man page mmchnode:
--cnfs-interface=ip_address_list A comma-separated list of host names or IP addresses to be used for GPFS cluster NFS serving. The specified IP addresses can be real or virtual (aliased). These addresses must be configured to be static (not DHCP) and to not start at boot time. The GPFS daemon interface for the node cannot be a part of the list of CNFS IP addresses. If the keyword DEFAULT is specified, the CNFS IP address list is removed and the node is no longer conâassword. For additional information, refer to "Implementing a clustered NFS using GPFS on Linux" in the GPFS: Advanced Administration Guide.