Register vCloud Director with Shared SSO to which all backing resource vCenter Servers are registered.

Procedure

Register VCD with the lookup service of the tenant VC through REST API.
PUT https://<vcd ip>:<port>/api/admin/extension/settings/lookupService  
Accept: application/*+xml;version=6.0 
Content-Type: application/*+xml;version=6.0  
<LookupServiceParams xmlns="http://www.vmware.com/vcloud/extension/v1.5" 
xmlns:vcloud_v1.5="http://www.vmware.com/vcloud/v1.5" 
userName="SSO_ADMIN_USER" password="SSO_ADMIN_USER_PASS"><LookupServiceUrl>https://{SSO_URL_IP}:{SSO_PORT}/lookupservice/sdk</LookupServiceUrl>     
</LookupServiceParams>
Note:

Here onwards vCloud Director can be accessed only with this URL https://VCD IP or hostname/cloud/login.jsp.

Enable SSO in vCloud Director UI: Administration > Federation > Use vSphere Single Sign On