[Bug 1755863] Re: netbooting the bionic live CD over NFS goes straight to maintenance mode :

[Woodrow Shen]

I keep doing some experiments (with Dell/HP laptops) and there are some
conclusions currently:

1. why does the issue happen (not real root cause)
Due to local-fs.target, the fstab-generator automatically adds dependencies of type Before= to all mount units that refer to local mount points for this target unit. In addition, it adds dependencies of type Wants= to this target unit for those mounts listed in /etc/fstab that have the auto mount option set[1].
Therefore, the emergency shell is triggered by local-fs.target which is dependent on failures of several systemd mounts.

2. provides 2 approaches for workaround fix

1) append "systemd.mask=dev-hugepages.mount systemd.mask=dev-
mqueue.mount systemd.mask=sys-fs-fuse-connections.mount systemd.mask
=sys-kernel-config.mount systemd.mask=sys-kernel-debug.mount
systemd.mask=tmp.mount" into kernel boot options.

2) add "toram" into kernel boot options.
it would completely decompress the filesystem into RAM, which requires 3-4x more RAM, and is hence undesired[2].

3. trade-off between workarounds
Until we find the solution, the better way to workaround is to use "toram" to fix the issue. The reason behind it is we not only get speed-up the installation but also avoid the unstable network with nfs, despite requiring more RAM.

4. The real solution concern
I think the solution may be more complicated if we really want to fix, and ideally we have to consider the cases of normal (e.g. from usb stick) and nfs mount to satisfy the conditions to avoid systemd failure with dependencies or protocol.

[1] https://www.freedesktop.org/software/systemd/man/systemd.special.html
[2] https://wiki.ubuntu.com/BootToRAM

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https://bugs.launchpad.net/bugs/1755863

Title:
  netbooting the bionic live CD over NFS goes straight to maintenance
  mode :

Status in casper package in Ubuntu:
  Confirmed
Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  netbooting the bionic live CD[1] over NFS goes straight to maintenance
  mode :

  [1] http://cdimage.ubuntu.com/daily-live/current/

  # casper.log
  Begin: Adding live session user... ... dbus-daemon[568]: [session uid=999 pid=568] Activating service name='org.gtk.vfs.Daemon' requested by ':1.0' (uid=999 pid=569 comm="" label="unconfined")
  dbus-daemon[568]: [session uid=999 pid=568] Successfully activated service 'org.gtk.vfs.Daemon'
  dbus-daemon[568]: [session uid=999 pid=568] Activating service name='org.gtk.vfs.Metadata' requested by ':1.0' (uid=999 pid=569 comm="" label="unconfined")
  fuse: device not found, try 'modprobe fuse' first
  dbus-daemon[568]: [session uid=999 pid=568] Successfully activated service 'org.gtk.vfs.Metadata'

  (gvfsd-metadata:580): GUdev-CRITICAL **: 16:28:56.270:
  g_udev_device_has_property: assertion 'G_UDEV_IS_DEVICE (device)'
  failed

  (gvfsd-metadata:580): GUdev-CRITICAL **: 16:28:56.270: g_udev_device_has_property: assertion 'G_UDEV_IS_DEVICE (device)' failed
  A connection to the bus can't be made
  done.
  Begin: Setting up init... ... done.

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