[TriLUG] NFS and idmapd

[Brian via TriLUG]

Hi y'all,

As I gradually reinstate the less-critical services of the server I 
rebuilt with CentOS 7 recently, I was hoping to eschew samba in favor of 
NFS for sharing between Linux hosts.  Problem is, I can't get id mapping 
to work.  I'm certain I'm just missing some critical piece or getting 
the order of operations wrong, but here's what's going on:

- Server: CentOS 7.  User "brian"'s id is 500
- Client: Debian Jessie (8.4).  User "brian"'s id is 1000

I can mount the NFS export on the client, but the id mapping isn't 
happening; when I do an "ls -l" I see "500 500" as the ownership instead 
of "brian brian"

I've been googling around and what I've read so far is that if the 
services are configured correctly, name-to-id mapping should happen sort 
of automagically.  I've done:

echo N > /sys/module/nfs[d]/parameters/nfs4_disable_idmapping

on both client and server (server with "d" in path, client without)

I've done nfsidmap -c on both sides

Obviously I'm missing something...but what?

Thanks in advance,
-Brian