IdP is the SAML Identity Provider of OpenMOOC based on simpleSAMLphp, it takes care of the user registration/authentication process.
Before install the rpm, configure your hostname (the rpm creates a nginx file configuration based on it).
# yum install openmooc-idp-nginx
This will install a simpleSAMLphp instance and all the required dependencies for OpenMOOC, including the userregistration module, a ldap, a theme a working nginx, etc.