我输入了我的shell docker命令
docker pull ubuntu
接下来我输入了
docker images
看了超过30张ubuntu图片。
root@packer-virtualbox-iso:/home# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
ubuntu vivid bd94ae587483 2 weeks ago 131.3 MB
ubuntu 15.04 bd94ae587483 2 weeks ago 131.3 MB
ubuntu vivid-20150427 bd94ae587483 2 weeks ago 131.3 MB
ubuntu utopic-20150427 d191563ad36b 2 weeks ago 194.5 MB
ubuntu 14.10 d191563ad36b 2 weeks ago 194.5 MB
ubuntu utopic d191563ad36b 2 weeks ago 194.5 MB
ubuntu trusty-20150427 07f8e8c5e660 2 weeks ago 188.3 MB
ubuntu latest 07f8e8c5e660 2 weeks ago 188.3 MB
ubuntu trusty 07f8e8c5e660 2 weeks ago 188.3 MB
ubuntu 14.04 07f8e8c5e660 2 weeks ago 188.3 MB
ubuntu 14.04.2 07f8e8c5e660 2 weeks ago 188.3 MB
ubuntu 12.04.5 ac6b0eaa3203 2 weeks ago 132.5 MB
ubuntu precise ac6b0eaa3203 2 weeks ago 132.5 MB
ubuntu 12.04 ac6b0eaa3203 2 weeks ago 132.5 MB
ubuntu precise-20150427 ac6b0eaa3203 2 weeks ago 132.5 MB
ubuntu vivid-20150421 ef8182f3c943 4 weeks ago 131.3 MB
ubuntu utopic-20150418 0b79d1c2df16 4 weeks ago 194.5 MB
ubuntu trusty-20150320 b7cf8f0d9e82 4 weeks ago 188.3 MB
ubuntu precise-20150320 9610cfc68e8d 4 weeks ago 131.9 MB
dylanlindgren/docker-laravel-composer latest 5b7f5b652c0a 6 weeks ago 258.6 MB
ubuntu vivid-20150319.1 751a7482c0de 8 weeks ago 131.7 MB
ubuntu utopic-20150319 59a878f244f6 8 weeks ago 194.4 MB
ubuntu vivid-20150309 19c8c047d0fe 10 weeks ago 131.5 MB
ubuntu utopic-20150228.11 525b6e4a4cc8 10 weeks ago 194.4 MB
ubuntu trusty-20150228.11 2103b00b3fdf 10 weeks ago 188.3 MB
ubuntu precise-20150228.11 5898adab7134 10 weeks ago 131.8 MB
ubuntu vivid-20150218 2427658c75a1 12 weeks ago 117.5 MB
ubuntu utopic-20150211 78949b1e1cfd 12 weeks ago 194.4 MB
ubuntu trusty-20150218.1 2d24f826cb16 12 weeks ago 188.3 MB
ubuntu precise-20150212 1f80e9ca2ac3 12 weeks ago 131.5 MB
ubuntu 14.04.1 5ba9dab47459 3 months ago 188.3 MB
dylanlindgren/docker-laravel-nginx latest 76b33b0ca245 3 months ago 193.6 MB
dylanlindgren/docker-laravel-phpfpm latest bfbb23b41669 3 months ago 318.5 MB
dylanlindgren/docker-laravel-artisan latest a42e33f8719e 5 months ago 229.2 MB
dylanlindgren/docker-laravel-data latest 42d3f5e26286 5 months ago 154.7 MB
ubuntu 12.10 c5881f11ded9 11 months ago 172.2 MB
ubuntu quantal c5881f11ded9 11 months ago 172.2 MB
ubuntu 13.04 463ff6be4238 11 months ago 169.4 MB
ubuntu raring 463ff6be4238 11 months ago 169.4 MB
ubuntu saucy 195eb90b5349 11 months ago 184.6 MB
ubuntu 13.10 195eb90b5349 11 months ago 184.6 MB
ubuntu 10.04 3db9c44f4520 13 months ago 183 MB
ubuntu lucid 3db9c44f4520 13 months ago 183 MB
root@packer-virtualbox-iso:/home# docker version
Client version: 1.1.2
Client API version: 1.13
Go version (client): go1.2.1
Git commit (client): d84a070
Server version: 1.1.2
Server API version: 1.13
Go version (server): go1.2.1
Git commit (server): d84a070
我只期待一个ubuntu图像。为什么docker下载了所有这些？
答案 0 :(得分：2)
如果未在pull中指定标记，则会获得所有标记。这是changed in 1.3，如果您未指定标记，现在将获得latest。
在任何情况下，最好指定一个标签，然后说
docker pull ubuntu:14.04
如果你想要（例如）14.04。
另请注意，某些标记是彼此的别名：您可以看到12.04.5，precise-20150427，12.04和precise都是相同的图像。