overlayroot prevents shutdown / reboot under nfsroot

[Michał Sawicz]

Hey, I'm using nfsroot and as long as I don't overlay it, it will shutdown / reboot just fine.

As soon as I put tmpfs as an overlay, the system will hang on shutdown / reboot.

I'd love to add more detail (like some debug log - but all logging seems to stop before the hang), please point me anywhere I could read about debugging shutdown issues.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Sean Bright (sbright)]

Same symptoms as Michal and same inability to capture logs. This is fairly critical for me, how can I help move this forward?

[Sean Bright (sbright)]

Just messing around trying to get this to work. if I remove the eth0 stanzas (auto eth0... iface eth0...) from /etc/network/interfaces, I am able to shutdown with nfsroot + overlayrootfs.

[Sean Bright (sbright)]

Turns out that the /etc/network/interfaces stuff I mentioned before was a red herring, here is the actual problem.

Without overlayroot the (nfs) root filesystem is mounted at /, and on reboot/shutdown /etc/init.d/umountnfs.sh will skip that mount point when unmounting the network file systems (because of lines 49 & 50 of /etc/init.d/umountnfs.sh).

With overlayroot enabled, the "root" filesystem is mounted at /, but the nfs mount that is "under" the overlay is mounted at /media/root-ro, which is NOT skipped during reboot/shutdown.

The fix I have in place is to change line 49 of /etc/init.d/umountnfs.sh from:

    /|/proc|/dev|/dev/pts|/dev/shm|/proc/*|/sys|/run|/run/*)

to:

    /|/proc|/dev|/dev/pts|/dev/shm|/proc/*|/sys|/run|/run/*|/media/root-ro)

And I am able to reboot/shutdown properly.

[Sean Bright (sbright)]

Also, anyone looking to debug shutdown issues should do three things:

Set up a serial console on the affected machine by adding (there is a lot of documentation out there on how to do this)

Add --verbose to the kernel parameters (the APPEND line if you are PXE booting)
Change.

Change VERBOSE to 'yes' in /lib/init/vars.sh

That is how I was able to work out what was going on.

[Scott Moser (smoser)]

Hi, Is this still relevant with 16.04 or 18.04 ?

[Launchpad Janitor (janitor)]

[Expired for cloud-initramfs-tools (Ubuntu) because there has been no activity for 60 days.]