How to debug Nginx random 500 responses?

How to debug Nginx random 500 responses?

References

Reference NO 1

http://www.linuxine.com/story/how-debug-nginx-random-500-responses

Reference NO 2

http://serverfault.com/questions/317454/nginx-how-do-i-track-down-a-random-500-from-nginx-not-my-application-potenti

Reference NO 3

https://forum.linode.com/viewtopic.php?p=58216&sid=6839bcd03c224ef19fc4a54e89d078c4

Reference NO 4

https://www.ruby-forum.com/topic/202023

Reference NO 5

http://forum.nginx.org/read.php?2,235763,235763

Reference NO 6

http://stackoverflow.com/questions/17631919/unhandled-exception-in-django

Reference NO 7

http://www.bailopan.net/blog/?p=855

Reference NO 8

http://www.tornadoweb.org/en/stable/overview.html