Collect Elemental system logs and send to Rancher

I would like to collect Elemental OS syslogs and send them to Rancher because Elemental lose logs at each reboot and I need to debug unexpected reboots.
Reading the documentation seems Rancher collects only k8s and application logs but not syslogs of the underlying os.
Is it true?
Can you help me?

@mgiammarco Hi, if like openSUSE does this OS use systemd and journalctl? If so to make persistent, either edit the journalctl.conf file and change the storage option from auto to persistent, or create the directory /var/log/journal should keep previous logs.

Thank you it works.
But what about collecting them?
Can I use the integrated logging system in Rancher?
Or do I need to make a custom ISO enabling rsyslog or something similar?

@mgiammarco See

But if you want the current system log you can run journalctl --file /var/log/journal/$(cat /etc/machine-id)/system.journal > host_system_log.txt and tar that up, or can see them all in the directory via ls -lat /var/log/journal/$(cat /etc/machine-id)/ latest to oldest order. You could then use the above command replacing system.journal with system@lots_of-numbers.journal for a specific date. Then create a tarball as required…