1.2 Docker 镜像管理

 从 docker.com 获取镜像

root@ubuntu:~# docker pull ubuntu    //

latest: Pulling from ubuntu

20ee58809289: Pull complete

a9bf41614bd7: Pull complete

3bb5bd4ed64a: Pull complete

958fcc55b7ad: Pull complete

ac8b2a2b477b: Pull complete

Digest: sha256:6194c351c69cd4d7248d3c45b59b2d941c586607e5c53b3c996709744db0fe2b

Status: Downloaded newer image for ubuntu:latest

 查看本地都有哪些镜像

root@ubuntu:~# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE

ubuntu              latest              ac8b2a2b477b        35 hours ago        125.2 MB

 为 Ubuntu 镜像设置标签为 test1

 再使用使用 docker images 查看，该行的 image id 和 Ubuntu 的一样

root@ubuntu:~# docker tag ubuntu test1

root@ubuntu:~# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE

ubuntu              latest              ac8b2a2b477b        35 hours ago        125.2 MB

test1               latest              ac8b2a2b477b        35 hours ago        125.2 MB


root@ubuntu:~# docker tag ubuntu:v1 test1:v1.0

root@ubuntu:~# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE

ubuntu              v1                  ac8b2a2b477b        36 hours ago        125.2 MB

test1               latest              ac8b2a2b477b        36 hours ago        125.2 MB

test1               v1.0                ac8b2a2b477b        36 hours ago        125.2 MB

 从 docker 仓库搜索 docker 镜像 : docker search [image-name]

root@ubuntu:~# docker search ubuntu

NAME                              DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED

ubuntu                            Ubuntu is a Debian-based Linux operating s...   4293      [OK]

ubuntu-upstart                    Upstart is an event-based replacement for ...   65        [OK]

rastasheep/ubuntu-sshd            Dockerized SSH service, built on top of of...   29                   [OK]

torusware/speedus-ubuntu          Always updated official Ubuntu docker imag...   26                   [OK]

ubuntu-debootstrap                debootstrap --variant=minbase --components...   25        [OK]

nickistre/ubuntu-lamp             LAMP server on Ubuntu                           8                    [OK]

 未全部显示，其中有一项为 STARS，代表这个镜像的热度

 用下载的镜像开启容器

 -i 表示让容器的标准输入打开，-t 表示分配一个伪终端，要把 -i -t 放在镜像名字的前面

root@ubuntu:~# docker run -it ubuntu /bin/bash

root@81678fc4d6c7:/#                     //这个界面就是 -i 选项的结果

root@81678fc4d6c7:/# ls

bin  boot  core  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var

root@81678fc4d6c7:/# w

 05:48:55 up  2:16,  0 users,  load average: 0.02, 0.03, 0.05

USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT

root@81678fc4d6c7:/# exit

exit

root@ubuntu:~#

 用这种方式打开容器，exit 退出后，容器直接关掉了。

 查看运行的容器

root@ubuntu:~# docker ps

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

root@ubuntu:~# docker ps -a

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                     PORTS               NAMES

81678fc4d6c7        ubuntu:latest       "/bin/bash"         6 minutes ago       Exited (0) 4 minutes ago                       happy_newton

 加-a 选项可查看已经退出的容器

 删除指定镜像

 其中后面的参数可以是 tag，如果是 tag 时，实际上是删除该 tag，只要该镜像还有其他 tag，就不会删除该镜像。当后面的参数为镜像 ID 时，就会彻底删除整个镜像，连同所以标签一起删除。

root@ubuntu:~# docker tag ubuntu ubuntu:v1

root@ubuntu:~# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE

ubuntu              latest              ac8b2a2b477b        36 hours ago        125.2 MB

ubuntu              v1                  ac8b2a2b477b        36 hours ago        125.2 MB

test1               latest              ac8b2a2b477b        36 hours ago        125.2 MB

root@ubuntu:~# docker rmi ubuntu:latest

Untagged: ubuntu:latest

root@ubuntu:~# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZE

ubuntu              v1                  ac8b2a2b477b        36 hours ago        125.2 MB

test1               latest              ac8b2a2b477b        36 hours ago        125.2 MB

 查看容器中 Ubuntu 版本

root@81678fc4d6c7:/# cat /etc/lsb-release

DISTRIB_ID=Ubuntu

DISTRIB_RELEASE=16.04

DISTRIB_CODENAME=xenial

DISTRIB_DESCRIPTION="Ubuntu 16.04 LTS"

 内核：内核是根据宿主机得出的

root@81678fc4d6c7:/# uname -a

Linux 81678fc4d6c7 3.13.0-86-generic #130-Ubuntu SMP Mon Apr 18 18:27:15 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux