Along with Update Rollup 2 for System Center 2012 R2 (KB2932881), also Update 2 (KB2932946) for Windows Azure Pack was released. Update 2 fixes 10 known issues, amongst others a fix for the problem created with the Usage Collector in Update 1. Because WAP does not currently support rolling upgrades, it is necessary to schedule downtime for the WAP machines. Please be careful running this update in your production environment and expose them to a test environment first. There are so many components which depend on each other so take any precautions in the form of checkpoints (formerly called Hyper-V snapshots) and make sure you have recent full backups of your environment.
Although it is stated nowhere, you would be advised to first start with the System Center 2012 R2 Update Rollup 2 and run the documented SQL Scripts for VMM and SCOM first (important!) before you approve the Windows Azure Pack Update 2 installation. The SQL Script for VMM can be found in http://support.microsoft.com/kb/2932926. A reference to the path of the SQL Scripts for the SCOM OperationsManager and OperationsManagerDW databases can be found in http://support.microsoft.com/kb/2929891.