Automounting NFS share in OS X into /Volumes

osx_automount_nfs.md

I have spent quite a bit of time figuring out automounts of NFS shares in OS X...

Somewhere along the line, Apple decided allowing mounts directly into /Volumes should not be possible:

/etc/auto_master (see last line):

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

/etc/auto_nfs (this is all one line):

/Volumes/my_mount    -fstype=nfs,noowners,nolockd,noresvport,hard,bg,intr,rw,tcp,nfc nfs://192.168.1.1:/exports/my_share

Make sure you:

sudo chmod 644 /etc/auto_nfs

Otherwise the automounter will not be able to read the config and fail with a ... parse_entry: getmapent for map failed... error in /var/log/messages

This will not work (anymore!) though it "should".

$ sudo automount -cv
...
automount: /Volumes/my_mount: mountpoint unavailable

Note that, if you manually create the mount point using mkdir, it will mount. But, upon restart, OS X removes the mount point, and automounting will fail.

What's the solution?

It's so easy my jaw dropped when I figured it out. Basically, we trick OS X into thinking we're mounting somewhere else.

When you're talking about paths in just about any environment, the root folder is the highest path you can reach, whether it's C:\ (windows) or / (*nix)

When you're at this path, attempting to reach the parent path, via .. will keep you at the root path.

For example: /../../../../ is still just /

By now, a few of you have already figured it out.

TL;DR / Solution:

Change your /etc/auto_nfs config from (this is all one line):

/Volumes/my_mount    -fstype=nfs,noowners,nolockd,noresvport,hard,bg,intr,rw,tcp,nfc nfs://192.168.1.1:/exports/my_share

For pre-Catalina: To (this is all one line)

/../Volumes/my_mount    -fstype=nfs,noowners,nolockd,noresvport,hard,bg,intr,rw,tcp,nfc nfs://192.168.1.1:/exports/my_share

For Catalina and up: To (this is all one line)

/System/Volumes/Data/../Data/Volumes/my_mount    -fstype=nfs,noowners,nolockd,noresvport,hard,bg,intr,rw,tcp,nfc nfs://192.168.1.1:/exports/my_share

And re-run the automounter:

$ sudo automount -cv
...
automount: /Volumes/my_mount: mounted

..... there you go! Technically /../Volumes is still /Volumes, but the automounter does not see things that way ;)

This configuration persists the mount across restarts, and creates the mountpoint automatically.

I KNOW, RIGHT?

Feel free to send me large checks and/or high five the screen. hitmeup@l422y.com

Yes, it continues to work on Tahoe 26.3 (i.e. the latest macOS at time of authorship).