Binary package hint: upstart
Yesterday I rebooted my Lucid server and /var had errors which had to be manually resolved, but because I didn't use 'splash quiet' on the kernel command line (so I can see boot messages), there was no message to 'S' (skip) or 'M' (maunually recover) /var. More importantly, I could not reboot the machine without /var mounted. On this machine, I ultimately had to use a recovery CD to fsck /var manually.
Trying to reproduce this in a VM, I found that:
a) 'splash' must be present for fsck feedback, but you lose boot messages
b) booting without 'splash quiet' gives boot messages, but no fsck feedback. You can remember to enter 'm' in case of problems to enter a maintenance shell (not discoverable)
b) disabling plymouth by booting with 'init=/sbin/init noplymouth' provides no way to get at the maintenance shell. tty7 only shows: "plymouthd: ply-keyboard.c:384: ply_keyboard_watch_for_input: Assertion `keyboard != ((void *)0)' failed."
I filed this against upstart because:
1. mountall shouldn't interminably hang when /var is not present (which is possible on systems with /var on a separate partition, as on mine)
2. when booting without 'splash', something should make it discoverable that 'm' can be pressed to enter a maintenance shell
3. upstart in Ubuntu should be able to handle 'noplymouth' and give some way to enter the maintenance shell
If this assessment is in error, please refile.