阿里云代理仓库地址为：registry.aliyuncs.com/google_containers
    比如下载
    k8s.gcr.io/coredns:1.6.5
    可以代理为：
    registry.aliyuncs.com/google_containers/coredns:1.6.5

    1. # docker pull registry.aliyuncs.com/google_containers/coredns:1.6.5
    2. # docker tag registry.aliyuncs.com/google_containers/coredns:1.6.5 k8s.gcr.io/coredns:1.6.5
    3. # docker rmi registry.aliyuncs.com/google_containers/coredns:1.6.5