HAProxy random HTTP 503 errors

Question

We\'ve setup 3 servers:

• Server A with Nginx + HAproxy to perform load balancing
• backend server B
• backend server C

Here is our

Answer 1

Adding my answer here for anyone else who encounters this exact same problem but none of the listed solutions above are applicable. Please note that my answer does not apply to the original code listed above.

For anyone else who may have this problem, check your config and see if you might have mistakenly put the same "bind" line in multiple sections of your config. Haproxy does not check this during startup, and I plan to submit this as a recommended validation check to the developers. In my case, I have 3 different sections of the config, and I mistakenly put the same IP binding in two different places. It was about a 50/50 shot on whether or not the correct section would be used or the incorrect section was used. Even when the correct section was used, about half of the requests still got a 503.