what
root pts/0 gateway 16:34 1.00s 0.00s 0.00s w
[root@ec17e553d5c4 ~]# ping gateway
ping gateway (172.17.0.1) 56(84) bytes of data.
64 bytes from gateway (172.17.0.1): icmp_seq=1 ttl=64 time=0.048 ms
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第二种方式（推荐：利用dockerfile文件）
我的认为它就像ansible的playbook一样。dockerfile包含创建镜像所需要的全部指令。基于在dockerfile中的指令，我们可以使用docker build命令来创建镜像。通过减少镜像和容器的创建过程来简化部署。
1.创建dockerfile文件
新建一个目录，在里面新建一个dockerfile文件（新建一个的目录，主要是为了和以防和其它dockerfile混乱 ）
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[root@docker ~]# mkdir centos7-dockerfile
[root@docker centos7-dockerfile]# cat dockerfile
# the dockerfile has change add sshd services on centos7.0
#centos7:latest image
from centos:latest
maintainer yifeng,http://www.cnblogs.com/hanyifeng
#install sshd net-tools
run yum install openssh-server net-tools -y
run mkdir /var/run/sshd
#set password for root
run echo 'root:iloveworld' | chpasswd
run sed -i 's/permitrootlogin prohibit-password/permitrootlogin yes/' /etc/ssh/sshd_config
#set history record
env histtimeformat "%f %t "
#fix sshd service:read from socket failed: connection reset by peer?
run ssh-keygen -a
#change timezone cst
run \cp /usr/share/zoneinfo/asia/shanghai /etc/localtime
#open 22 port
expose 22
#auto running sshd service
cmd ["/usr/sbin/sshd","-d"]
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上述文件内容就是一个dockerfile 常见的命令组合。开头带＃号的为注释
文件解释：
from： 必不可少的命令，从某个镜像作为基。如 from <image_name> ，或者 from <image_name>:<tag>. 如果不加tag，默认为latest。先从本地镜像仓库去搜索基镜像，如过本地没有，在去网上docker registry去寻找。
maintainer：标明该dockerfile作者及联系方式，可忽略不写
run：建立新的镜像时，可以执行在系统里的命令，如安装特定的软件以及设置环境变量。
env：设置系统环境变量（注意：写在/etc/profile里的命令在dockerfile这里会不生效，所以为改成env的方式）
expose：开放容器内的端口，但不和宿主机进行映射。方便在宿主机上进行开发测试。（如需映射到宿主机端口，可在运行容器时使用 -p host_port:container_port）
cmd：设置执行的命令，经常用于容器启动时指定的某个操作。如执行自定义脚本服务，或者是执行系统命令。cmd 只能存在一条，如在dockerfile中有多条cmd的话，只有最后一条cmd生效！
2.执行build 创建镜像
使用docker build命令来创建镜像
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[root@docker centos7-dockerfile]# docker build -t centos_sshd_1 .
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-t 选项来docker build新的镜像以便于标记构建的镜像，. 表示当前目录，也可以指定dockerfile 文件所在目录。
下面缩略的内容是构建镜像时的输出，可以看下。
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[root@docker centos7-dockerfile]# docker build -t centos_sshd_1 .
sending build context to docker daemon 4.096 kb
step 1 : from centos:latest
---> 0584b3d2cf6d
step 2 : maintainer yifeng,http://www.cnblogs.com/hanyifeng
---> running in da643b55dc77
---> 1087074d44e4
removing intermediate container da643b55dc77
step 3 : run yum install openssh-server net-tools -y
---> running in 5626d8f0f892
loaded plugins: fastestmirror, ovl
determining fastest mirrors
* base: mirrors.btte.net
* extras: mirrors.tuna.tsinghua.edu.cn
* updates: mirrors.btte.net
resolving dependencies
--> running transaction check
---> package net-tools.x86_64 0:2.0-0.17.20131004git.el7 will be installed
---> package openssh-server.x86_64 0:6.6.1p1-25.el7_2 will be installed
--> processing dependency: openssh = 6.6.1p1-25.el7_2 for package: openssh-server-6.6.1p1-25.el7_2.x86_64
--> processing dependency: fipscheck-lib(x86-64) >= 1.3.0 for package: openssh-server-6.6.1p1-25.el7_2.x86_64
--> processing dependency: libwrap.so.0()(64bit) for package: openssh-server-6.6.1p1-25.el7_2.x86_64
--> processing dependency: libfipscheck.so.1()(64bit) for package: openssh-server-6.6.1p1-25.el7_2.x86_64
--> running transaction check
---> package fipscheck-lib.x86_64 0:1.4.1-5.el7 will be installed
--> processing dependency: /usr/bin/fipscheck for package: fipscheck-lib-1.4.1-5.el7.x86_64
---> package openssh.x86_64 0:6.6.1p1-25.el7_2 will be installed
---> package tcp_wrappers-libs.x86_64 0:7.6-77.el7 will be installed
--> running transaction check
---> package fipscheck.x86_64 0:1.4.1-5.el7 will be installed
--> finished dependency resolution
dependencies resolved
================================================================================
package arch version repository size
================================================================================
installing:
net-tools x86_64 2.0-0.17.20131004git.el7 base 304 k
openssh-server x86_64 6.6.1p1-25.el7_2 updates 436 k
installing for dependencies:
fipscheck x86_64 1.4.1-5.el7 base 21 k
fipscheck-lib x86_64 1.4.1-5.el7 base 11 k
openssh x86_64 6.6.1p1-25.el7_2 updates 435 k
tcp_wrappers-libs x86_64 7.6-77.el7 base 66 k
transaction summary
================================================================================
install 2 packages (+4 dependent packages)
total download size: 1.2 m
installed size: 3.4 m
downloading packages:
public key for fipscheck-lib-1.4.1-5.el7.x86_64.rpm is not installed
warning: /var/cache/yum/x86_64/7/base/packages/fipscheck-lib-1.4.1-5.el7.x86_64.rpm: header v3 rsa/sha256 signature, key id f4a80eb5: nokey
public key for openssh-6.6.1p1-25.el7_2.x86_64.rpm is not installed
--------------------------------------------------------------------------------
total 593 kb/s | 1.2 mb 00:02
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-7-2.1511.el7.centos.2.10.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 : fipscheck-1.4.1-5.el7.x86_64 1/6
installing : fipscheck-lib-1.4.1-5.el7.x86_64 2/6
installing : openssh-6.6.1p1-25.el7_2.x86_64 3/6
installing : tcp_wrappers-libs-7.6-77.el7.x86_64 4/6
installing : openssh-server-6.6.1p1-25.el7_2.x86_64 5/6
installing : net-tools-2.0-0.17.20131004git.el7.x86_64 6/6
verifying : openssh-6.6.1p1-25.el7_2.x86_64 1/6
verifying : openssh-server-6.6.1p1-25.el7_2.x86_64 2/6
verifying : net-tools-2.0-0.17.20131004git.el7.x86_64 3/6
verifying : tcp_wrappers-libs-7.6-77.el7.x86_64 4/6
verifying : fipscheck-lib-1.4.1-5.el7.x86_64 5/6
verifying : fipscheck-1.4.1-5.el7.x86_64 6/6
installed:
net-tools.x86_64 0:2.0-0.17.20131004git.el7
openssh-server.x86_64 0:6.6.1p1-25.el7_2
dependency installed:
fipscheck.x86_64 0:1.4.1-5.el7 fipscheck-lib.x86_64 0:1.4.1-5.el7
openssh.x86_64 0:6.6.1p1-25.el7_2 tcp_wrappers-libs.x86_64 0:7.6-77.el7
complete!
---> 7b249ed8cb54
removing intermediate container 5626d8f0f892
step 4 : run mkdir /var/run/sshd
---> running in fc94a139d438
---> ea2826eccc91
removing intermediate container fc94a139d438
step 5 : run echo 'root:iloveworld' | chpasswd
---> running in ba53283081a7
---> 7ce1ddb5d9c0
removing intermediate container ba53283081a7
step 6 : run sed -i 's/permitrootlogin prohibit-password/permitrootlogin yes/' /etc/ssh/sshd_config
---> running in 4112281a5bf0
---> be21fb6b5b1e
removing intermediate container 4112281a5bf0
step 7 : env histtimeformat "%f %t "
---> running in f2081726e403
---> f3fafca42170
removing intermediate container f2081726e403
step 8 : run ssh-keygen -a
---> running in 2ca9e743dee7
ssh-keygen: generating new host keys: rsa1 rsa dsa ecdsa ed25519
---> 1a927943bee7
removing intermediate container 2ca9e743dee7
step 9 : run \cp /usr/share/zoneinfo/asia/shanghai /etc/localtime
---> running in afd43cc6d4d6
---> 4a0cacf6cd72
removing intermediate container afd43cc6d4d6
step 10 : expose 22
---> running in a03551bc3bcb
---> 3af544106bf4
removing intermediate container a03551bc3bcb
step 11 : cmd /usr/sbin/sshd -d
---> running in f45fe5eb5561
---> d4620c9949b8
removing intermediate container f45fe5eb5561
successfully built d4620c9949b8
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3.查看镜像列表，并创建容器
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[root@docker centos7-dockerfile]# docker images
repository tag image id created size
centos_sshd_1 latest d4620c9949b8 4 minutes ago 308.4 mb
centos_sshd 7.0 7bb4efd82c4f 2 days ago 310.1 mb
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我们刚刚新建的容器已经存在了，现在用它来创建容器
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[root@docker centos7-dockerfile]# docker run -d -it --name centos-two centos_sshd_1
7ae51091c138d249b5e97f6957073e748db278c0f1cf856e968ca78a4aec1a5b
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查看容器
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[root@docker centos7-dockerfile]# docker ps
container id image command created status ports names
7ae51091c138 centos_sshd_1 "/usr/sbin/sshd -d" 16 seconds ago up 15 seconds 22/tcp centos-two
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可以看到容器的command 就是我们之前定义启动ssh 服务的，并且开放了22端口。
现在我们在宿主机上查看下该容器的ip，然后用ssh 链接进去。
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[root@docker ~]# docker exec centos-two hostname -i
172.17.0.7
[root@docker ~]# ssh root@172.17.0.7
the authenticity of host '172.17.0.7 (172.17.0.7)' can't be established.
ecdsa key fingerprint is 7a:38:69:d7:5e:f4:db:e8:3c:ea:92:a4:1a:a1:7b:9a.
are you sure you want to continue connecting (yes/no)? yes
warning: permanently added '172.17.0.7' (ecdsa) to the list of known hosts.
root@172.17.0.7's password:
[root@7ae51091c138 ~]# w
11:19:34 up 65 days, 18:34, 1 user, load average: 0.01, 0.04, 0.05
user tty from login@ idle jcpu pcpu what
root pts/0 gateway 11:19 6.00s 0.00s 0.00s w
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ok。上述就是定义镜像的两种方式，如果还有其它更为方便的还望不吝赐教哈。
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服务器之家。
原文链接：http://www.cnblogs.com/hanyifeng/p/6116067.html