This enumerated value reports whether this specific fabric interconnect is currently acting as the primary (leader) or subordinate in its HA cluster pair. An admin needs cucsMgmtEntityLeadership because UCS Manager's active management session, and any configuration pushes, are only accepted through whichever fabric interconnect currently holds this 'primary' role — sending a change to the subordinate side would be rejected. A value of 'primary' on fabric interconnect B (rather than the usually-primary A) would tell an admin a failover has already occurred.