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Docker Registry镜像管理

Registry删除镜像、垃圾回收

Docker仓库在2.1版本中支持了删除镜像的API,但这个删除操作只会删除镜像元数据,不会删除层数据。在2.4版本中对这一问题进行了解决,增加了一个垃圾回收命令,删除未被引用的层数据。

部署镜像仓库

(1)启动仓库容器

$ sudo docker run -d -v /home/config.yml:/etc/docker/registry/config.yml -p 5000:5000 --name test_registry registry:2.4.1

这里需要说明一点,在启动仓库时,需在配置文件中的storage配置中增加delete=true配置项,允许删除镜像,本次试验采用如下配置文件:

$ cat /home/config.yml
version: 0.1
log:
 fields:
 service: registry
storage:
 delete:
  enabled: true
 cache:
  blobdescriptor: inmemory
 filesystem:
  rootdirectory: /var/lib/registry
http:
 addr: :5000
 headers:
  X-Content-Type-Options: [nosniff]
health:
 storagedriver:
 enabled: true
 interval: 10s
 threshold: 3

 (2)上传镜像

$ docker tag centos 192.168.119.1:5000/xcb/centos
$ docker push 192.168.119.1:5000/xcb/centos
Thepushrefersto a repository [192.168.119.1:5000/xcb/centos]
5f70bf18a086: Pushed 
4012bfb3d628: Pushed
latest: digest: sha256:5b367dbc03f141bb5246b0dff6d5fc9c83d8b8d363d0962f3b7d344340e458f6 size: 1331

(3)查看数据进行仓库容器中,通过du命令查看大小,可以看到当前仓库数据大小为61M。

$ docker exec -it test_registry /bin/bash
$ du -sch /var/lib/registry
61M .
61M total

删除镜像

删除镜像对应的API如下:

DELETE /v2/<name>/manifests/<reference>

name:镜像名称

reference: 镜像对应sha256值

(1)发送请求,删除刚才上传的镜像

$ curl -I -X DELETE http://192.168.119.1:5000/v2/xcb/centos/manifests/sha256:5b367dbc03f141bb5246b0dff6d5fc9c83d8b8d363d0962f3b7d344340e458f6
HTTP/1.1 202 Accepted
Docker-Distribution-Api-Version: registry/2.0
X-Content-Type-Options: nosniff
Date: Wed, 06 Jul 2016 09:24:15 GMT
Content-Length: 0
Content-Type: text/plain; charset=utf-8

(2)查看数据大小

$ /var/lib/registry# du -sch
61M .
61M total

可以看到数据大小没有变化(只删除了元数据)

垃圾回收

(1)进行容器执行垃圾回收命令

命令:

registry garbage-collect config.yml
$ /var/lib/registry# registry garbage-collect /etc/docker/registry/config.yml
INFO[0000] Deletingblob: /docker/registry/v2/blobs/sha256/96/9687900012707ea43dea8f07a441893903dd642d60668d093c4d4d2c5bedd9eb go.version=go1.6.2 instance.id=4d875a6c-764d-4b2d-a7c2-4e85ec2b9d58
INFO[0000] Deletingblob: /docker/registry/v2/blobs/sha256/a3/a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4 go.version=go1.6.2 instance.id=4d875a6c-764d-4b2d-a7c2-4e85ec2b9d58
INFO[0000] Deletingblob: /docker/registry/v2/blobs/sha256/c3/c3bf6062f354b9af9db4481f24f488da418727673ea76c5162b864e1eea29a4e go.version=go1.6.2 instance.id=4d875a6c-764d-4b2d-a7c2-4e85ec2b9d58
INFO[0000] Deletingblob: /docker/registry/v2/blobs/sha256/5b/5b367dbc03f141bb5246b0dff6d5fc9c83d8b8d363d0962f3b7d344340e458f6 go.version=go1.6.2 instance.id=4d875a6c-764d-4b2d-a7c2-4e85ec2b9d58

(2)查看数据大小

$ /var/lib/registry# du -sch            
108K .
108K total

可以看到镜像数据已被删除,从61M变成了108K。