After you install the Cloud Manager Orchestration Agent on a VCenter Server, you need to associate the vsphere_client policy to a vSphere resource before the Discover VM hosts job can work.
Section 6.1, Discovering VM Hosts and Repositories
Section 6.2, Discovering VM Images
Section 6.3, Resynchronizing the VM Host’s State
Section 6.4, Shutting Down VM Hosts
Section 6.5, Restarting VM Hosts
Section 6.6, Understanding VM Host Failover