You can via a user, but we don't support that.  The issue lies with if you only have a VM, then you miss potential issues with the host.  If you only have a few hosts, it might miss part of a cluster or someting else using the storage...  There are lots of cases where not having all the data could cause issues, so we only support all of a vCenter.
Hi,  Could i check if it is possible to select specified ESX host or Virtual Machines to monitor instead of pulling all VM and hosts into Foglight? Thanks.  Regards, Jamie.
Monitoring selected VM, ESX Hosts, Clusters