I have a recipe for EGI sites that already have CVMFS installed. They go like this:
1. Install the RPM cvmfs-x509-helper on every worker node
2. mount the repository /cvmfs/ligo.osgstorage.org
3. Create config file /etc/cvmfs/config.d/ligo.osgstorage.org.conf
With following contents:
4. Install on every compute node IGTF IOTA (which has the CILogon Basic cert bundle), ca_policy_igtf-iota
think we should have them widespread documented.