Because the last request before this 502-request was almost 20 minutes ago, so there was no error log in 20 minutes before this 502-request.
This is some strange, and only happens very rarely. I know it's difficult to debug this if not reproduced. I just ask here to see if this is a known question. Thanks for your answer. Wu At 2017-05-12 18:39:12, "Maxim Dounin" <[email protected]> wrote: >Hello! > >On Fri, May 12, 2017 at 01:24:14PM +0800, Wu Bingzheng wrote: > >> >> The last request before this 502 request is almost 20 minutes ago and its >> response code is 200. >> >> The proxy_next_upstream conf: >> proxy_next_upstream error timeout invalid_header http_502 http_503 >> http_504; >> >> Here is the access log. The upstream server 192.168.0.6 is DOWN. The line-10 >> is the 502 request: >> >> 1 [03/May/2017:14:35:38 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.6:8181, 192.168.0.5:8181" 0.012 0.001, 0.011 >> 2 [03/May/2017:14:35:38 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.013 0.013 >> 3 [03/May/2017:14:54:30 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.206 0.206 >> 4 [03/May/2017:15:03:08 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.154 0.154 >> 5 [03/May/2017:15:40:51 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.6:8181, 192.168.0.5:8181" 0.012 0.000, 0.012 >> 6 [03/May/2017:15:40:51 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.014 0.014 >> 7 [03/May/2017:15:40:51 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.016 0.016 >> 8 [03/May/2017:15:40:51 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.017 0.017 >> 9 [03/May/2017:15:40:51 -0400] "POST /x/y HTTP/1.1" 200 >> "192.168.0.5:8181" 0.011 0.011 >> 10 [03/May/2017:15:59:06 -0400] "POST /x/y HTTP/1.1" 502 >> "192.168.0.6:8181, test_backend" 0.000 0.000, 0.000 >> 11 [03/May/2017:15:59:07 -0400] "POST /x/y HTTP/1.1" 200 >> "10.255.222.206:8181" 0.260 0.260 > >Looking into response status code in access logs is not enough to >understand if a server is up or down. For at least the following >reasons: > >- there might be over requests currently in flight which are not > yet logged; > >- errors may occur while sending response body, and hence status > code will not show if there was an error. > >It is usually a good idea to look into error logs instead. > >-- >Maxim Dounin >http://nginx.org/ >_______________________________________________ >nginx mailing list >[email protected] >http://mailman.nginx.org/mailman/listinfo/nginx _______________________________________________ nginx mailing list [email protected] http://mailman.nginx.org/mailman/listinfo/nginx
