Docker pull下来的镜像（2）

1、通过docker pull ubuntu:12.04 命令拉取镜像，ll发现当前目录并没有什么变化。

2、切换到docker目录

[root@iZwz9fedjw2xvy6fvxfnxgZ zxy]# cd /var/lib/docker
[root@iZwz9fedjw2xvy6fvxfnxgZ docker]# ll
total 36
drwx------ 3 root root 4096 Mar 12 11:45 containers
drwx------ 5 root root 4096 Mar  9 18:36 devicemapper
drwx------ 3 root root 4096 Mar  9 17:44 image
drwxr-x--- 3 root root 4096 Mar  9 17:44 network
drwx------ 4 root root 4096 May  2 10:10 plugins
drwx------ 2 root root 4096 Mar  9 17:44 swarm
drwx------ 2 root root 4096 May  2 10:23 tmp
drwx------ 2 root root 4096 Mar  9 17:44 trust
drwx------ 3 root root 4096 Mar 12 11:45 volumes

3、containers目录下的每一个文件夹代表一个镜像

[root@iZwz9fedjw2xvy6fvxfnxgZ docker]# cd containers/
[root@iZwz9fedjw2xvy6fvxfnxgZ containers]# ll
total 4
drwx------ 4 root root 4096 May  2 10:43 5625c8fcd1413522ebe6ed4bcec116763fefa3d4de4ef93c83079f6fb515b356

4、image目录下的devicemapper文件夹下相关信息

[root@iZwz9fedjw2xvy6fvxfnxgZ containers]# cd ../image/devicemapper/
[root@iZwz9fedjw2xvy6fvxfnxgZ devicemapper]# ll
total 16
drwx------ 4 root root 4096 Mar  9 18:36 distribution
drwx------ 4 root root 4096 Mar  9 17:44 imagedb
drwx------ 5 root root 4096 Mar  9 18:36 layerdb
-rw------- 1 root root  591 May  2 10:23 repositories.json

5、其中repositories.json文件里记录了镜像的信息

[root@iZwz9fedjw2xvy6fvxfnxgZ devicemapper]# cat repositories.json
{"Repositories":{"docker.io/centos":{"docker.io/centos:7.2.1511":"sha256:0a2bad7da9b55f3121f0829de061f002ef059717fc2ed23c135443081200000e","docker.io/centos@sha256:7c47810fd05ba380bd607a1ece3b4ad7e67f5906b1b981291987918cb22f6d4d":"sha256:0a2bad7da9b55f3121f0829de061f002ef059717fc2ed23c135443081200000e"},"docker.io/ubuntu":{"docker.io/ubuntu:12.04":"sha256:5b117edd0b767986092e9f721ba2364951b0a271f53f1f41aff9dd1861c2d4fe","docker.io/ubuntu@sha256:18305429afa14ea462f810146ba44d4363ae76e4c8dfc38288cf73aa07485005":"sha256:5b117edd0b767986092e9f721ba2364951b0a271f53f1f41aff9dd1861c2d4fe"}}}[root@iZwz9fedjw2xvy6fvxfnxgZ