I have been playing with OpenShift for past several hours. It looks great. But a while back I started to get 503 Internal Server error.
When I checked logs using rhc tail , I saw this error: Layer 7 Wrong Status, Invalid Response 404.
I spent an hour or so troubleshooting. Turns out the issue was Netbeans had added src/main/web/app/WEB-INF/jboss-web.xml when I ran the application locally on my machine. I committed this file, thinking I might need it. Deleting it from repo and repushing, fixed the issue.