Nginx 502 Bad Gateway

This morning I awoke to a 502 Bad Gateway error from Nginx. Luckily it was only one user that made me aware of this! The current setup I'm running is Nginx as a proxy for Apache.

To resolve this, I first checked to see if httpd was running. Surprisingly, httpd was not running. I went ahead and did "service httpd restart" and all was good. 

After fixing the issue, I set out to see why it may not have been running. The issue was caused by the httpd being set to stop at boot time. I fixed this by using "chkconfig httpd on" which set it to start at boot time. Also accomplished with "sudo /sbin/chkconfig --add httpd"