Re: [gentoo-user] syslog-ng: how to read the log files

[Marc Joliet]

Am Mon, 23 Feb 2015 12:10:18 -0600
schrieb Canek Peláez Valdés <caneko@×××××.com>:

> On Mon, Feb 23, 2015 at 11:49 AM, <covici@××××××××××.com> wrote:
> >
> > Canek Peláez Valdés <caneko@×××××.com> wrote:
> >
> > > On Mon, Feb 23, 2015 at 3:41 AM, <covici@××××××××××.com> wrote:
> > > >
> > > > Marc Joliet <marcec@×××.de> wrote:
> > > >
> > > > > Am Mon, 23 Feb 2015 00:41:50 +0100
> > > > > schrieb lee <lee@××××××××.de>:
> > > > >
> > > > > > Neil Bothwick <neil@××××××××××.uk> writes:
> > > > > >
> > > > > > > On Wed, 18 Feb 2015 21:49:54 +0100, lee wrote:
> > > > > > >
> > > > > > >> > I wonder if the OP is using systemd and trying to read the
> > > journal
> > > > > > >> > files?
> > > > > > >>
> > > > > > >> Nooo, I hate systemd ...
> > > > > > >>
> > > > > > >> What good are log files you can't read?
> > > > > > >
> > > > > > > You can't read syslog-ng log files without some reading
> software,
> > > usually
> > > > > > > a combination of cat, grep and less. systemd does it all with
> > > journalctl.
> > > > > > >
> > > > > > > There are good reasons to not use systemd, this isn't one of
> them.
> > > > > >
> > > > > > To me it is one of the good reasons, and an important one.  Plain
> text
> > > > > > can usually always be read without further ado, be it from rescue
> > > > > > systems you booted or with software available on different
> operating
> > > > > > systems.  It can be also be processed with scripts and sent as
> email.
> > > > > > You can probably even read it on your cell phone.  You can still
> read
> > > > > > log files that were created 20 years ago when they are plain text.
> > > > > >
> > > > > > Can you do all that with the binary files created by systemd?  I
> can't
> > > > > > even read them on a working system.
> > > > >
> > > > > What Canek and Rich already said is good, but I'll just add this:
> it's
> > > not like
> > > > > you can't run a classic syslog implementation alongside the systemd
> > > journal.
> > > > > On my systems, by *default*, syslog-ng kept working as usual,
> getting
> > > the logs
> > > > > from the systemd journal.  If you want to go further, you can even
> > > configure
> > > > > the journal to not store logs permanently, so that you *only* end up
> > > with
> > > > > plain-text logs on your system (Duncan on gentoo-amd64 went this
> way).
> > > > >
> > > > > So no, the format that the systemd journal uses is most decidedly
> *not*
> > > a reason
> > > > > against using systemd.
> > > > >
> > > > > Personally, I'm probably going to uninstall syslog-ng, because
> > > journalctl is
> > > > > *such* a nice way to read logs, so why run something whose output
> I'll
> > > never
> > > > > read again?  I recommend reading
> > > > > http://0pointer.net/blog/projects/journalctl.html for examples of
> the
> > > kind of
> > > > > stuff you can do that would be cumbersome, if not *impossible* with
> > > regular
> > > > > syslog.
> > > >
> > > > Except that I get lots of messages about the system journal missing
> > > > messages when forwarding to syslog, so how can I make sure this does
> not
> > > > happening?
> > >
> > > Could you please show those messages? systemd sends *everything* to the
> > > journal, and then the journal (optionally) can send it too to a regular
> > > syslog. In that sense, it's impossible for the journal to miss any
> message.
> > >
> > > The only way in which the journal could miss messages is at very early
> boot
> > > stages; but with a proper initramfs (like the ones generated with
> dracut),
> > > even those get caught. You get to put an instance of systemd and the
> > > journal inside the initramfs, and so it's available almost from the
> > > beginning.
> > >
> > > And if you use gummiboot, then you can even log from the moment the UEFI
> > > firmware comes to life.
> >
> > So, I get lots of messages in my regular syslog-ng /var/log/messages
> > like the following:
> > Feb 23 12:47:52 ccs.covici.com systemd-journal[715]: Forwarding to
> > syslog missed 15 messages.
> >
> > So, I saw a post on Google to up the queue length, and I uped it to 200,
> > but no joy, still get the messages like the one above.
>
> Are you using the unit file provided by syslog-ng (systemd-delta doesn't
> mention syslog)? Also, is /etc/systemd/system/syslog.service is a link
> to /usr/lib/systemd/system/syslog-ng.service?
>
> I do, and I don't get any of those messages. I use the default journal
> configuration. According to [1], this should be fixed.

I remember getting a small number of messages like that, too, on my laptop.
However, it's at the university, so I can't check now to see what types of
messages were missed (if any; if I understand [1] correctly, those messages are
most likely bogus?).

But yeah, that's any idea, Covici: see what's in /var/log/messages, compare that
to the journalctl output, and check if any messages were actually missed ("diff
-U" might be of help here).  And if/once you did that, what kinds of messages
were missed, if any?  If those messages really are bogus, you shouldn't see any
differences between the two.

> Regards.
>
> https://github.com/balabit/syslog-ng/issues/314

Note that that fix would only be in the ~arch version of syslog-ng, the current
stable version (3.4.8) is a few months too old.

-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup