Bug#800133: systemd: Jessie won't boot if a filesystem in /etc/fstab is missing

[Vasudev Kamath]

Ritesh Raj Sarraf <rrs at debian.org> writes:

> On Sun, 2015-09-27 at 11:18 +0200, folco wrote:
>> Package: systemd
>> Version: 215-17+deb8u2
>> Severity: normal
>> 
>> Dear Maintainer,
>> 
>> You closed the bug #797039 without solving it.
>> Here is the link: 
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=797039
>> 
>> So please, don't say that there is no bug before closing the report.
>> 
>> I tried to solve it myself in several ways, but I always get one of
>> these three
>> problems :
>> - the system boots in emergency mode
>> - the system has an invalid /etc/fstab
>> - systemd hangs 90 seconds because it doesn't find my partition
>
>
> In the last local meetup, I had another user (Vausdev) run into the
> very same problem.
>
> The problem was his incorrect entry in /etc/fstab, which led to an
> incomplete boot, giving an impression that systemd was at fault. :-)
>
> In his case, it was not just a 90 seconds hang. The system would only
> boot in emergency mode.
>
>
> After fixing his fstab, everything was normal again.
>
> From that meetup, after root causing his bug, it was a clear impression
> that it was difficult to debug such boot issues. From just the console
> scrolls, it wouldn't have been possible. So I think there may be some
> room for improvement here.
>
> The reason might be the massive parallelization of services by systemd.
> Because from those logs, for a user, it would be nearly impossible to
> correlate the failure. Ofcourse, if the emergency shell can provide the
> full journal access (I don't recollect if I tried that then), an
> experienced systemd user should be able to dive into the logs.

In my case the emergency shell was never giving prompt after logging in
so it was of no use at all. Only way to get into emergency shell using
systemd.unit=emergency.target but there was no indication it was faulty
fstab entry which was causing error. My LVM home partition was not
activated at all.

RRS found weird entry in my fstab which had mount option
x-systemd.automount, I was also not sure why I put it there but removal
of that option made system boot again. So giving more hints and debug
entries on what really went wrong during boot could improve usability of
systemd a lot.