Filtering Virtual Machines
You can retrieve a list of virtual machines that match a specific filter or a group of up to one thousand virtual machines available in a specific vCenter Server instance.
You can retrieve a list of up to one thousand virtual machine IDs for a single vCenter Server instance by filtering them based on a specific requirement, such as a host, cluster, datacenter, or resource pool on which the VMs are running.
Call the list methods of the VM service to retrieve only a list of the virtual machines that match your specific criteria. The method takes as parameter the VMTypes.FilterSpec instance that you can use to describe the virtual machine filter.