nginx log中有多个upstream_response_t

现象

nginx log中出现两个或者多个逗号分隔的upstream_response_time和upstream_addr，说明upstream到两个server上了

我遇到的是有两个第一个超时，第二个正常

参考文档：ngx_http_upstream_module

If an error occurs during communication with a server, the request will be passed to the next server, and so on until all of the functioning servers will be tried. If a successful response could not be obtained from any of the servers, the client will receive the result of the communication with the last server.

分析

也就是说，nginx会在第一个server失败的时候，请求下一个server，所以会有两个或者多个，其实只有最后一个成功了