In my experience, Nginx returns 502 when the upstream server (Unicorn in your case) doesn't respond or terminates the connection unexpectedly.
_Nik On 3/19/2013 1:29 PM, fastcatch wrote: > I have an application behind nginx (Rails on Unicorn if it matters) which > listens on a UNIX socket. > > It all works nice, especially when load is low. When there is some load on > the server though (say 70%), I randomly(?) get a bunch of 502 responses -- > usually in batches. > > Thus the question: when (under what conditions) does nginx send a 502 > response? > > Thanks in advance, > > fastcatch > > PS: The app's worker processes do not seem to be irresponsive, slow, blocked > for IO or anything else I have been able to identify as a possible cause. > Thus I want to understand more the nginx side so as to find the root cause > -- which I believe is on the other side (or some config tweak needed > soemwhere). > > Posted at Nginx Forum: > http://forum.nginx.org/read.php?2,237573,237573#msg-237573 > > _______________________________________________ > nginx mailing list > [email protected] > http://mailman.nginx.org/mailman/listinfo/nginx _______________________________________________ nginx mailing list [email protected] http://mailman.nginx.org/mailman/listinfo/nginx
