NGINX: upstream timed out (110: Connection timed out) while reading response header from upstream

Question

I have Puma running as the upstream app server and Riak as my background db cluster. When I send a request that map-reduces a chunk of data for about 25K users and returns i

Answer 1

I had the same problem and resulted that was an "every day" error in the rails controller. I don't know why, but on production, puma runs the error again and again causing the message:

upstream timed out (110: Connection timed out) while reading response header from upstream

Probably because Nginx tries to get the data from puma again and again.The funny thing is that the error caused the timeout message even if I'm calling a different action in the controller, so, a single typo blocks all the app.

Check your log/puma.stderr.log file to see if that is the situation.