當用nginx做負載均衡的時候，nginx的配置文件如下：

      upstream server_pools {           server 10.0.0.7:80  weight=1;           server 10.0.0.8:80  weight=1;  

當客戶端訪問時出現報錯如下：

  [root@lb02 ~]# curl  www.hahaetiantian.org    

Bad Request

Your browser sent a request that this server could not understand.

Additionally, a 400 Bad Request error was encountered while trying to use an ErrorDocument to handle the request.

[root@lb02 ~]# curl www.hahaetiantian.org www

查看日志報錯并不能找到原因，但是根據400報錯以及對http協議的原理了解得知是因為請求頭的原因，最后在網上找到解決辦法，原因是因為upstream后面的名稱有下劃線使得代理無法識別，修改如下：

      upstream server-pools {           server 10.0.0.7:80  weight=1;           server 10.0.0.8:80  weight=1;

然后再次訪問結果如下：

  [root@lb02 ~]# curl  www.etiantian.org  apache www  [root@lb02 ~]# curl  www.etiantian.org  www