To be clear, I'm not advocating for more systemd dependencies. It's just that as things stand today, someone installing docker.io for rootless containers will find that they simply fail with a cryptic error message.
Maybe Debian's dockerd-rootless-setuptool.sh script should use --exec-opt native.cgroupdriver=cgroupfs by default? Better still, maybe this situation should be detected by the software, and the cryptic error message replaced with an explanation of what is happening and that it can be fixed with either native.cgroupdriver=cgroupfs or dbus-user-session?
