[ubuntu 16.10] nfs fstab entry fails to mount on boot

[zach]

Impact: NFS shares listed in /etc/fstab do not mount on boot.

During booting, it appears that the nfs share attempts to mount before the network allows for name resolution (see errors below). However, the systemd dependencies clearly show a requirement for network-online.target (see below). After booting, shares can be mounted fine via mount -a.

Regression potential: This same issue appears to have been addressed in LP: #1515446 but I observe the problem on a fresh install of kubuntu 16.10.

Configuration and error logs:

> tail -2 /etc/fstab
# nfs mounts
zpl-scope:/mnt/scopearray /mnt/scopearray nfs noatime,intr 0 2

> systemctl status mnt-scopearray.mount
● mnt-scopearray.mount - /mnt/scopearray
   Loaded: loaded (/etc/fstab; generated; vendor preset: enabled)
   Active: failed (Result: exit-code) since Wed 2016-11-16 15:47:07 CST; 45min ago
    Where: /mnt/scopearray
     What: zpl-scope:/mnt/scopearray
     Docs: man:fstab(5)
           man:systemd-fstab-generator(8)

Nov 16 15:47:07 zpl-purple systemd[1]: Mounting /mnt/scopearray...
Nov 16 15:47:07 zpl-purple mount[1406]: mount.nfs: Failed to resolve server zpl-scope: Name or ser
Nov 16 15:47:07 zpl-purple systemd[1]: mnt-scopearray.mount: Mount process exited, code=exited sta
Nov 16 15:47:07 zpl-purple systemd[1]: Failed to mount /mnt/scopearray.
Nov 16 15:47:07 zpl-purple systemd[1]: mnt-scopearray.mount: Unit entered failed state.

> systemctl list-dependencies mnt-scopearray.mount
mnt-scopearray.mount
● ├─-.mount
● ├─system.slice
● └─network-online.target
● ├─networking.service
● └─NetworkManager-wait-online.service

> lsb_release -rd
Description: Ubuntu 16.10
Release: 16.10

> apt-cache policy network-manager
network-manager:
  Installed: 1.2.4-0ubuntu1
  Candidate: 1.2.4-0ubuntu1
  Version table:
 *** 1.2.4-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu yakkety/main amd64 Packages
        100 /var/lib/dpkg/status

> apt-cache policy nfs-common
nfs-common:
  Installed: 1:1.2.8-9.2ubuntu1
  Candidate: 1:1.2.8-9.2ubuntu1
  Version table:
 *** 1:1.2.8-9.2ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu yakkety/main amd64 Packages
        100 /var/lib/dpkg/status

Mitigation / workaround: Adding 'x-systemd.automount' to the fstab options fixes this.