Unexpected default LogDriver on rootless containers when PID listings are hidden (hidepid > 0) #2533
Description
This follows this discussion.
The default LogDriver election indirectly depends on func useSystemd() bool. It reads /proc/1/comm and expects its value to equal systemd.
Troubles arise when the host system is hardened to hide PID listings from non-root users. On such system, rootless containers end up with a different LogDriver, despite Systemd and Journald being fully supported.
podman-logs knows how to find its logs, so this may not cause immediate issue. However, with Quadlet containers, which are defacto managed by Systemd, units logs aren’t accessible through journalctl --user (messages’ _UID are set to containers namespaced user ids; not actual user id).
An easy workaround is to specify LogDriver=journald in the quadlet files.