With Windows Server 2008 the product key management has changed over Windows Server 2003 and the default grace period to do the activation is 30 days.
This is too few for an full evaluation of a cluster, but this period can be reset up to 3 times extending the overall evaluation period to 120 days.
The c:\windows\system32\slmgr.vbs script allows you to check the status of this period as well as to reset it.
To display detailed license information enter this command :
C:>cscript c:\windows\system32\slmgr.vbs -dlv
To reset the grace period enter this command :
C:>cscript c:\windows\system32\slmgr.vbs -rearm
C:>shutdown -r -f -t 5
So on a cluster these commands can be executed with clusrun over all nodes in only one line.
Enjoy your Beta 1 experience,
Xavier Pillons | Principal Program Manager