auto-mount NFS shares on boot

[Jonas Meurer <jonas@freesources.org>]

Hello,

I fail to configure my Debian/Jessie server system in a way that the
NFS mounts are mounted automatically on boot.

Problem seems to be that the NFS mounts are mounted directly after
the root fs, before the network is set up properly. Also, the mountnfs
if-up.d hook from /etc/network/if-up.d/mountnfs doesn't work for
systemd systems.

Here's the relevant output from the boot console:

> [FAILED] Failed to mount /var/vmail.
> See 'systemctl status var-vmail.mount' for details.
> [DEPEND] Dependency failed for Remote File Systems.
>          Starting Trigger Flushing of Journal to Persistent Storage...
>          Starting LSB: Prepare console...

And 'systemctl status var-vmail.mount' reveils:

> Process: 352 ExecMount=/bin/mount -n nfs1.freesources.org:/vmail
>             /var/vmail -t nfs4 -o sec=krb5i,bg (code=exited, status=32)

While searching the web I learned that Ubuntu and Redhat based distros
seem to support the '_netdev' option to entries in /etc/fstab for such
cases, but it seems like Debian doesn't support this option, right?

Is there any other solution to mount NFS shares during boot process on
Debian Jessie systems? Mounting the manually (or by rc.local) later is
not an option for me. Several service daemons that start later in the
boot process depend on the NFS shares being mounted.

Cheers,
 jonas