阿里云上的 docker build 死活搞不定了

最简单的，当前目录下有一个 Dockerfile 文件，内容如下：

docker FROM coturn/coturn:4.6.2-debian 

运行docker build -t your-image-name . 进行构建，则出现如下错误信息：

[+] Building 30.1s (2/2) FINISHED docker:default => [internal] load build definition from Dockerfile 0.0s => => transferring dockerfile: 69B 0.0s => ERROR [internal] load metadata for docker.io/coturn/coturn:4.6.2-debian 30.0s ------ > [internal] load metadata for docker.io/coturn/coturn:4.6.2-debian: ------ Dockerfile:1 -------------------- 1 | >>> FROM coturn/coturn:4.6.2-debian 2 | -------------------- ERROR: failed to solve: DeadlineExceeded: DeadlineExceeded: DeadlineExceeded: coturn/coturn:4.6.2-debian: failed to resolve source metadata for docker.io/coturn/coturn:4.6.2-debian: failed to authorize: DeadlineExceeded: failed to fetch anonymous token: Get "https://auth.docker.io/token?scope=repository%3Acoturn%2Fcoturn%3Apull&service=registry.docker.io": dial tcp 31.13.94.7:443: i/o timeout 

这上面的 31.13.94.7 是我自己解析的，因为 auth.docker.io 已经被污染了。用 proxychains 来 curl 上面的链接是可以成功的。

已经按照 https://docs.docker.com/engine/daemon/proxy/#httphttps-proxy 的方式为 docker daemon 设置了 proxy 。