Bug 81019

What precisely do you mean by "logging"? syslog()? or stdout/stderr logging?

My logging always works fine ehre, regardless if syslo() or stdout/stderr style logging, and regardless how many times i restart a service...

Can you tell me exactly what I need to do to reproduce the issue?

I did some more testing today, and my results are weird, but I suspect it's due to my peculiar setup.
I have /var/log as a tmpfs ('tmpfs /var/log tmpfs defaults,noatime,nodiratime,mode=0755,size=16M 0 0').

0. Testing software
Simple printf() loop, binary at /home/user/test-logging:

#include <stdio.h>
#include <unistd.h>

int main(int argc, char *argv[]) {
  int counter = 0;

  while (1) {
    printf("<5>Counter: %d\n", counter);
    fflush(stdout);
    sleep(3);
    counter++;
  }
}

Service file, saved at /etc/systemd/system/test-logging.service:

[Unit]
Description=Logging tester
After=network.target

[Service]
ExecStart=/home/user/test-logging
WorkingDirectory=/home/user
Restart=always

[Install]
WantedBy=multi-user.target

1. Test one
Systemd and journald have been running since boot, where journald.conf has:

[Journal]
Storage=persistent
SyncIntervalSec=30m
SystemMaxUse=8M

At shell:
systemctl start test-logging
systemctl status test-logging - did it a couple of times, no counter output logged whatsoever
systemctl stop test-logging

2. Test two
Modified journald.conf to have only:

[Journal]
SystemMaxUse=8M

At shell:
systemctl restart systemd-journald
systemctl start test-logging
systemctl status test-logging - did it a couple of times, counter output is being logged as intended
systemctl restart test-logging
systemctl status test-logging - still logging as it should
systemctl stop test-logging

3. Test three
So I added back my two custom options to journald.conf:

[Journal]
Storage=persistent
SyncIntervalSec=30m
SystemMaxUse=8M

At shell:
systemctl restart systemd-journald
systemctl start test-logging
systemctl status test-logging - did it a couple of times, logging well as in the previous test!
systemctl stop test-logging


In a way my problem seems to be solved, though I do not understand exactly why the logging works as the above tests show. My guess is that the tmpfs /var/log with Storage=persistent causes some trouble on boot and systemd is not logging; then restarting it without the Storage options invokes some setup code, so that from that point the logging works regardless of Storage or SyncIntervalSec values...

Please feel free to close this issue if the above behaviour is a known condition/intended feature etc.

Hmm, btw, we log to /run/log/journal (which is a tmpfs) if you leave Storage=volatile... It's weird, to make /var/log/ a tmpfs, if there's already /run/log for that...

Closing all stale bugs with NEEDINFO. Please open a new bug at https://github.com/systemd/issues if the problem still occurs.