[systemd-devel] systemd-journald.service failed to start with systemd v189

[Kay Sievers]

On Mon, Sep 24, 2012 at 5:04 PM, Nicolas Aguirre
<aguirre.nicolas at gmail.com> wrote:
> 2012/9/24 Lennart Poettering <lennart at poettering.net>:
>> On Mon, 24.09.12 11:43, Nicolas Aguirre (aguirre.nicolas at gmail.com) wrote:
>>>
>>> Sometimes (around 1% of the time) my system doesn't start correctly.
>>> the init process takes 100% CPU. systemd-journal.service is not
>>> started correctly, and systemd tries to restart it in a loop.
>>> The log is here : http://pastebin.ca/2207127
>>>
>>> >From my understanding, the problem begins with
>>>
>>> [   12.169769] systemd[1]: Child 138 died (code=exited, status=1/FAILURE)
>>> [   12.169799] systemd[1]: Child 138 belongs to systemd-journald.service
>>> [   12.169830] systemd[1]: systemd-journald.service: main process
>>> exited, code=exited, status=1
>>>
>>> I would like to activate journald logs to see if there is debug output
>>> for this error. But i have no idea how to activate journal logs.
>>>
>>> I'm running angstrom and systemd v189 with a linux kernel v3.2.19 on
>>> arm cortex a8 CPU.
>>>
>>> Maybe somebody will have an idea ?
>>
>> Hmm, most likely there's something in server_init() in journald.c
>> failing. Normally, if something fails there it should print a message to
>> kmsg about that. But apparently we missued something there... :-(
>>
>> Could you try to add "log_notice()" messages at various spots in
>> server_init() and check if you can spot where the problem is generated?
>> you should see the messages in kmsg.
>>
>> Lennart
>>
>> --
>> Lennart Poettering - Red Hat, Inc.
>
> Ok,
>
> I did what you said, and it appears that the problem is located in
> journald.c, in system_journal_open function, when it tries to read the
> machine-id,
> it can't open /etc/machine-id.
>
> My RFS is readonly , I use Ubi/Ubifs root filesystem. To fix the
> problem of machine-id i added a symbolic link :
>
> ln -sf /var/volatile/machine-id /etc/machine-id
>
> IIRC systemd creates this machine-id file once, but in my case it's
> created every time i boot because /var/volatile is tmpfs. It seems
> that this symbolic link is broken when journald service starts,
> sometimes.
>
> To fix my problem, i will create a service which will mount the fs in
> rw, create the /etc/machine-id  and remount fs in ro if the machine-id
> is not found. It should work in my case because i'm using ubifs, but
> how to fix such problem in case of squashfs for example ?
>
> I don't have found the root cause, btw but it's a good start, thanks
> for your advises

We expect a writable /etc or machine-id file.

If you don't care about a persistent/stable one, you can make it an
empty file and systemd will take care to mount a randomly-created one
there.

So provide a machine-id in /etc or an empty file, but not a dangling
symlink please.

Thanks,
Kay