Please see this post for details of the Samba4 and NFS installation on Ubuntu. The current post uses the client server details from there.
We have to change the export slightly to get the automount to recognise the domain entry, CACTUS in this case, so we must export it.
please be careful with line breaks if you are copying from here. I'll convert the text so that it fits onto a single line but I can only guarantee that in my browser (Chromium under LXDE on openSUSE)
sudo apt-get install autofs
* -rw,sec=krb5,vers=3 /home/CACTUS/&
Finally, restart the automounter:
service autofs restart
Same as Ubuntu except that it's already installed and to restart it's: