学会了镜像的构建，下面研究如何在多个Docker Host上使用镜像
1、用相同的Dockerfile 在其他host上进行构建
2、将镜像上传到公共的Registry（比如 Docker Hub）上，其他host可以直接下载使用
3、搭建私有的Registry 供内部使用
为了方便使用，镜像的命名比较重要。
1、标准的镜像名称 [ image name ] = [ repository ] : [ tag ]
busybox:latest
2、latest tag 当不指明tag的时候，tag均为latest，仅此而已
docker build -t myimage
docker pull ubuntu
3、tag命名最佳实践
一个高效的版本命名方案可以让用户更清楚的知道当前使用的是哪个镜像，同时还能保持足够的灵活性。
这里借鉴软件版本的命名方式。
每个repository可以有多个tag，而多个tag可能对应的是同一版镜像
timage:1 始终指向1分支中的最新版本
timage:1.9 始终指向1.9分支中的最新版本
timage:latest 始终指向所有版本中的最新版
如果想下载特定版本 docker pull timage:1.9.1
root@docker-lab:~/018# docker build -t timage-v1.9.1 .
Sending build context to Docker daemon 2.048kB
Step 1/2 : FROM busybox
---> 3a093384ac30
Step 2/2 : CMD echo testimage
---> Using cache
---> c6f978f27d36
Successfully built c6f978f27d36
Successfully tagged timage-v1.9.1:latest
root@docker-lab:~/018# docker images timage-v1.9.1
REPOSITORY TAG IMAGE ID CREATED SIZE
timage-v1.9.1 latest c6f978f27d36 4 minutes ago 1.2MB
root@docker-lab:~/018# docker tag timage-v1.9.1 timage:1
root@docker-lab:~/018# docker tag timage-v1.9.1 timage:1.9
root@docker-lab:~/018# docker tag timage-v1.9.1 timage:1.9.1
root@docker-lab:~/018# docker tag timage-v1.9.1 timage:latest
root@docker-lab:~/018# docker images timage
REPOSITORY TAG IMAGE ID CREATED SIZE
timage 1 c6f978f27d36 4 minutes ago 1.2MB
timage 1.9 c6f978f27d36 4 minutes ago 1.2MB
timage 1.9.1 c6f978f27d36 4 minutes ago 1.2MB
timage latest c6f978f27d36 4 minutes ago 1.2MB
root@docker-lab:~/018# docker build -t timage-v1.9.2 .
Sending build context to Docker daemon 2.048kB
Step 1/2 : FROM busybox
---> 3a093384ac30
Step 2/2 : CMD echo testimage
---> Using cache
---> c6f978f27d36
Successfully built c6f978f27d36
Successfully tagged timage-v1.9.2:latest
root@docker-lab:~/018# docker tag timage-v1.9.2 timage:1
root@docker-lab:~/018# docker tag timage-v1.9.2 timage:1.9
root@docker-lab:~/018# docker tag timage-v1.9.2 timage:1.9.2
root@docker-lab:~/018# docker tag timage-v1.9.2 timage:latest
root@docker-lab:~/018# docker images timage
REPOSITORY TAG IMAGE ID CREATED SIZE
timage 1 c6f978f27d36 5 minutes ago 1.2MB
timage 1.9 c6f978f27d36 5 minutes ago 1.2MB
timage 1.9.1 c6f978f27d36 5 minutes ago 1.2MB
timage 1.9.2 c6f978f27d36 5 minutes ago 1.2MB
timage latest c6f978f27d36 5 minutes ago 1.2MB
root@docker-lab:~/018# docker build -t timage-v2.0.0 .
Sending build context to Docker daemon 2.048kB
Step 1/2 : FROM busybox
---> 3a093384ac30
Step 2/2 : CMD echo testimage
---> Using cache
---> c6f978f27d36
Successfully built c6f978f27d36
Successfully tagged timage-v2.0.0:latest
root@docker-lab:~/018# docker tag timage-v2.0.0 timage:2
root@docker-lab:~/018# docker tag timage-v2.0.0 timage:2.0
root@docker-lab:~/018# docker tag timage-v2.0.0 timage:2.0.0
root@docker-lab:~/018# docker tag timage-v2.0.0 timage:latest
root@docker-lab:~/018# docker images timage
REPOSITORY TAG IMAGE ID CREATED SIZE
timage 1 c6f978f27d36 6 minutes ago 1.2MB
timage 1.9 c6f978f27d36 6 minutes ago 1.2MB
timage 1.9.1 c6f978f27d36 6 minutes ago 1.2MB
timage 1.9.2 c6f978f27d36 6 minutes ago 1.2MB
timage 2 c6f978f27d36 6 minutes ago 1.2MB
timage 2.0 c6f978f27d36 6 minutes ago 1.2MB
timage 2.0.0 c6f978f27d36 6 minutes ago 1.2MB
timage latest c6f978f27d36 6 minutes ago 1.2MB
1 root@docker-lab:~/018# docker build -t timage-v1.9.1 . 2 Sending build context to Docker daemon 2.048kB 3 Step 1/2 : FROM busybox 4 ---> 3a093384ac30 5 Step 2/2 : CMD echo testimage 6 ---> Using cache 7 ---> c6f978f27d36 8 Successfully built c6f978f27d36 9 Successfully tagged timage-v1.9.1:latest 10 root@docker-lab:~/018# docker images timage-v1.9.1 11 REPOSITORY TAG IMAGE ID CREATED SIZE 12 timage-v1.9.1 latest c6f978f27d36 4 minutes ago 1.2MB 13 root@docker-lab:~/018# docker tag timage-v1.9.1 timage:1 14 root@docker-lab:~/018# docker tag timage-v1.9.1 timage:1.9 15 root@docker-lab:~/018# docker tag timage-v1.9.1 timage:1.9.1 16 root@docker-lab:~/018# docker tag timage-v1.9.1 timage:latest 17 root@docker-lab:~/018# docker images timage 18 REPOSITORY TAG IMAGE ID CREATED SIZE 19 timage 1 c6f978f27d36 4 minutes ago 1.2MB 20 timage 1.9 c6f978f27d36 4 minutes ago 1.2MB 21 timage 1.9.1 c6f978f27d36 4 minutes ago 1.2MB 22 timage latest c6f978f27d36 4 minutes ago 1.2MB 23 root@docker-lab:~/018# docker build -t timage-v1.9.2 . 24 Sending build context to Docker daemon 2.048kB 25 Step 1/2 : FROM busybox 26 ---> 3a093384ac30 27 Step 2/2 : CMD echo testimage 28 ---> Using cache 29 ---> c6f978f27d36 30 Successfully built c6f978f27d36 31 Successfully tagged timage-v1.9.2:latest 32 root@docker-lab:~/018# docker tag timage-v1.9.2 timage:1 33 root@docker-lab:~/018# docker tag timage-v1.9.2 timage:1.9 34 root@docker-lab:~/018# docker tag timage-v1.9.2 timage:1.9.2 35 root@docker-lab:~/018# docker tag timage-v1.9.2 timage:latest 36 root@docker-lab:~/018# docker images timage 37 REPOSITORY TAG IMAGE ID CREATED SIZE 38 timage 1 c6f978f27d36 5 minutes ago 1.2MB 39 timage 1.9 c6f978f27d36 5 minutes ago 1.2MB 40 timage 1.9.1 c6f978f27d36 5 minutes ago 1.2MB 41 timage 1.9.2 c6f978f27d36 5 minutes ago 1.2MB 42 timage latest c6f978f27d36 5 minutes ago 1.2MB 43 root@docker-lab:~/018# docker build -t timage-v2.0.0 . 44 Sending build context to Docker daemon 2.048kB 45 Step 1/2 : FROM busybox 46 ---> 3a093384ac30 47 Step 2/2 : CMD echo testimage 48 ---> Using cache 49 ---> c6f978f27d36 50 Successfully built c6f978f27d36 51 Successfully tagged timage-v2.0.0:latest 52 root@docker-lab:~/018# docker tag timage-v2.0.0 timage:2 53 root@docker-lab:~/018# docker tag timage-v2.0.0 timage:2.0 54 root@docker-lab:~/018# docker tag timage-v2.0.0 timage:2.0.0 55 root@docker-lab:~/018# docker tag timage-v2.0.0 timage:latest 56 root@docker-lab:~/018# docker images timage 57 REPOSITORY TAG IMAGE ID CREATED SIZE 58 timage 1 c6f978f27d36 6 minutes ago 1.2MB 59 timage 1.9 c6f978f27d36 6 minutes ago 1.2MB 60 timage 1.9.1 c6f978f27d36 6 minutes ago 1.2MB 61 timage 1.9.2 c6f978f27d36 6 minutes ago 1.2MB 62 timage 2 c6f978f27d36 6 minutes ago 1.2MB 63 timage 2.0 c6f978f27d36 6 minutes ago 1.2MB 64 timage 2.0.0 c6f978f27d36 6 minutes ago 1.2MB 65 timage latest c6f978f27d36 6 minutes ago 1.2MB