问题
Myself and my users are often running into a Cloudflare Bad Gateway 502 error. Trying to figure out what goes wrong is hard, because Cloudflare blames the hosting company and the hosting company blames Cloudflare. A typical situation when using Cloudflare.
What I noticed is that nothing actually fails. The host receives the request and is handling the request just fine but which sometimes takes a bit longer than usual to complete. But Cloudflare can't wait and instead throws a Bad Gateway error, while the script is actually still running.
I've noticed this behavior when performing heavy back-end tasks (like generating +50 PDFs). My users notice this when they try to upload an image (which often starts a re-sizing task).
Is there a way I can configure my server so that Cloudflare knows that the request is still being processed? Or should I just ditch Cloudflare overall?
回答1:
The culprit was Railgun. After disabling Railgun (in Cloudflare's control panel) the Bad Gateway 502 errors immediately disappeared.
来源：https://stackoverflow.com/questions/33741777/cloudflare-bad-gateway-502-error