Installing vSphere Update Manager
The Update Manager was used to patch both the ESXi hosts and VM Guest Operating Systems. Starting with the Update Manager 5.x, patching VM Guest Operating Systems is no longer supported. The Update Manager can be installed on the same machine running vCenter Server. The Update Manager 5.1 can only be installed on a 64-bit machine.
Here are the compatible operating systems:
Windows 2003, Windows 2003 R2 [all 64-bit and SP 2 is a requirement]
Windows 2008, Windows 2008 SP2, Windows 2008 R2, Windows R2 SP1 [all 64-bit]
Note
With the release of vSphere Update Manager 5.1—Update1 on 25-April-2013, VMware have added support for Windows Server 2012 64-bit. For further details, visit the following link:
http://www.vmware.com/support/vsphere5/doc/vsphere-update-manager-51u1-release-notes.html
You need the following information handy in order to install vSphere Update Manager:
The vCenter Server's IP address or FQDN
The vCenter Server's administrator username and password...