NFS shares fail to mount from Ubuntu server [UPDATE]

Troubleshooting
1

I have googled pretty much everything related to NFS shares. The service is up and running, the shares are exported (verified via showmount -e), and unless I’m completely mistaken in how the exports should be addressed, the shares are exported to the proper IP addresses.

Here’s my /etc/exports file:

/export/home_shared 192.168.1.1/255.255.255.0(rw,sync,insecure) 192.168.1.3(rw,no_root_squash)
/export/xen_vhd 192.168.1.1/29(rw,sync,insecure) 192.168.1.2(rw,no_root_squash)

It’s my understanding the IP/netmask filters allowed clients, and as far as I know the combination should allow home_shared to be accessible from all clients in the 192.168.1.* range, and the xen_vhd share should be accessible from all clients in the 192.168.1.[1-7] range.

From my Ubuntu 14.04 server (IP 192.168.1.3), I can’t mount the share home_shared with the error:

mount.nfs: access denied by server while mounting 192.168.1.25:/export/home_shared.

However, from my XenServer (192.168.1.2) I was able to mount the xen_vhd share and have complete access.

I don’t know if this in an Ubuntu issue or Rockstor issue. Both Xen and Ubuntu are using NFSv4.

Been banging my head against this one for days. Any suggestions?

TIA,
Josh

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EDIT: Apparently I can’t edit my own posts, so I’m replying instead. Here’s an update for anyone interested.

I was able to get Ubuntu to attach an NFS share R/W using the ‘-o vers=3’ option. However, this isn’t really desirable, as security in vers3 leaves much to be desired. So I kept trying other things.

It turns out, Rockstor uses NFSv4 by default, but fails to export a root directory.

Adding the line:

/export 192.168.1.0/24(rw,fsid=0,no_subtree_check,sync)

fixed the problem. Any client in the subnet can access the /export/home_shared directory by using:

sudo mount -t nfs 192.168.1.25:/home_shared /mnt

Note with NFSv4 you don’t explicitly specify the root (fsid=0) directory. Creating files and folders result in uid=nobody and gid=nogroup, which is correct for v4 while using root credentials (required for mounting without fstab user entry).

This issue appears to be solved. I changed the tag to [UPDATE] to see if anyone has anything to suggest in the event I missed anything I could have done different. Or to suggest adding NFS shares via Rockstor web interface add the fsid=0 export and change the tooltip to reflect NFSv4 conventions.

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