[systemd-devel] systemd unexpectedly dropping into rescue mode - how do I best debug this?

[Kay Sievers]

On Thu, Oct 4, 2012 at 12:05 PM, Ingo Molnar <mingo at kernel.org> wrote:
>
> * Tom Gundersen <teg at jklm.no> wrote:
>
>> Hi Ingo,
>>
>> On Thu, Oct 4, 2012 at 11:12 AM, Ingo Molnar <mingo at kernel.org> wrote:
>> > I'm wondering how to debug the following systemd problem:
>>
>> [...]
>>
>> > Here are the units that are showing some sort of error:
>> >
>> > lyra:~> systemctl --all | grep -i err
>> > exim.service              error  inactive dead          exim.service
>> > iscsi.service             error  inactive dead          iscsi.service
>> > iscsid.service            error  inactive dead          iscsid.service
>> > livesys-late.service      error  inactive dead          livesys-late.service
>> > livesys.service           error  inactive dead          livesys.service
>> > named.service             error  inactive dead          named.service
>> > postfix.service           error  inactive dead          postfix.service
>> > remount-rootfs.service    error  inactive dead          remount-rootfs.service
>> > ypserv.service            error  inactive dead          ypserv.service
>>
>> You might get useful information from:
>>
>> # systemctl status remount-rootfs.service
>>
>> (and similarly for the other ones).
>
> Querying those gives me the following uninformative output:

> Trying to start it again gives:
>
> [root at lyra ~]# systemctl start remount-rootfs.service
> Failed to issue method call: Unit remount-rootfs.service failed
> to load: No such file or directory. See system logs and
> 'systemctl status remount-rootfs.service' for details.

These are just units where other units try to order against, but which
are not available. It's nothing wrong here, besides the misguiding
output, which we should think about what to tell instead.


Could you add:
  systemd.log_level=debug systemd.log_target=kmsg log_buf_len=1M
to the kernel command line? It will print all userspace log to the
kernel buffer, which is the most reliable way to store the logs when
stuff goes wrong that early during bootup.

It should tell us more what's going on, and why you end up in the rescue shell.

This is the wiki page about debugging:
  http://www.freedesktop.org/wiki/Software/systemd/Debugging

Thanks,
Kay