[systemd-devel] Are logs at /run/log/journal automerged?

[Yuri Kanivetsky]

Hi,

I'm experiencing this on Digital Ocean. The machine id there changes
(which I think shouldn't happen) on the first boot (supposedly by
cloud-init). In Ubuntu 22.04 droplets, where logs are stored at
/var/log/journal, that leads to journalctl outputting no records
(because the log for the new machine-id has not been created), unless
I pass --file or --merge. Also, the records continue to be added to
the old log (for the old machine id).

In CentOS 9 droplets, where logs are stored at /run/log/journal,
journalctl outputs records from all 3 files:

cb754b7b85bb42d1af6b48e7ca843674/system.journal
61238251e3db916639eaa8cd54998712/system at 6600bdad291b419c8a0b1fea2564c472-0000000000000001-0005e6d123825866.journal
61238251e3db916639eaa8cd54998712/system.journal

In this case records also are being added to the old log. But the new
log somehow contains the beginning of the log (starting with boot).

Is my guess correct? Logs at /run/log/journal are automerged, logs at
/var/run/journal aren't.