Why do I see the stdout of the app from the container in /var/log/syslog of the host, even though I haven't configured anything?

Question

RSYSLOG

The scheme is like this.
The application writes logs to stdout. It is running in a docker container. That, in turn, is run through systemd.
As a result, I see the logs /var/log/syslog of the host.
But I didn't set anything. Everything is default. It is not clear which path works. Can you tell me what mechanism works? Is systemd sending logs or docker?
Well, how is it more correct to set up logging (what is the path and settings?), Taking into account multiline logs?

Answer 1

Systemd will redirect the container's stdout and stderr to the system log if run without the option-d/--detach