To use a contextualized CernVM :

• Login here (or register) and create a context https://cernvm-online.cern.ch/dashboard/
• Go to your context and copy the uuid (https://cernvm-online.cern.ch/context/view/[...])
• Create a cernvm instance in openstack and set the following user data (in post-creation, user data)

[amiconfig]
plugins=cernvm

[cernvm]
contextualization_key=<uuid>