3 months ago I configured my HAproxy to balance 2 Apache webservers. Since then everything is up and running. Today I woke up seeing a HAproxy 503 error. When I checked the its web stats I saw the webservers marked as L7STS/500 (internal server error). Ironically every webserver is up and running, even the website is accessible when you browse both webserver IPs, so I really have no idea what's happening here. I even shutdown both webservers and when I browse www.myurl.com (now passing through HAproxy) I still see "503 Service Unavailable" (with webservers ON or OFF).
Not even with a restart (which occurs perfectly) this seems to get fixed.
Thanks in advance.
-- EDIT: The website uses Yii Framework. Yii has a "runtime/" directory which needs to have write permissions. The 500 error was because that directory was missing permission due to some file updates through FTP. Guess I have to work on sticky sessions in order to permanently fix this.