¶
Issue since Ubuntu 22.04 LTS !The NFS export option 'crossmnt' in
/etc/exportscausing problems like hanging on NFS-clients
and the NFS-service being corrupted which need a restart.
The option is needed for server made mounts to transparent for clients.
This issue was not apparent in Ubuntu 20.04 LTS before the upgrade to v22.04.
Maybe it is an issue which a fresh installation does not have and should be investigated.
Some packages are needed for allowing this NFS configuration server setup.
apt install nfs-kernel-server bindfs
Enable file locking on NFS shares by enabling the rpc-statd service and starting it.
systemctl enable rpc-statd
systemctl start rpc-statd
Edit file /etc/exports and fill in the exports.
In this example only the root is exposed where all binds will reside eventually.
/srv/nfs *.fritz.box(rw,fsid=root,insecure,crossmnt,no_subtree_check,async)
Call exportfs -r to make the changes happen.
Check if the exports are there using showmount -e local or remote showmount -e <server-ip-name>.
Do not forget to create the needed mount points in /srv/nfs/.
Temporary mount.
mount --bind /mnt/ntfs-avmedia /srv/nfs/avmedia
mount --bind /mnt/user-data /srv/nfs/userdata
For reboot proof mounting.
# Bind mounts for NFS
/mnt/user-data/<user> /srv/nfs/userdata none defaults,bind 0 0
/mnt/ntfs-avmedia /srv/nfs/avmedia none defaults,bind 0 0
This package is required for the client side and must be installed.
apt install nfs-common
As root user mount the exported directory using the command line.
Or edit the fstab file to make it happen when the system boots.
Where <server-ip-name> is the actual IP or hostname.
mount -t nfs <server-ip-name>:/srv/nfs /mnt/server
Edit file /etc/fstab and append the following.
# Mount NFS server using v3
<server-ip-name>:/srv/nfs /mnt/server nfs defaults,proto=tcp,mountproto=udp,x-systemd.device-timeout=3s,_netdev 0 0
# Mount NFS server using v4 (Note: offset '/srv/nfs` is not applicable here)
<server-ip-name>:/ /mnt/server nfs4 defaults,proto=tcp,x-systemd.device-timeout=3s,_netdev 0 0
Since the 22.04 LTS problem with exporting bindfs mounts as NFS mounts the following is replacing the previous.
<server-ip-name>:/mnt/user-data/arjan /mnt/server/userdata nfs4 x-systemd.automount,x-systemd.requires=network-online.target,proto=tcp,x-systemd.device-timeout=6s,_netdev,vers=4,nofail 0 0
<server-ip-name>:/mnt/avmedia /mnt/server/avmedia nfs4 x-systemd.automount,x-systemd.requires=network-online.target,proto=tcp,x-systemd.device-timeout=6s,_netdev,vers=4,nofail 0 0
# Overlay-FS for Windows QT adapted for Linux usage.
none /mnt/server/userdata/applications/linux/QtWin overlay x-systemd.requires=/mnt/server/userdata,ro,_netdev,relatime,lowerdir=/mnt/server/userdata/applications/windows/Qt,upperdir=/mnt/server/userdata/applications/linux/QtWin-overlay/upper,workdir=/mnt/server/userdata/applications/linux/QtWin-overlay/work,redirect_dir=nofollow,nouserxattr 0 0
At the moment of writing the all mounts over the network when using ipv6 hangs
when waking from a system sleep on Ubuntu 22.04 only so far and not on 20.04.
Optionsproto=tcp,mountproto=udpare added to prevent this.
A NFS mount does not have a reconnect option.
In order to reconnect a script is created nsf_remount
in the /lib/systemd/system-sleep directory.
#!/bin/sh
#
# Fixes nfs mount after suspension when disconnected.
#
case $1 in
pre)
;;
post)
mount /mnt/server
;;
esac