proxy_upstream_tries

只配置proxy_upstream_tries

proxy_upstream_tries 3;

不转移 500,502,503,504

10.0.0.10 [2016-01-12T11:33:16+08:00]  504 584 "GET / HTTP/1.1" "-" "curl" "-" "0.002" "up.204:49309" "504" "0.002"
10.0.0.10 [2016-01-12T11:33:17+08:00]  500 537 "GET / HTTP/1.1" "-" "curl" "-" "0.002" "up.157:49180" "500" "0.002"
10.0.0.10 [2016-01-12T10:56:37+08:00]  503 614 "GET / HTTP/1.1" "-" "curl" "-" "0.003" "up.204:49309" "503" "0.003"
10.0.0.10 [2016-01-12T11:33:49+08:00]  502 681 "GET / HTTP/1.1" "-" "curl" "-" "0.001" "up.204:49309" "502" "0.001"

配合proxy_next_upstream，可以实现5xx故障转移并且控制转移次数

    proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
    proxy_upstream_tries 2;

已负载2个后端，仍然没有得到正确响应码，直接返回后一个后端的状态码

10.0.0.10 [2016-01-12T11:37:58+08:00]  500 732 "GET / HTTP/1.1" "-" "curl" "-" "0.002" "up.204:49309, up.157:49180" "502, 500" "0.001, 0.001"

负载2个后端，返回200

10.0.0.10 [2016-01-12T11:37:53+08:00]  200 10224 "GET / HTTP/1.1" "-" "curl" "-" "0.011" "up.204:49309, up.157:49181" "502, 200" "0.001, 0.010"

proxy_next_upstream配置了http_503, http_504, 当有后端返回503或者504时，nginx前端access.log记录的都是502：

10.2.6.12 [2016-01-12T12:02:36+08:00]  502 681 "GET / HTTP/1.1" "-" "curl" "-" "0.003" "up-157:49180, up-204:49309" "502, 502" "0.001, 0.002"
up-157请求失败，显示为502， up-204返回的是504，显示依然为502，这样是正常的吗？

nginx版本：
Tengine version: Tengine/2.1.1 (nginx/1.6.2)