Helped along greatly by http://yourmacguy.wordpress.com/2012/06/29/osx-automount/

Apple seems to change how nfs/nis/anything unix works with each release. On Snow Leopard my nis and nfs worked great, but after my upgrade to Mountain Lion, less so.

My nis already “works”. As in, ypcat passwd does what you'd expect but permissions and ownership over nfs are still buggered. I'll update this post or make a new one when I have that figured out.

Here's how I got /home to automount a Linux nfs server.

sudo mkdir /etc/automounts

# /etc/auto_master 
# Automounter master map
#
+auto_master        # Use directory service
/net            -hosts      -nobrowse,hidefromfinder,nosuid
#/home          auto_home   -nobrowse,hidefromfinder
/Network/Servers    -fstab
/-          -static

/home /etc/automounts/home

# /etc/automounts/home 
* -fstype=nfs,rw,bg,hard,intr,tcp fs.burgundywall.com:/tank/home/&

sudo automount -vc
ls /home/username

Update: I gave up and just added myself to a local group so that I can edit files on my webserver and get on with my life. Damn you apple.

# as root
dscl . create /Groups/apache gid 48 # where 48 is the group number on linux
dseditgroup -o edit -p -a kneufeld -t user apache # type in your root password
# open a new terminal window and it will have the new permissions

I have two Fedora 15 machines, they both authenticate using NIS and mount home directories via NFS. The first machine worked perfectly, the second did not. I could login via ssh (nis works) but all my file owners were nobody:users.

Anyhow, through much trial and error I learned about /etc/imapd.conf. So after booting my machine, if I restarted rpcidmapd and autofs then the file permissions were correct.

After much Googling I found this

Solution:

edit /etc/idmapd.conf
uncomment and edit Domain = <your nis domain>

If I had to guess, I think the NIS domain isn't being set until after rpc.idmapd and automount are started. That's why restarting the services later seems to work. Or whatever. Why it works on one fresh install but not the next I'll never know.