id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
992	proxy_next_upstream broken since 1.9.13 including stabe 1.10.1	areznikov-kabam@…		"Hello.
It looks like I found some issue with proxy_next_upstream.
I am running the following configuration:


log_format timed_combined '$remote_addr - $remote_user [$time_local] '
    '""$request"" $upstream_addr http_code:$status $body_bytes_sent '
    '""$http_referer"" ""$http_user_agent"" '
    '$request_time $upstream_response_time $pipe';


gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

    tcp_nodelay on;
    sendfile on;
    tcp_nopush on;

    server {
        listen 8080;

        location / {
            proxy_buffering off;
            proxy_pass http://api_upstream;
            proxy_set_header Host  $host;
            proxy_next_upstream http_503 http_502 timeout error invalid_header;
            proxy_next_upstream_tries 3;
        }

        location /nginx_status {
         stub_status on;
         access_log   off;
         allow 127.0.0.1;
         deny all;
       }

which works fine for nginx versions 1.9.12 and below.

Upstream has about 40 nodejs workers and nginx just proxies requests to it and does gzip compression.

I tried to update to 1.10.1 and discovered issue with proxy_next_upstream when it was sending 502 errors to the ELB without trying to use other upstream workers.

172.31.33.24 - - [03/Jun/2016:21:13:05 +0000] ""POST /*dsdsdsd*****"" HTTP/1.1"" 127.0.0.1:8091 http_code:502 173 ""-"" ""DDDDDDDD/1.0"" 0.001 0.001 .
172.31.16.204 - - [03/Jun/2016:21:13:06 +0000] ""POST*sdsdsdsdsdsd"" HTTP/1.1"" 127.0.0.1:8091 http_code:502 173 ""-"" ""DDDDDDDDDD/1.0"" 0.001 0.001 .

In versions below 1.9.13 it works correctly 
172.31.25.39 - - [03/Jun/2016:23:24:53 +0000] ""GET /rrrrsdsdsdrr HTTP/1.1"" 127.0.0.1:8085, 127.0.0.1:8083 http_code:200 19944 ""-"" ""DDDD/1.0"" 1.211 1.196, 0.015 .
172.31.33.24 - - [03/Jun/2016:23:24:53 +0000] ""POST /sdsdsds  HTTP/1.1"" 127.0.0.1:8085, 127.0.0.1:8102 http_code:200 166 ""-"" ""SDDDDDD"" 0.882 0.864, 0.018 .
172.31.25.39 - - [03/Jun/2016:23:24:53 +0000] ""POST /dddddr HTTP/1.1"" 127.0.0.1:8085, 127.0.0.1:8091 http_code:200 1563 ""-"" ""DDDD/1.0"" 0.150 0.001, 0.149 ."	defect	closed	major		nginx-core	1.9.x	worksforme	proxy_next_upstream	areznikov@…	Linux array-*******************.io 3.13.0-46-generic #79-Ubuntu SMP Tue Mar 10 20:06:50 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux	"nginx version: nginx/1.9.13
built by gcc 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) 
configure arguments: --prefix=/opt/nginx/1.9.13 --without-http_rewrite_module --with-cc-opt=-Werror --with-http_stub_status_module"