[systemd-devel] Service output missing from journal?

[Michael Biebl]

Am Mo., 4. Juli 2022 um 19:36 Uhr schrieb Lennart Poettering
<lennart at poettering.net>:
>
> eOn So, 03.07.22 19:29, Uwe Geuder (systemd-devel-ugeuder at snkmail.com) wrote:
>
> > Hi!
> >
> > When I run the command given below on a current Fedora CoreOS system
> > (systemd 250 (v250.6-1.fc36)) I get a result I absolute cannot understand.
> > Can anybody help me with what is wrong there?
> >
> > $ systemd-run --user sh -c 'while true; do echo foo; df -h /var/log/journal/; echo $?; sleep 3; done'
> > Running as unit: run-r9a155474889b4d40a1ac119823bdc2bf.service
> > $ journalctl --user -f -u run-r9a155474889b4d40a1ac119823bdc2bf
> > [ ... similar lines redacted ... ]
> > Jul 03 15:25:08 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:11 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:11 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:14 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:14 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:17 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:17 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:20 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:20 ip-172-31-8-116 sh[366941]: Filesystem      Size  Used Avail Use% Mounted on
> > Jul 03 15:25:20 ip-172-31-8-116 sh[366941]: /dev/nvme0n1p4  9.5G  8.1G  1.5G  86% /var
> > Jul 03 15:25:20 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:23 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:23 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:26 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:26 ip-172-31-8-116 sh[366900]: 0
> > Jul 03 15:25:29 ip-172-31-8-116 sh[366900]: foo
> > Jul 03 15:25:29 ip-172-31-8-116 sh[366900]: 0
> > [...]
> >
> > So the output from the df command appears in the journal pretty rarely,
> > appearingly at random intervals. When I run the same loop on the
> > command line the output occurs every time.
> >
> > The problem was originally noted in a somewhat loaded system. However,
> > above reproducer (including the 2 echo commands and a shorter sleep)
> > shows the same problem even on an idling machine.
>
> https://github.com/systemd/systemd/issues/2913

I thought about this as well, but in this case the service is still
running. So I'm not sure if #2913 applies here.