nginx upstream没有自动剔除不健康的节点

Nginx的upstream常见分配算法：
轮询
理论上每个请求按时间顺序逐一分配到不同的应用服务器，如果应用服务器down掉，自动剔除，剩下的继续轮询。

以下是常见的配置

upstream test-vue {
    server 192.168.0.66:888;
    server 192.168.0.152:888;
    }
    server {
          listen       11200;
          server_name  localhost;
          location /Reports {
                  proxy_pass http://test-vue;
          }
          location /app{
            proxy_pass http://test-vue;
          }

          error_page   500 502 503 504  /50x.html;
          location = /50x.html {
                  root   html;
              }
    }

但是发现当某个server不可用时并不会自动剔除，在nginx的日志中显示依旧会轮询到错误的节点
并出现以下的错误

upstream timed out (10060: A connection attempt failed 
because the connected party did not properly respond after a period of time,
or established connection failed because connected host has failed to respond) 
while reading response header from upstream, client: 127.0.0.1, server: localhost,

解决方案
将server_name localhost改为127.0.0.1即可