Nginx在上行响应日志中显示两种不同的状态

Question

我在kubernetes集群中运行nginx-ingress控制器，其中一个请求的日志语句如下所示：

upstream_response_length: 0, 840
upstream_response_time: 60.000, 0.760
upstream_status: 504, 200

我不太明白这是什么意思？Nginx的响应超时等于60秒，然后尝试再次请求(成功)并记录两次请求？

P.S.日志格式配置：

log-format-upstream: >-
      {
      ...
      "upstream_status": "$upstream_status",
      "upstream_response_length": "$upstream_response_length",
      "upstream_response_time": "$upstream_response_time",
      ...
      }

Answer 1

根据ingress-nginx的split_upstream_var方法，它splits了nginx health checks的结果。

因为nginx可以有several upstreams，所以您的日志可以这样解释：

1. First upstream is dead (504)

(第一个上游已死(504))

upstream_response_length: 0 // responce from dead upstream has zero length
upstream_response_time: 60.000 // nginx dropped connection after 60sec
upstream_status: 504 // responce code, upstream doesn't answer

1. Second upstream works (200)

upstream_response_length: 840 // healthy upstream returned 840b 
upstream_response_time: 0.760 // healthy upstream responced in 0.760
upstream_status: 200 // responce code, upstream is ok

附注: JFYI，这是一个很酷的HTTP头状态图

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