We are facing a problem with inconsistent 502 errors and tracking down the reasons has been a very frustrating exercise. We can reproduce the problem by sending several simultaneous requests quickly. The problem is that several is only in the range of 10 to 20 within a 5 seconds (not a typo). So clearly this type of load should be handled easily.

We really like the Nginx + Tornado approach but are considering going to a more traditional (e.g. threading) approach because this problem has been very difficult to solve. I was wondering if you a) know how to fix this issue and b) how we can tracked down the culprit(s).

The log files simply identify there being a connection refused. We have the same problem as this post: How do I debug a HTTP 502 error?

But there is no answer provided on how to solve the problem so I'm hoping you can help because this may be a common issue with this type of setup.

Thanks in advance,

Paul