I think it is a bit confusing to have "lctl nodemap add" create a new nodemap, and then "nodemap add_range" and "nodemap add_offset" to modify the nodemap. For OST Pools, the commands are "lctl pool new" and "lctl pool add", which gives a better distinction between the two operations IMHO.

I think it would be useful to add an alias "nodemap new" that is equivalent to "nodemap add" and start documenting this as the preferred command (keeping "nodemap add" for compatibility.