Docker Registry之删除镜像、垃圾回收

<p>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。本文对这一特性进行了体验，具体步骤如下。</p> <h1>1、部署镜像仓库</h1> <h2>（1）启动仓库容器</h2> <pre><code class="language-bash">docker run -d \ -p 5000:5000 \ --restart=always \ --name registry \ -v /data/config.yml:/etc/docker/registry/config.yml \ -v /data/registry:/var/lib/registry \ registry:2</code></pre> <p>说明: 在启动仓库时，需在配置文件config.yml中的storage配置中增加delete=true配置项，允许删除镜像，如下配置文件: cat /data/config.yml</p> <pre><code class="language-bash">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</code></pre> <h2>（2）拉取镜像后上传镜像到私有仓库</h2> <pre><code class="language-bash">docker pull centos:7 docker tag centos:7 localhost:5000/my-centos:7 docker push localhost:5000/my-centos:7</code></pre> <p>说明： 1.浏览器访问可以看到自己上传的镜像，URL如下： <a href="http://172.16.7.199:5000/v2/_catalog">http://172.16.7.199:5000/v2/_catalog</a> 2.上传镜像时记住sha256的值，下面测试删除时会用到，如果不记得可以用命令查看：</p> <pre><code class="language-bash">docker inspect images_name</code></pre> <p>3.此时如何使用IP拉到会报错：</p> <pre><code class="language-bash">docker pull 172.16.7.199:5000/my-centos:7 Error response from daemon: Get https://172.16.7.199:5000/v2/: http: server gave HTTP response to HTTPS client</code></pre> <h2>（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72.6M。</h2> <pre><code class="language-bash">docker exec -it registry /bin/sh /var/lib/registry # du -sh /var/lib/registry/ 72.6M </code></pre> <h1>2.删除镜像</h1> <p>删除registry仓库中的镜像 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,可以用docker inspect localhost:5000/my-centos 命令查看，找到对应的值即可,如下:</p> <pre><code class="language-bash">"RepoDigests": [ "localhost:5000/my-centos@sha256:e4ca2ed0202e76be184e75fb26d14bf974193579039d5573fb2348664deef76e" ],</code></pre> <h2>（1）发送请求，删除刚才上传的镜像</h2> <p>在主机上执行，非在容器内执行</p> <pre><code class="language-bash">curl -I -X DELETE http://172.16.7.199:5000/v2/my-centos/manifests/sha256:e4ca2ed0202e76be184e75fb26d14bf974193579039d5573fb2348664deef76e HTTP/1.1 202 Accepted Docker-Distribution-Api-Version: registry/2.0 X-Content-Type-Options: nosniff Date: Thu, 19 Nov 2020 01:25:40 GMT Content-Length: 0</code></pre> <h2>（2）查看数据大小</h2> <pre><code class="language-bash">docker exec -it registry /bin/sh /var/lib/registry # du -sh /var/lib/registry/ 72.6M </code></pre> <p>可以看到数据大小没有变化（只删除了元数据）</p> <h1>3.垃圾回收</h1> <h2>（1）进行容器执行垃圾回收命令</h2> <p>命令：registry garbage-collect config.yml</p> <pre><code class="language-bash">/var/lib/registry # registry garbage-collect /etc/docker/registry/config.yml my-centos 0 blobs marked, 3 blobs and 0 manifests eligible for deletion blob eligible for deletion: sha256:2d473b07cdd5f0912cd6f1a703352c82b512407db6b05b43f2553732b55df3bc INFO[0000] Deleting blob: /docker/registry/v2/blobs/sha256/2d/2d473b07cdd5f0912cd6f1a703352c82b512407db6b05b43f2553732b55df3bc go.version=go1.11.2 instance.id=bb0b15c5-a336-458f-80b0-919d9ffc53ee service=registry blob eligible for deletion: sha256:8652b9f0cb4c0599575e5a003f5906876e10c1ceb2ab9fe1786712dac14a50cf INFO[0000] Deleting blob: /docker/registry/v2/blobs/sha256/86/8652b9f0cb4c0599575e5a003f5906876e10c1ceb2ab9fe1786712dac14a50cf go.version=go1.11.2 instance.id=bb0b15c5-a336-458f-80b0-919d9ffc53ee service=registry blob eligible for deletion: sha256:e4ca2ed0202e76be184e75fb26d14bf974193579039d5573fb2348664deef76e INFO[0000] Deleting blob: /docker/registry/v2/blobs/sha256/e4/e4ca2ed0202e76be184e75fb26d14bf974193579039d5573fb2348664deef76e go.version=go1.11.2 instance.id=bb0b15c5-a336-458f-80b0-919d9ffc53ee service=registry</code></pre> <h2>（2）查看数据大小</h2> <pre><code class="language-bash">/var/lib/registry # du -sh /var/lib/registry/ 8.0K .</code></pre> <h2>（3）删除残留目录</h2> <p>删除对应的镜像目录即可，如： rm -rf /data/registry/docker/registry/v2/repositories/my-centos</p> <h2>（4）重启docker registry</h2> <p>跟gc方式一样，删除镜像之后要重启docker registry，不然还是会出现相同镜像push不成功的问题。</p> <p>参考资料： <a href="https://www.cnblogs.com/cherylgi/p/13529983.html">https://www.cnblogs.com/cherylgi/p/13529983.html</a> <a href="https://www.cnblogs.com/yunpt/p/10382722.html">https://www.cnblogs.com/yunpt/p/10382722.html</a></p>