执行docker commit前的备忘录
环境 –
在VirtualBox上安装CentOS 6.5。
安装Docker
# yum install docker-io
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: ftp.tsukuba.wide.ad.jp
* extras: ftp.tsukuba.wide.ad.jp
* updates: centos.tt.co.kr
Setting up Install Process
No package docker-io available.
Error: Nothing to do
按照文件的要求安装EPEL并进行再次尝试。
# rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
Retrieving http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
warning: /var/tmp/rpm-tmp.SXgnRV: Header V3 RSA/SHA256 Signature, key ID 0608b895: NOKEY
Preparing... ########################################### [100%]
1:epel-release ########################################### [100%]
# yum install docker-io
# docker -v
Docker version 1.3.2, build 39fa2fa/1.3.2
# service docker start
Starting cgconfig service: [ OK ]
Starting docker: [ OK ]
用root用户创建容器。
这个地方很容易理解。结果来看，在后续的操作中，我觉得还是应该允许一般用户进行以下的操作。
# docker run centos /bin/echo "hello world"
Unable to find image 'centos' locally
centos:latest: The image you are pulling has been verified
511136ea3c5a: Pull complete
5b12ef8fd570: Pull complete
34943839435d: Pull complete
Status: Downloaded newer image for centos:latest
hello world
# docker run centos /bin/cat /etc/redhat-release
CentOS Linux release 7.0.1406 (Core)
我动了。
尝试从Docker Hub上拉取镜像。
# docker pull centos:centos6
# docker run centos:centos6 /bin/cat /etc/redhat-release
CentOS release 6.6 (Final)
启动容器
# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
centos centos6 25c5298b1a36 2 weeks ago 215.8 MB
centos latest 34943839435d 2 weeks ago 224 MB
# docker run --name="intro" -t -i -d 25c5 /bin/bash
722f3a7dad6897d9749ac93b979ae8d8c420220af8728bc326cc76f32ae857aa
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
722f3a7dad68 centos:centos6 "/bin/bash" 14 seconds ago Up 13 seconds intro
# docker attach 722f3a7dad68
[root@722f3a7dad68 /]#
保存修改
进行修改。例如尝试添加用户。
[root@722f3a7dad68 /]# useradd myuser
[root@722f3a7dad68 /]# tail -1 /etc/passwd
myuser:x:500:500::/home/myuser:/bin/bash
按下Ctrl+P和Ctrl+Q进行分离。不是退出（exit）。之后提交(commit)。
# docker commit -m "useradd" 722f3a7dad68 mycontainer
4d15b0eac3b0f2e41b607fef77b6bccf507f709cf8d4453d6e8c44e20e4a877a
# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
mycontainer latest 4d15b0eac3b0 47 seconds ago 215.9 MB
centos centos6 25c5298b1a36 2 weeks ago 215.8 MB
centos latest 34943839435d 2 weeks ago 224 MB
我的容器的新映像4d15b0eac3b0已经创建完毕，或许名字(mycontainer)取得太随意了。
如果不保存更改
再次附加并添加另一个用户。
[root@722f3a7dad68 /]# useradd myuser2
[root@722f3a7dad68 /]# tail -2 /etc/passwd
myuser:x:500:500::/home/myuser:/bin/bash
myuser2:x:501:501::/home/myuser2:/bin/bash
从保存的镜像中启动容器，然后分离
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
722f3a7dad68 centos:centos6 "/bin/bash" 50 minutes ago Up 50 minutes intro
# docker run --name="intro2" -t -i -d 4d /bin/bash
4942e5a4d043209032b0c2e76d6cbadfbc3d63f5b6bfaa2e4cf5dda6108d8997
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4942e5a4d043 mycontainer:latest "/bin/bash" 13 seconds ago Up 12 seconds intro2
722f3a7dad68 centos:centos6 "/bin/bash" 52 minutes ago Up 51 minutes intro
# docker attach 49
[root@4942e5a4d043 /]# tail -2 /etc/passwd
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
myuser:x:500:500::/home/myuser:/bin/bash
从已保存的更改点重新开始。（保存后没有添加第二个用户）
因为弄乱了，所以要整理集装箱。
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4942e5a4d043 mycontainer:latest "/bin/bash" 5 minutes ago Up 5 minutes intro2
722f3a7dad68 centos:centos6 "/bin/bash" 56 minutes ago Up 56 minutes intro
# docker stop 4942e5a4d043
4942e5a4d043
# docker stop 722f3a7dad68
722f3a7dad68
# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
由于停止仍然残留，因此执行rm命令。
# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4942e5a4d043 mycontainer:latest "/bin/bash" 14 minutes ago Exited (-1) 8 minutes ago intro2
722f3a7dad68 centos:centos6 "/bin/bash" About an hour ago Exited (-1) 8 minutes ago intro
# docker rm 4942e5a4d043
4942e5a4d043
# docker rm 722f3a7dad68
722f3a7dad68
# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
整理图像
# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
mycontainer latest 4d15b0eac3b0 50 minutes ago 215.9 MB
centos centos6 25c5298b1a36 2 weeks ago 215.8 MB
centos latest 34943839435d 2 weeks ago 224 MB
# docker rmi 4d15b0eac3b0
Untagged: mycontainer:latest
Deleted: 4d15b0eac3b0f2e41b607fef77b6bccf507f709cf8d4453d6e8c44e20e4a877a
# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
centos centos6 25c5298b1a36 2 weeks ago 215.8 MB
centos latest 34943839435d 2 weeks ago 224 MB
让普通用户试试看
按照文件的要求，将普通用户添加到docker组中。
$ sudo usermod -a -G docker satzz
$ sudo vi /etc/sysconfig/docker
# /etc/sysconfig/docker
#
# Other arguments to pass to the docker daemon process
# These will be parsed by the sysv initscript and appended
# to the arguments list passed to docker -d
#other_args=
other_args="-H 127.0.0.1:4243" # add
$ export DOCKER_HOST=tcp://127.0.0.1:4243
$ docker pull centos:centos6
centos:centos6: The image you are pulling has been verified
511136ea3c5a: Already exists
5b12ef8fd570: Already exists
25c5298b1a36: Already exists
Status: Image is up to date for centos:centos6
有现有的图像可用，DOCKER_HOST应该写在.bashrc等文件中。
$ docker run --name="intro" -t -i -d 25c5 /bin/bash
0c890bd6d900ae4cc609fb85b7ea36ba91b93bd96bd8c6628f8aa717b4dcdd2c
$ docker attach 0c890bd6d900ae4cc609fb85b7ea36ba91b93bd96bd8c6628f8aa717b4dcdd2c
[root@0c890bd6d900 /]#
我能够运行并附加。
如果选择exit而不是detach会发生什么？
$ docker run --name="intro" -t -i -d 25c5 /bin/bash
3b2d8ffaaac414f3a5e96fddb2ff7303be8c6db5a615cca2f81b9cabde2d7410
$ docker attach 3b2d8ffaaac414f3a5e96fddb2ff7303be8c6db5a615cca2f81b9cabde2d7410
[root@3b2d8ffaaac4 /]# exit
exit
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3b2d8ffaaac4 centos:centos6 "/bin/bash" 15 seconds ago Exited (0) 3 seconds ago intro
$ docker attach 3b2d8ffaaac4
2014/12/18 18:49:59 You cannot attach to a stopped container, start it first
STATUS从UP变为Exited。由于它没有运行，无法进行附加操作，但只要启动它，就可以进行附加操作。
$ docker start 3b2d8ffaaac4
3b2d8ffaaac4
$ docker attach 3b2d8ffaaac4
[root@3b2d8ffaaac4 /]#
