When attempting to install an SQL Server 2008 R2 cluster on Windows Server 2012 R2 you may receive the error message “The sql server failover cluster services is not online” when running setup on the first node.
If you are certain that your cluster is running at the windows level and appears healthy then your issue could be that a deprecated feature of Windows Clustering has not been installed by default under Windows Server 2012. SQL Server 2008 Failover Clusters seem to depend on this feature.
To remedy the situation open an elevated powershell window and run:
Install-WindowsFeature -Name RSAT-Clustering-AutomationServer
More information can be found here: http://blogs.msdn.com/b/clustering/archive/2012/04/06/10291601.aspx