replacing rsyslogd in minimal with journald [was Re: systemd requires HTTP server and serves QR codes]

Lennart Poettering mzerqung at
Wed Oct 10 23:48:07 UTC 2012

On Wed, 10.10.12 16:50, Kevin Fenzi (kevin at wrote:

> "My laptop started acting up last tuesday, I should see whats in the
> logs from then"
> "I'd like to run a daily report on my logs"

These two are much better implemented via explicit time seeks. The
journal APIs support that just fine, journalctl currently
doesn't. However it's trivial to add that based on the lower level APIs,
the only thing that stopped me from doing that so far is that for that
we'd have to come up with a nice way to parse calendar timestamps, and I
want to be careful about that. that said the idea is to have two command
line args to journalctl where you can pass things such as:

$ journalctl --start-time=2012-10-01
$ journalctl --start-time=-5d
$ journalctl --start-time=2012-01-01 --end-time=2012-05-02

And this would do the right things. Since the journal will coalesce the
current journal and the rotated ones into one this will simply show you
everything that matches.

Of course the time expressions for this need to be powerful enough so
that people can trivially express things like "everything from today",
or "everything since two weeks ago" and suchlike.

> "This thing might have messed up when I last booted... uptime shows 16
> days"

For this we already have "journalctl -b" which only shows messages from
the current boot. We'll probably extend that later so that you can pass
"journalctl -b4" or so which would show you the messages from 4 boots
earlier only.

The takeaway here is that rotation is not a feature for finding
things. There are much better ways to find things and we should make
them available, and we can, because the backend allows that.


Lennart Poettering - Red Hat, Inc.

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