1. 鉴权介绍

自建docker registry比较简单, 但是docker registry的鉴权如何能和现有的系统结合就很优雅了, 我们可以自定义一些规则允许/拒绝某些账户拉取和推送或者只推送. 实现的基本思路:

  • 自定义一个docker registry镜像, 可以基于现有官方镜像, 在定义镜像中指定鉴权服务地址
  • 自定一个鉴权的镜像, 在这个镜像中可以包含自定义的鉴权逻辑和仓库的ACL
  • 部署上面两个服务

2. 自定义Docker Registory

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FROM centos:7.6.1810

RUN mkdir -p /var/lib/registry

EXPOSE 5000

ENV REGISTRY_AUTH token
ENV REGISTRY_AUTH_TOKEN_REALM https://${DOMAIN}/auth
ENV REGISTRY_AUTH_TOKEN_SERVICE "Docker registry"
ENV REGISTRY_AUTH_TOKEN_ISSUER "Auth Service"
ENV REGISTRY_AUTH_TOKEN_ROOTCERTBUNDLE /ssl/domain.crt
ENV REGISTRY_HTTP_TLS_CERTIFICATE /ssl/domain.crt
ENV REGISTRY_HTTP_TLS_KEY /ssl/domain.key
ENV REGISTRY_HTTP_SECRET w87reoqweifgqoe

COPY config/config.yml /etc/docker/registry/config.yml
COPY ssl/ /ssl/
COPY ./cert/digicert-ng.pem.trust /etc/pki/ca-trust/source/anchors/digicert-ng.pem
RUN update-ca-trust extract

CMD ["/bin/registry", "serve", "/etc/docker/registry/config.yml"]

3. 自定义权限镜像(重点)

3.1 镜像

这里用到了一个开源的功能很全的基础镜像: cesanta/docker_auth, 为了理解镜像配置需要学习这个镜像的基本知识.

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FROM cesanta/docker_auth as cesanta
FROM python:2.7.18-alpine
COPY --from=cesanta /docker_auth/ /docker_auth/

ARG CICD_SECRET
ENV CICD_SECRET=${CICD_SECRET}

ENTRYPOINT ["/docker_auth/auth_server"]
CMD ["-alsologtostderr=true", "-log_dir=/logs", "/config/extAuth.yml"]
EXPOSE 5001

COPY config/ /config/
COPY ssl/ /ssl/
COPY extensions/ /extensions/

3.2 镜像配置

上面的镜像中有两个配置config/extensions

  • config配置参, 如下配置配置了auth和registry通信是https的证书,token的issuer, 扩展授权方式ext_auth, 还有acl, 这些都是关键的配置
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    server: # Server settings.
      addr: ":5001"

      certificate: "/ssl/domain.crt"
      key: "/ssl/domain.key"

    token: # Settings for the tokens.
      issuer: "Auth Service" # Must match issuer in the Registry config.
      expiration: 900
    ext_auth:
      command: "/extensions/ext_auth.sh" # Can be a relative path too; $PATH works.
      args: [""]
    acl:
      - match: { ip: "127.0.0.0/8" }
        actions: ["*"]
        comment: "Allow everything from localhost (IPv4)"
      - match: { account: "/.+/", type: "registry", name: "catalog" }
        actions: ["*"]
        comment: "Logged in users can query the catalog."
      - match: { labels: { "group": "CICD" } }
        actions: ["*"]
        comment: "User assigned to group 'CICD' is able to push"
      - match: { account: "/.+/" }
        actions: ["pull"]
        comment: "Logged in users can pull all images."
  • extensions配置是基于上面的配置的ext_auth,例如是个脚本:
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    read u p

    if [ "$u" == "cicd" ]; then
      if [ "$p" == "$CICD_SECRET" ]; then
        echo '{"labels": {"group": ["CICD"]}}'
        exit 0
      fi
      exit 1
    fi

    python /extensions/boxlogin.py "$u" "$p"

    exit $?

3.3 鉴权镜像项目目录

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.
├── Dockerfile
├── build.sh
├── config
│   └── extAuth.yml
├── extensions
│   ├── boxlogin.py
│   └── ext_auth.sh
└── ssl
    ├── domain.crt
    ├── domain.csr
    └── domain.key

ext_auth.sh是配置所需要的shell脚本, 脚本不要配置标准输出, 退出的code是0或者1. boxlogin.py的Python脚本可以自定更灵活的逻辑, 比如发送Restful请求到现有服务, 判断登录是否成功, 成功则exit(0),否则exit(1).

4. 部署

有了镜像部署就简单了:

  • 部署registry并暴露一个访问地址
  • 部署auth并部署并暴露一个访问地址
  • 两个访问地址IP或者域名一致,但是auth的端口是5001
    部署完了保证两个服务各自都可以访问, 可以通过如下命令分别查看两个服务是否正常:
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    curl https://my.registory.cn/v2/
    curl https://my.registory.cn:5001/auth

5. Troubleshooting