The Sumavisor is built on top of xCAT. The Sumavisor is a rails application, with lots of xCAT plugins that sit on top of the base xCAT.  One thing we had to work out was having a web server host a rails application (the Sumavisor) and allow xCAT to install nodes via HTTP.  The solution is quit trivial thanks to my friend Ben.  You simply add one line in the directories you don’t want Passenger to run in.  So for xCAT, you put in /etc/httpd/conf.d/xcat.conf

<Directory “/tftpboot”>
Options Indexes +FollowSymLinks +Includes MultiViews
AllowOverride None
PassengerEnabled off
Order allow,deny
Allow from all
</Directory>
<Directory “/install”>
Options Indexes +FollowSymLinks +Includes MultiViews
AllowOverride None
PassengerEnabled off
Order allow,deny
Allow from all
</Directory>

That makes it so my code all runs very nice :-)