By default NFS server reports as scope and owner major the host UUID value and zero for owner minor. It works good in case of standalone server. But in case of CARP-based HA cluster failover the values should remain persistent, otherwise some clients like VMware ESXi get confused by the change and fail to reconnect automatically.
The patch makes server scope, major owner and minor owner values configurable via sysctls. If not set (by default) the host UUID value is used.