The first step in adding vCenter topology to VMTurbo Operations Manager (OpsMan) is adding your vCenter target(s) in the Admin -> Target Configuration screen within OpsMan. When adding a target, you are prompted for the IP/hostname and credentials to allow OpsMan to successfully access the target, discover and subsequently manage the topology.
The question comes up often, of "how do i remove hosts or clusters from being managed?" or "how do I limit OpsMan to managing only a subset of my vCenter topology?" Also, you could have purchased a limited number of socket licenses and are getting the "Exceeded socket limit" alert at the bottom of the UI.
To limit the management scope of your environment from within OpsMan, you need to limit the permissions within vCenter for the service account you're using to add the target to OpsMan.
The simplest and most ideal way to do this is to set the Admin permissions for the service account at the Datacenter level and propagate them down because within vCenter, the Datacenter object includes all the Hosts/Clusters, VM's, vSwitches/dvSwitches, and Datastores that are needed to be properly discovered and managed by OpsMan.
If you choose set the permissions at a level below the Datacenter, you will need to ensure that permissions are given to the Cluster(s), Network(s) and also ALL Datastores that every host in the cluster have access to. NOTE: You CANNOT set the permissions at the Host level. The lowest level you can go is at the Cluster level.
After you set the vCenter permissions properly, you can go into Admin -> Target Configuration and click on Rediscover.