This git repository helps you get up and running quickly w/ a Joomla installation on OpenShift. The backend database is MySQL and the database name is the same as your application name (using $_ENV['OPENSHIFT_APP_NAME']). You can name your application whatever you want. However, the name of the database will always match the application so you might have to update .openshift/action_hooks/build.

Create an account at http:https://openshift.redhat.com/

Create a php-5.3 application (you can call your application whatever you want)

rhc app create -a joomla -t php-5.3

Add MySQL support to your application

rhc cartridge add -a joomla -c mysql-5.1

Add this upstream Joomla repo

cd joomla
git remote add upstream -m master git:https://github.com/openshift/joomla-example.git
git pull -s recursive -X theirs upstream master
# note that the git pull above can be used later to pull updates to Joomla

Then push the repo upstream

git push

That's it, you can now checkout your application at (default admin account is admin/4dm1n):

http:https://joomla-$yournamespace.rhcloud.com

NOTES:

GIT_ROOT/.openshift/action_hooks/deploy: This script is executed with every 'git push'. Feel free to modify this script to learn how to use it to your advantage. By default, this script will create the database tables that this example uses.

If you need to modify the schema, you could create a file 
GIT_ROOT/.openshift/action_hooks/alter.sql and then use
GIT_ROOT/.openshift/action_hooks/deploy to execute that script (make sure to
back up your application + database w/ 'rhc app snapshot save' first :) )