I am not maintaining this repository anymore. You can find up-to-date version of nexus cartridge here https://github.com/juliogonzalez/sonatype-nexus-openshift

This git repository will help you get up and running quickly with nexus running on tomcat on OpenShift.

Create an account at http://openshift.redhat.com/ , don't forget to create a namespace and install client tools as well.

Create a DIY application

rhc app create -a nexus -t diy-0.1

Grab this quickstart codes and make it working for you!

cd nexus
git remote add nexus git://github.com/shekhargulati/nexus.git
git pull -s recursive -X theirs nexus master
git push

That's it, you can now checkout your nexus at:

http://nexus-$yournamespace.rhcloud.com/nexus

The default nexus user is admin/admin123

Note: You can get the latest nexus code from github at https://github.com/sonatype/nexus-oss