In order for ACM to import *ks clusters, a pull secret needs to be defined in order for the Klusterlet and add-ons to be able to pull images from the RH registry. 

Given that the registration service is made up of multi-tenant ACM hub clusters, we need to determine (for security reasons) if we need to define separate pull secrets for each tenant; or if the global pull secret across all tenants is accetable.

—

The pull secret can be configured for *ks in two different ways:

Defining a the pull secret in the MultiClusterHub CR:
https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.5/html/install/installing#custom-image-pull-secret

OR

Using the ManagedClusterImageRegistry to define separate image registeries in a ManagedClusterSet:
https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.5/html/clusters/managing-your-clusters#imp-clust-custom-image-override