nginx resolver in stream

nginx resolver in stream.md

https://serverfault.com/questions/1010342/nginx-using-resolver-in-a-stream

stream {
    resolver 127.0.0.1 valid=1s;

    # a hack to declare $server_us variable
    map "" $server_us {
        default server.foo.com:22222;
    }

    server {
        listen 11111;
        proxy_pass $server_us;
    }
}