Details
http://pubs.vmware.com/vsphere-51/topic/com.vmware.vsphere.update_manager.doc/GUID-EF6BEE4C-4583-4A8C-81B9-5B074CA2E272.html
Solution
Leverage the VMware Update Manager to test and apply patches as they become available.
Impact-VMs must be powered off in order to update the host ESXi server.
Supportive Information
The following resource is also helpful.
This control applies to the following type of system VMware.