Upstream conenction timeout error in nginx(Urgent help needed)

Hi,

We have nginx configured as reverse proxy for our application servers. It also loadbalances connections to the two tomcat application servers using an upstream.

Below is our upstream configuration:

---------------------------
upstream prod {

sticky name=prodx path=/pc;
server 10.x.x.x:8084 ;
server 10.x.x.x:8084 ;
}
----------------------------

We are noticing frequent connection timed out errors in the debug error log and also our users are getting session time outs.

Below are the errors we noted in the logs:

--------------------------------------------------------------------------------------------------------------------------------------
2018/02/27 13:13:01 [debug] 25552#0: *1365757 input buf 0000555555AB40C0 4096
2018/02/27 13:13:01 [debug] 25552#0: *1365757 malloc: 0000555555AB50D0:4096
2018/02/27 13:13:01 [debug] 25552#0: *1365757 readv: 1, last:4096
2018/02/27 13:13:01 [debug] 25552#0: *1365757 pipe recv chain: 325
2018/02/27 13:13:01 [debug] 25552#0: *1365757 readv: 1, last:3771
2018/02/27 13:13:01 [debug] 25552#0: *1365757 readv() not ready (11: Resource temporarily unavailable)
2018/02/27 13:13:01 [debug] 25552#0: *1365757 pipe recv chain: -2
2018/02/27 13:13:01 [debug] 25552#0: *1365757 pipe buf in s:1 t:1 f:0 0000555555B435C0, pos 0000555555B43703, size: 3773 file: 0, size: 0
2018/02/27 13:13:01 [debug] 25552#0: *1365757 pipe buf in s:1 t:1 f:0 0000555555AB40C0, pos 0000555555AB40C0, size: 4096 file: 0, size: 0
2018/02/27 13:13:01 [debug] 25552#0: *1365757 pipe buf free s:0 t:1 f:0 0000555555AB50D0, pos 0000555555AB50D0, size: 325 file: 0, size: 0
2018/02/27 13:13:01 [debug] 25552#0: *1365757 pipe length: 327
.
.
.
.
2018/02/27 13:27:15 [debug] 25553#0: *1398223 SSL_read: -1
2018/02/27 13:27:15 [debug] 25553#0: *1398223 SSL_get_error: 2
2018/02/27 13:27:15 [debug] 25553#0: *1398223 free: 0000555555B4FE00
2018/02/27 13:27:15 [debug] 25552#0: *1404063 event timer del: 31: 1519756035496
2018/02/27 13:27:15 [debug] 25552#0: *1404063 http wait request handler
2018/02/27 13:27:15 [info] 25552#0: *1404063 client timed out (110: Connection timed out) while waiting for request, client: 108.254.97.167, server: 0.0.0.0:443
2018/02/27 13:27:15 [debug] 25552#0: *1404063 close http connection: 31
2018/02/27 13:27:15 [debug] 25552#0: *1404063 SSL_shutdown: 1
2018/02/27 13:27:15 [debug] 25552#0: *1404063 reusable connection: 0
2018/02/27 13:27:15 [debug] 25552#0: *1404063 free: 0000000000000000
2018/02/27 13:27:15 [debug] 25552#0: *1404063 free: 0000555555B17DD0, unused: 16



2018/02/25 15:39:55 [error] 3640#0: *5271942 upstream timed out (110: Connection timed out) while connecting to upstream, client: X.X.X.X, server: Testtemp.com, request: "GET /mediawiki-1.16.0beta2/skins/common/quickbar.css HTTP/1.1", upstream: "http://x.x.x.x:80/mediawiki-1.16.0beta2/skins/common/quickbar.css", host: "x.x.x.x"

2018/02/25 15:39:55 [error] 3639#0: *5271969 upstream timed out (110: Connection timed out) while connecting to upstream, client: x.x.x.x, server: Testtemp.com, request: "GET /phpnuke-5.4/moin_static186/classic/css/projection.css HTTP/1.1", upstream: "http://x.x.x.x:80/phpnuke-5.4/moin_static186/classic/css/projection.css", host: "x.x.x.x"

-------------------------------------------------------------------------------------------------------------------------------

Any suggestions in the nginx configuration to remediate this issue will be greatly appreciated.

Thanks in advance.